Reconciling Just Causes for Armed Humanitarian Intervention


Michael Walzer argues that the just cause for humanitarian intervention is not met if there are only “ordinary” levels of human rights abuses within a state because he believes that respecting the right to collective self-determination is more morally important than protecting other individual rights. Several prominent critics of Walzer advocate for a more permissive account of a just cause. They argue that protecting individuals’ human rights is more morally important than respecting a right to collective self-determination. I argue that these two accounts are far more similar than either Walzer or his critics realize because collective self-determination requires the protection of some human rights in order to allow each person the opportunity to participate in collective choices. Consequently, the just cause for intervention is met whenever at least some important human rights of one person are violated and others are being credibly threatened. The counter intuitive conclusion of my argument is that justified interventions can actually promote rather than undermine collective self-determination because just interventions allow innocents, who otherwise would have excluded from this process, the opportunity to contribute to collective choices. Of course, a just cause is insufficient in itself for intervention to be permissible because other just war precepts must also be met.


Humanitarian intervention (intervention for short) is any military violation of state sovereignty without the consent of the target state’s government taken by one or more foreign actors who have as a central purpose the protection of innocents from severe human rights violations (McMahan 2010, p. 44; Pogge 2003, p. 93; Pattison 2010, pp. 24–30; Fabre 2012, p. 166). Humanitarian interventions can include the widespread use of force such as occurred in Kosovo in 1999 or Libya in 2011 or it can include more limited military actions such as a no fly zone or a targeted drone strike. The central question I address in this paper is when is the just cause for humanitarian intervention met.

Some scholars argue the importance of collective self-determination weighs against the just cause of intervention except in extreme cases of human rights abuses such as genocide or crimes against humanity, while others argue that the just cause is met to only protect one or a few from serious human rights abuses. My thesis is that even those who weigh heavily collective self-determination as a reason against intervention must accept that grave human rights abuses that impede the ability of just one innocent person to participate in making such collective decisions with similarly grave, credible threats against others can meet the just cause criterion for intervention. This is because collective self-determination requires all adults to not have their rights to contribute to collective choices violated. One or more unjust killings or other severe human rights abuses that prevent participation in collective choices consequently undermine collective self-determination. Relevant human rights abuses can include beatings and torture that themselves prevent those targeted from participating in collective choices and indirectly cow others into refraining from participating. According to this account of collective self-determination, if humanitarian intervention can prevent just one unjust killing or other relevant severe abuse of human rights, then the just cause criterion is met insofar as collective self-determination is the justification for nonintervention. I want to emphasize that past human rights violations do not necessarily meet this criterion. Only if one or more severe human rights violation of the relevant type will likely happen in the future and could be prevented by foreign actors is the criterion met. My argument is conditional: if one believes collective self-determination is very important, then one must accept that the protection of certain human rights is necessary in order to realize collective self-determination. I neither claim nor do I believe that protecting human rights is primarily instrumentally important. Rather, I believe that protecting human rights is intrinsically important.

There are several benefits of my account. First, while emphasizing that collective self-determination is a matter of degree, it can explain why certain human rights abuses undermine collective self-determination even when they do not rise to the level of mass atrocities. A state can be generally collectively self-determining while imperfectly protecting relevant human rights and yet not have a valid claim against humanitarian intervention because it could be better protecting relevant human rights – and more collectively self-determining (Wellman 2012). Second, it sets limits on the legitimate aims of intervention because the intervention must be aimed at guaranteeing human rights while not permitting interventions aimed at imposing foreigners’ will in areas other than protecting those rights that are necessary to exercise collective self-determination.

This may appear to permit too many armed interventions, but it does not because for intervention to be permissible other just war precepts, such as proportionality, must be met. As I discuss further below, these other criteria would generally prohibit most types of military interventions even if the just cause criterion were met.

My argument largely reconciles when the just cause criterion of just war theory is met according to Michael Walzer, who weighs heavily collective self-determination as a reason against humanitarian intervention (Walzer 1977, 1980, 2007), and several of his most prominent critics such as Charles Beitz, David Luban, and Christopher Wellman, who value protecting individual human rights more than Walzer (Luban 1980a, b; Beitz 19802009; Doyle 2009; Wellman 2012). My argument reconciles these scholars’ divergent views because the just cause principle is met for humanitarian intervention if individuals are having their human rights severely violated either if one believes that collective self-determination or protecting human right matters morally more. Although I show that Walzer and his critics have nearly identical just cause criterion, the reasons why they permit intervention continue to differ. Some of Walzer’s critics think there is a just cause to prevent important human rights violations of one or more people, whereas for Walzer there is a just cause for intervention just in case a people are not collectively self-determining. If a collective is self-determining, on Walzer’s view no outside actor has a permission to intervene militarily. One can agree with Walzer on this point, but disagree with him under what conditions a state is not collectively self-determining. Specifically, in my view, foreign actors would have a just cause to intervene where there is at least one severe human rights violation with credible threats of additional, prospective ones even if they are not widespread of systematic. Thus the main target of my argument is Walzer and others who share the belief that collective self-determination is possible even when some people who are members of the society in question are being unjustly killed or having other human rights violated that are necessary to contribute to collective choices such as being tortured, unjust imprisonment, or being physically attacked.

David Rodin has made an argument similar to mine, but my thesis differs in important ways from his (Rodin 2014). Rodin “affirms the right of people to determine their own political settlements without violent coercive interference from either foreigners or compatriots” (Rodin 2014, p. 243). He goes on to write that “Mill and Walzer think that intervention should protect a space for indigenous violent politics. I believe that intervention should protect a space from violent politics” (Rodin 2014, p. 257). The main difference of my argument from Rodin’s is that rather than proposing a new view on the just cause for intervention from outside of existing accounts, I show that even from within Walzer’s own position regarding when the just cause for intervention is met, preventing severe human rights violations of certain types qualify as a just cause.

I advance these arguments in the following order. First, I discuss the two leading positions on when and why the just cause for intervention is met. Second, I present my account of collective self-determination and show why it largely reconciles the two leading accounts of just cause for intervention. Third, I show that just war theory already has a number of constraints that would not make a permissible just cause result in many unjust wars. Fourth, I consider a number of objections and then conclude.

The Morality of State Sovereignty and Just Causes for Humanitarian Intervention

Accounts for what qualifies as a just cause for intervention focus on the relative importance of two principles, state sovereignty and human rights. Human rights are mostly individual rights, whereas state sovereignty is widely equated with a form of collective determination. Often the two are taken to be in tension because when a state violates human rights one can either respect state sovereignty or protect human rights. Building on an argument Kofi Annan advanced in 1999, David Rodin calls this the “dilemma view” (Annan 1999; Rodin 2014, p. 244). The alternative view Rodin calls the “conditionality argument” (Rodin 2014, pp. 244–245). Proponents of this view hold that state sovereignty is conditioned on the protection of certain human rights, so there need not be any tension between protecting human rights and respecting state sovereignty. This is a basis for the idea of the responsibility to protect (R2P), although the 2005 World Summit Outcome Document limits just causes to genocide, crimes against humanity, war crimes, or ethnic cleansing.

State sovereignty is supreme authority within a given territory over a certain people (Philpott 2001, pp. 16–17). Sovereignty entails a bundle of rights, such as the right to non-interference from external groups and the right of the group to internally order their affairs as they see fit (Wellman 2012: 126). I argue below that a state’s actions can forfeit certain of these rights, but need not entail forfeiting all of them. As Jeff McMahan puts it, “the principal reason that humanitarian intervention is contentious is that it seems to violate the target state’s sovereign right to control its own domestic affairs” (McMahan 2010, p. 44). This reason, however, just pushes the question back one step. Why should a state’s sovereign control of its own domestic affairs matter morally, and matter so much?

State sovereignty is morally important for three main reasons. One reason is to limit international aggression of powerful states against weak states. Undermining state sovereignty by permitting humanitarian intervention may allow powerful actors to further their own interests by abusing the justifications for when intervention is permissible. For instance, Russian leaders claimed that their invasion of Georgia in 2008 was based on the R2P and humanitarian motives (Bellamy 2011, p. 55–56). A second, related reason humanitarian intervention is contentious is that sovereignty permits collective self-determination. This is morally important because it allows groups to make domestic laws reflect cultural, religious, traditional, ethical, and other differences among peoples. Although some such as Robert Goodin call for radically altering if not altogether abolishing state sovereignty on democratic grounds (Goodin 2007), many accept that states can be legitimate to some degree in part because states allow some degree of collective self-determination. A third reason why sovereignty and nonintervention is important is because interveners almost always unintentionally although foreseeably kill and maim innocents. All are potent objections and must be addressed by any theory of the just cause of humanitarian intervention.

Both Walzer and his critics address these concerns in their competing theoretical positions regarding when the just cause for humanitarian intervention is met.Footnote 1 They agree that the violation of human rights is a trigger for when the just cause for intervention is met, although Walzer and his critics differ on the relative moral importance of human rights and collective self-determination, and how severe and how widespread human rights violations must be in order qualify as a just cause. Whereas Walzer holds that collective self-determination is possible unless there are widespread or systematic severe human rights violations and that collective self-determination is generally more important than ordinary levels of human rights violations, his critics defend the view that protecting individuals’ human rights is morally important enough to override, or make the state forfeit, the right to collective self-determination because it is inadequately protecting human rights. Below I will show that these two justifications for the just cause of intervention in fact result in nearly identical just cause criteria. I first briefly summarize the two accounts.

Walzer is the most prominent proponent of the first position, which holds that collective self-determination is so morally important that groups embodied in states should have sovereign rights even if state or non-state actors violate citizens’ human rights at ordinary levels. States should have strong but not absolute rights, Walzer argues. A state ought to enjoy its sovereignty if there is a “fit” between the people and its government (Walzer 1980, p. 212, p. 214, pp. 216–217). Walzer means by this that a state retains its right against intervention if its “people governed in accordance with its own traditions. This presumption is simply the respect that foreigners owe to a historic community” (Walzer 1980, p. 212). This would “rule out intervention in cases of ‘ordinary’ oppression” because we cannot assume that there is a misfit except when there are massive and severe human rights violations (Walzer 1980, p. 218). The just cause for humanitarian intervention is met if a state commits genocide, mass killings, slavery, or ethnic cleansing (Walzer 1977, 1980, p. 217–218).

In additional to the fit argument, Walzer suggests that there are epistemic reasons to limit when the just cause for intervention is met to cases of extreme human rights violations. According to Walzer, foreigners are not in a position to know whether there is a fit between a people and its government because foreigners are unable to collect enough information to make such judgments – except in rare and extreme cases (Walzer 1980, p. 212). Notice that Walzer’s argument is that even if intervention could be proportionate, potential interveners must still refrain on moral grounds if there is sufficient fit between a government and its people because collective self-determination is more important than ordinary oppression and human rights violations. One might surmise that this is because Walzer does not value human rights, but this is wrong. He writes, “[i]ndividual rights (to life and liberty) underlie the most important judgments that we make about war” (Walzer 1977, p. 54). He goes on to write that “[s]tates' rights are simply their [individual rights’] collective form” (Walzer 1977, p. 54). What is at issue is the relative importance of various rights. For Walzer, protecting individuals’ rights to live in a collectively self-determining society is more important than protecting some people’s rights against unjust attack, even if such attacks are lethal as long as they do not rise above a certain level.

Many have raised a number of criticisms against Walzer’s epistemic arguments and his views on the relative weight of individuals’ rights to collective self-determination and other individual rights. Consider first his epistemic arguments. Why foreigners can have enough information in some but not all cases, and only in the cases Walzer suggests, remains unclear given Walzer’s analysis (Luban 1980b, p. 395). For instance, why should foreigners be able to know that slavery, but not routine torture, creates a misfit between a people and their government? Furthermore, knowing that there is routine torture or slavery depends upon foreigners having good information, exactly what Walzer says foreigners cannot have.

There are problems too with his arguments for the importance of state sovereignty. Many “historic communities” are in fact states created by foreign, colonial powers or taken by the unjust use of force. And many states are composed of more than one historic community whose members feel distinct from other groups within the same state. One of the most problematic features of Walzer’s account is that it is unclear why massacres show a misfit between a people and its government, or why such massacres shows a society is not governing itself consistent with its traditions. If a tradition is the passing on of ideas and practices from generation to generation, many societies throughout the world have traditions of massacres (Beitz 2009, p. 334). Thus, if respect for collective traditions is the reason foreigners should not intervene, it is unclear why mass human rights violations should qualify as a just cause for intervention. Finally, even if there is a “fit” between a government and its people whom are ordinarily tortured or often have their human rights violated in other ways, why does this justify nonintervention? Walzer’s critics make such points and endorse a more permissive account than Walzer’s.

Proponents of the second account of the just cause for intervention place more value and emphasis on individual human rights other than the individual right to collective self-determination than Walzer. Apologists of this account hold that state sovereignty should be respected only in so far as it protects individual human rights. Wellman offers a paradigmatic view of these critics when he writes “if we take human rights as seriously as we should, then even a legitimate state has no principled objection to outsiders’ intervening in its internal affairs if this interference will prevent just a single human rights violation” (Wellman 2012, p. 119). On this view, states are primarily instrumentally useful. States are legitimate only in so far as they allow the protection of human rights. If, as Dworkin claims, individual rights generally “trump” most other considerations (Dworkin 1984), the just cause for intervention is more easily met than if one places emphasis on collective self-determination. These critics agree with Walzer that collective self-determination is important, but they give it less weight than him. Walzer’s critics’ basic argument is that if governmental or nongovernmental agents are violating individual rights, and intervention would prevent a greater number of human rights violations than nonintervention or any other policy, then intervention could be justified if all other just war conditions were met (Luban 1980a, p. 175; Wellman 2012).

Human Rights Necessary for Collective Self-Determination

In this section, I defend the view that collective self-determination requires the individual members of the collective the opportunity to participate in some way in collective decision-making and therefore collective self-determination is only possible when a number of human rights are guaranteed, including the right to not be killed unjustly. Footnote 2 A state where human rights violations justify humanitarian intervention need not forfeit all of its sovereign rights (Wellman 2012, p. 126). For instance, it can maintain the right to order its affairs internally, within limits. For instance, my argument suggests that foreigners cannot impose a presidential or parliamentary system of government on a state, but they can intervene to protect human rights. A number of rights violations could impede unjustly someone from participating in collective choices. These include beatings and torture that prevent certain people from participating in collective choices and have the unjust deterrent effect by intimidating others in refraining from participating political processes. Summary disappearances and arbitrary arrests can have the same impact.

By human rights violation I mean when one acts impermissibly against a human right held by another person (McMahan 2009, p. 10). By unjust killing I mean one in which an individual is killed who is not liable to defensive harm (liable for short). One is liable if one has forfeited his right against being attacked (McMahan 2009, p. 8). Innocents are those who retain their rights, specifically their right not to be attacked unjustly, and are therefore not liable (McMahan 2009, p. 8). It would not be wrong to attack a person who is liable if necessary and proportionate, whereas it is generally wrong to intentionally attack an innocent person. For example, a hostage taker who is responsible for his actions who lethally threatens an innocent person has forfeited temporarily his right not be killed for as long as he continues to pose a threat to at least one innocent person. The hostage taker is liable, but the hostage is innocent. My view is compatible with many prominent accounts of how and why individuals can become liable (Frowe 2010; Mapel 2010; McMahan 1994, 2005, 2009; Rodin 2002; Quong 2012; Walzer 1977). For instance, my argument is compatible with the view that one becomes liable just by posing a lethal threat, or if one believes that one must also be morally responsible or culpable for such a threat.

There is nothing in my account that precludes justified killings or other legitimate ways of excluding individuals from the opportunity to contribute to collective self-determination even though this too would undermine collective self-determination. There are at least two types of permissible killing. One is if someone has made himself liable to defensive harm and thereby forfeited certain rights including the right against being attacked, if necessary and proportionate to the threat. The second way is through what Jeff McMahan calls “infringing” rights of innocents (McMahan 2009, p. 10). By this, McMahan means that a necessary and proportionate number of innocents can be permissibly killed or otherwise harmed unintentionally as a side effect of a legitimate attack in war. This is widely accepted through the doctrine of double effect. It is important because interveners will generally kill and harm liable and innocent people.

My view is compatible with aspects of a diversity of leading accounts of collective self-determination. It can accommodate an unequal domestic distribution of political rights, such as John Rawls argues should be tolerated if some conditions are met (Rawls 1999), and it is compatible with representative democrats’ requirement of granting elected representatives more political power and political rights than average citizens. It is useful to consider briefly some of these positions of collective self-determination in order to show how my argument complements some accounts, and some aspects of these, while undermining others. Following Beitz, I classify the three positions on what is required for collective self-determination as maximalist, intermediate, and minimalist (Beitz 2009, pp. 336–338).

Maximalist accounts of collective self-determination require liberal democracy. Not only should people be able to voice their opinion about how collective choices should be made, but also they should be popularly sovereign. The people should “exercise control over outcomes” (Beitz 2009, p. 337). Representative liberal democracy requires an opportunity for individuals to collectively control political processes indirectly by granting adult citizens of a polity who have committed no crime the right to vote for politicians. Beitz calls this account maximalist because it has the most stringent requirements for collective self-determination of the three positions.

There are several problems with this view. First, there are problems in assuming even democratically elected leaders embody the will of the people. Political leaders often do not keep campaign promises, and so even if they win more than 50 % of the vote, their policies may represent merely a minority of those who voted (to put aside for the moment all of those who do not vote). Furthermore, majoritarian and to a lesser extent proportional representation electoral decision rules often result in a sizable dissenting minority even if politicians do keep their promises. Politicians have to make choices about unforeseen events that few anticipate and about which none can vote until after major decisions have already been made.

The following is an even more decisive rebuttal to the view that democratic states are sufficiently legitimate that intervention is impermissible. Even if we assume that leaders are always representative of a majority or supermajority, it is not clear how this is supposed to justify nonintervention when leaders commit or allow severe human rights violations of the relevant types. If a police force of a representative (or dictatorial) government unjustly violates the human rights of some, the harms remain morally objectionable.

Beitz’s second “intermediate” account requires that “outcomes reliably track a widely shared conception of the common good” such as by articulating a people’s interests, expressing dissent, publically associating, and so forth (Beitz 2009, p. 337). Proponents of the intermediate position resist the view that representative democracy is the only way collective self-determination is possible (Cohen 2006; Rawls 1999; Altman and Wellman 2009, chap. 2.). Rawls, for instance, argues that collective self-determination can occur without liberal, representative, democracy (Rawls 1999). According to Rawls, some peoples who organize themselves non-democratically deserve the same sovereign rights as those granted to democracies to collectively self-determine. These “decent hierarchical societies” are those that protect adequately a short list of human rights and meet other standards (Rawls 1999, pp. 64–67). In a jointly authored book, Altman and Wellman also reject that collective self-determination requires adults be granted the right to vote (Altman and Wellman 2009, chap. 2). Their sole criterion for when and why a group should be granted sovereign rights is that it can “adequately” protect individuals’ human rights domestically, excluding the individual right to democracy, and externally respect foreigners’ human rights (Altman and Wellman 2009, p. 3, p. 13). Although they use one of the same criteria as Rawls, their list of human rights that must be guaranteed in order to gain sovereign rights is longer than Rawls’s. Like Walzer, Altman and Wellman argue that collective self-determination is sufficiently important to preclude outside actors from intervening in a state’s affairs even if the intervention can better protect human rights of the target state’s citizens than the home country’s government so long as human rights are adequately protected.Footnote 3

The third, minimalist account, requires only that people be governed in accordance with their own traditions, whatever these traditions entail. If the traditions include torture or some unjustified killing, that is acceptable according to this notion of collective self-determination. The people need not be able to control political processes or even voice their opinions regarding how they think they should be governed. Beitz classifies Walzer as a minimalist because Walzer provides “no independent requirement that institutions offer the individual members of the group opportunities to control or influence political outcomes” (Beitz 2009, p. 337). Yet it is difficult to call this account of governance collective self-determination for the following reason.

My fundamental point of disagreement with the third view and potentially the other two is that collective self-determination is incompatible with some people having some important human rights violated. Specifically, collective self-determination is undermined whenever an individual has any right necessary to exercise collective self-determination violated. For instance, if one is unjustly killed or beaten because of one’s political views, one can reasonably claim that one’s right to participate in collective self-determination is not respected. But if one is not given holidays with pay (violating UDHR 24), this would not likely prohibit one from participating in collective self-determination. Self-determination is no longer truly collective when individuals are prohibited from contributing to collective decisions by being killed unjustly or having their human rights violated in other ways such as being beaten, tortured, arbitrarily imprisoned, and so forth. A floor rather than a ceiling, my account undermines those aspects of the three accounts of collective self-determination that permit severe human rights violations. Whether one believes that collective self-determination requires granting adults the right to vote or there are other ways to contribute to making choices collectively, all require the protection of some fundamental human rights.

I agree that a collective preference satisfaction is important for collective self-determination, but I disagree that it is sufficient for it. There are limits to what the collective can decide in order for a group to exercise collective self-determination.

Another reason such unjust killing is problematic for collective self-determination is that self-determination is an ongoing, iterative process. It requires the group make decisions over a period of time, and requires group members to have an opportunity to contribute over time. Of course, unjust killing prohibits members from making contributions after their deaths.

A different reason why such unjust killing undermines collective self-determination is because a collective consists of every group member. Of course group size can change by justifiable means such as births, natural deaths, permissible killings, and so forth. There can be a tension between collective preferences and preserving the collective. Of course many unjust acts do not impinge on a collective’s right to self-determination. For instance, a restaurant may unjustly refuse to serve a potential customer because of her skin color, but this would not directly undermine the patient’s ability to exercise contribute to collective self-determination. Not all injustices would qualify as a just cause for intervention.

One might object to this view of collective self-determination by arguing the following. Democratic states are above a threshold of self-determination whereas autocratic ones are not. Another way to put this objection is that collective self-determination is a binary category, and that just one or a few severe human rights violations of the relevant types do not sufficiently undermine a polity’s collective self-determination to claim that it is not self-determining. France, Norway, and Canada have severe human rights violations that might be preventable, but few would suggest that they are not collectively self-determining. The problem with this objector’s argument is that collective self-determination is not binary. Just as a country can be more or less democratic, a country can be more or less collectively self-determining. For instance, the founders of the Polity IV dataset categorize as democracies those countries that score 6 to 10 even though there is variation with this group.Footnote 4 But if one were persuaded of some form of threshold account of collective self-determination, my argument could still generally hold. Thus my argument that just one unjust killing undermines collective self-determination does not imply that a country is not mostly collectively self-determining. Foreigners could only protect human rights that are necessary to exercise collective self-determination.

The result of my argument is that any state that fails to minimize relevant human rights abuses meets the just cause for humanitarian intervention. The extent and type of permissible intervention is directly related to the number of severe human rights violations an intervener could prevent. This raises the question of who should be counted in proportionality calculations, and other checks that would be necessary in order to avoid such a permissive just cause being abused.

Constraints on Intervention

A serious objection to my argument is that many states would meet the just cause criterion because one can predict with a high degree of certainty that many states will continue to violate or allow violations of important, relevant human rights, and it would therefore permit too many interventions in practice. One might argue that well-intentioned leaders who are overconfident in their assessments of their likelihood of success could unintentionally misuse the just cause criterion proposed here, and malevolent leaders could abuse it in order to “dignify the sordid process of international politics” (Orwell 1945, p. 958).

My argument obviously lowers the bar for the just cause compared with Walzer’s view, but this does not undermine the validity and practical implications of my argument for several reasons. First, this objection concerns the conclusion of my argument, not its logical soundness or account of collective self-determination. Second, my argument does not reduce the just cause bar below where Walzer’s critics set it. Third, this account permits violating state sovereignty only to the degree necessary to protect individuals’ relevant human rights while leaving in place other components of collective self-determination. Thus even when the just cause condition is met, it places restrictions on to what degree the intervening authority can violate state sovereignty. Fourth, and most importantly, for any intervention to be permissible, all just war theory precepts must be met. With such a low bar for the just cause for intervention, proportionality, right authority, right intention, and likelihood of success requirements from just war theory would be especially important in curtailing when interventions would be permissible.

Consider the proportionality precept in more detail to see why such a low bar for the just cause for intervention would not have unintended consequences of morally permitting a great number of unjust wars. Thomas Hurka argues that jus ad bellum proportionality requires that “the destructiveness of war must not be out of proportion to the relevant good the war will do” and relevant goods are only those associated with a war’s just cause whereas all negative effects count (Hurka 2005, p. 35). Especially important in proportionality considerations are liability conditions of individuals. Many just war theorists argue all fully liable individuals should not be counted in proportionality assessments (McMahan 2009, p. 19; Rodin 2002, p. 78). Whether all combatants who are members of states that are at war are liable is a central debate within just war theory. Walzer believes in the moral equality of combatants (Walzer 1977, pp. 34–37, p. 136, p. 145). This view holds that all soldiers who are members of countries that are at war are fully liable. McMahan has resisted this view by arguing that soldiers who fight on the just side have done nothing to make themselves liable – they have not forfeited any of their rights – so it is generally (but not always)Footnote 5 impermissible for anyone to attack them intentionally (McMahan 2009). Whatever views one has on who is liable and why can apply to proportionality. If one agrees with Walzer, only the vast majority of civilians count in liability calculations.Footnote 6 If McMahan persuades one, just combatants’ lives must be weighed equally to all innocent civilians in proportionality calculations. Whether one includes only innocent civilians, or whether one includes just combatants with innocent civilians in proportionality calculations, one reason killing innocent individuals is problematic is because their deaths undermine the collective self-determination of their respective communities.

Proportionality is doubly relevant on my account. One widely accepted reason proportionality is important is because it attempts to guard against war making things worse than they otherwise would have likely been. But on my account it is additionally important because it sets limits on intervention because disproportionate acts would also undermine collective self-determination.

My argument provides another action-guiding principle for what types and aims of intervention are permissible and impermissible. If intervention aimed at ends other than preventing the relevant types of human rights abuses (say, imposing a certain policy unrelated to relevant human rights abuses on the target country), it could undermine collective self-determination and therefore would be impermissible according to justifications weighing heavily collective self-determination. An intervention is permissible on my account if it would save more innocents’ lives than not intervening, so long as those intentionally targeted individuals have made themselves liable to defensive harm and the other just war theory criteria are met, because saving these lives maximizes collective self-determination.

Another reason why a low bar for the just cause of intervention would not make many interventions permissible all things considered is because many interventions would not likely meet another widely accepted necessary just cause for war, namely a reasonable chance of success. In countries with well-developed government capacities, it is generally unlikely that against standard non-state threats, intervention would not increase the chances of protecting relevant human rights beyond what the chances are of letting the domestic government take action because the domestic government has the relevant capacity, knowledge, and resources.

Thus interventions in states that generally respect human rights such as Norway, Denmark, France, and so forth would almost certainly be impermissible on my view for a variety of reasons including a low likelihood that intervention would be successful and proportionate. Even with a permissive just cause, foreign actors are unlikely to be able to meet the just war theory criteria other than just cause except in rare circumstances.


Another objection is that because leaders are institutionally constrained and forced to choose among options all of which will harm some people, many of their actions that would be wrong were they not in such a constrained position should be excused to some degree. Walzer calls the “problem of dirty hands” any situation where an individual must choose between options any of which would result in unjust harms to innocents (Walzer 1973). Rulers and their apologists may argue that states should not be liable to intervention so long as their leaders minimize harms given the choices available to them. Or some might argue that intervention should be prohibited so long as rulers make the better choice for their citizens, even if some people have their human rights violated. But even if leaders minimize harms to innocents given their capacity to do so, that does not explain why a society should be exempt from intervention if it could prevent additional severe human rights violations. Even if a government were only allowing severe human rights violations because it is too weak to prevent them, on my account humanitarian intervention would be permissible if it could prevent one or more of these (assuming the targets are liable and all other just war precepts are met). Take Somalia. The official government is extremely weak. But if intervention could prohibit the slaughter of innocents in a part of the country where the government does not control, on my account the just cause could still be met.

Another view is that individual liability to defensive harm is independent from a state or a group forfeiting their right against nonintervention. An individual can remain innocent because she has done nothing to make herself liable, while a state can forfeit its right to nonintervention if it is unable to protect innocents or if it is unwilling to do so. Violations of state sovereignty are permissible in some circumstances even in some cases when leaders retain their individual rights, and even when states do not forfeit other aspects of their sovereignty. As the authors of the foundational document of the responsibility to protect put it, even if states are unable (and not just unwilling) to protect innocents from mass atrocities, the just cause for intervention can be met (although they set a higher bar for just cause than I argue for here) (Evans et al. 2001, pp. VIII, XI, 16–17, 29, 33, 69, 74–75). I do not assume that state leaders are liable to harm whenever there is a just cause, because leaders could be doing everything in their power to minimize violations of the right to not be unjustly killed, but still not minimize severe human rights violations because of a lack of capacity. Imagine that a rebel group forcibly took and held territory in which it is systematically unjustly killing individuals, while a government is not committing any unjust killing and doing all it can to prevent the rebels from carrying out unjust killings. The just cause for intervention is met in this case on my account, although only the rebels committing the unjust killings and not the just government may be targeted intentionally.

Walzer is thus close to some of his critics in another way as well. As Wellman writes, “legitimate states will retain sovereignty over all matters unrelated to the protection of human rights” (Wellman 2012, p. 127). The same is true for Walzer, but again for a different reason. States can be legitimate in the sense that they retain the right to govern their affairs as they see fit with the constraint being that if they are unable to protect the human rights of innocents that they forfeit that and only that aspect of their sovereignty because the protection of certain human rights is necessary to exercise the right to collective self-determination.

A second objection is that the just cause for intervention can only be met when mass atrocities occur or are imminent because proportionality can only be met if there are widespread abuses since intervention inevitably kills many innocents. There are reasons to think that proportionality can be met in situations where there are not large numbers of innocents being killed, even if such situations are rare. Targeted bombing campaigns, no fly zones, and drone strikes for instance can kill far fewer innocents than large ground invasions. The US uses drone strikes regularly against alleged terrorists in Pakistan, Yemen, Somalia, and potentially elsewhere.Footnote 7 Despite the controversies surrounding drone strikes, they can result in far fewer harms to innocents than a war on the scale of the US led interventions of Kosovo or Libya. Intervention does not always require large numbers of ground troops. Imagine there is very good intelligence that a suicide bomber is making his way on an open road to a city where he will attack and kill scores of civilians in a market. The scale of the killing of the bombing would be far below say the more than 190,000 people that have been killed so far in the Syrian civil war. But if an attack on this man on an open road where there would not be civilian casualties, such an attack could be permissible all things considered. This fact undermines the objection that humanitarian interventions can only be proportionate when there are widespread or systematic human rights violations.

A third potential objection is that my argument would prohibit humanitarian intervention altogether because any armed intervention almost inevitably kills innocent as well as liable individuals, and therefore would undermine collective self-determination by unjustly taking the lives of innocents. Although it is correct that unjustified killing of innocents would undermine collective self-determination and hence the just cause on my account, it is incorrect to conclude from this that intervention would be impermissible because my view allows killing a proportionate number of individuals when the just cause is met. Foreseeably but unintentionally killing a necessary and proportionate numbers of innocents may be permissible in some circumstances in order to achieve a just aim.

Fourth, another, related, potential objection to my argument is that it unfairly prohibits some types of justifiable punishment such as the state temporarily or permanently disenfranchising criminals from participating in collective decision-making. For instance, some US states prohibit convicted felons from voting while incarcerated or even after they serve their time (Manza and Uggen 2006). Such punishment is possible given my thesis (although I disagree with such practices on other grounds) because the right to participate in collective self-determination is not absolute. It is consistent with my thesis because I never claim that all adults must always be able to contribute to collective self-determination no matter what wrongs they commit. Rather, my claim is negative: violating relevant human rights unjustly prohibits those individuals from participating in (or waiving their right to participate in) collective self-determination.

Fifth, one might object that because not all military interventions are the same, there should be a different theory for when each type is permissible. One might think that different sorts of humanitarian interventions should be distinguished because some affect only a few people whereas others can destroy a whole country’s economy and kill large numbers of people. While it is true that these are different types of interventions, I have found no one who makes a convincing argument for why different moral criteria should apply to different types of interventions. The morally relevant features are identical for each type of military intervention and hence the same criteria should apply to all.

An anti-paternalist could make a sixth objection (Beitz 2001, pp. 273–274). Liberals defend the view that even if C could be made better off if D directed parts or all of the C’s life, so long as C is not violating directly or indirectly anyone’s rights, D should not be permitted to coercively interfere in C’s life without her consent. Those defending parents’ rights regarding making choices for their children defend a similar point (Altman and Wellman 2009, pp. 14–15). Imagine that some individuals could nurture and raise children better than some parents. So long as the parents do not violate the children’s rights, the anti-paternalist holds, other people should have no right to coercively interfere in how the child is reared. The same anti-paternalist principle should apply to states, this objector to intervention argues. Intervention is impermissible because states have rights over their citizens, just as parents do over their children. As Wellman notes, this critic cannot explain the relevant dissimilarity about why a parent violating the right of her child in the case of a family, which would permit and indeed require coercive action to protect the child, fails to apply to states (Wellman 2012, p. 127). On my account, states, like parents, are allowed to govern just poorly enough so that no foreign intervention could improve the marginal protection of individuals’ human rights (because protection of that right is required for collective self-determination).

The final objection is that some might think that my argument requires minimizing severe human rights abuses. This is incorrect. There are many morally important goods and nothing in my argument suggests that preserving the conditions necessary for nonintervention must trump all other considerations. Although protecting people’s right to not be unjustly killed is extremely morally important, there are a plurality of goods that deserve resources, only one of which is the condition necessary for collective self-determination. In this way, my argument is compatible with a diversity of accounts of collective self-determination, even though some groups might choose to not minimize severe human rights abuses and thereby meet the just cause for intervention. My account allows communities to decide how to allocate resources to a large degree.


I have argued that ostensibly competing accounts of the just cause criterion for humanitarian intervention are more similar than is widely accepted, because collective self-determination requires individuals to have the opportunity to contribute to collective decision-making, and many types of severe human rights violations undercut this. There is a just cause for humanitarian intervention whenever leaders are unable or unwilling to minimize prospective violations individuals’ human rights. This holds whether one views human rights or collective self-determination as more important, because certain individual rights are necessary to exercise collective self-determination. My argument does not suggest that human rights or collective self-determination are more morally important. Such a low bar for the just cause of humanitarian intervention will not problematically authorize many more military humanitarian interventions, because other just war precepts such as proportionality and reasonable chance of success must also be satisfied for an intervention to be just. My argument does nothing to weaken other just war precepts.

The counterintuitive conclusion of my argument is that when there is a just cause and the other just war precepts are met, not only does proportionate humanitarian intervention not violate collective self-determination, but in fact it actually guarantees collective self-determination because it protects innocents so that they can participate in the collective decision-making. Reformulating the debate about when and why it is considered permissible to intervene in this way neither sides with Walzer nor his critics. It does not favor Walzer because there need not be widespread or systematic violations of human rights for the just cause criterion of humanitarian intervention to be met. But it does not side with his critics because the justification I use to determine when intervention is permissible is grounded in collective self-determination. The just cause for intervention is met whenever there is likely going to be a violation of an individual’s rights severe enough to undermine one’s ability to participate in collective self-determination, which will likely vary on the standard of what constitutes collective self-determination; what is common to all coherent accounts of collective self-determination is that they are undermined if someone is unjustly killed. My account of to what degree states should be sovereign is an instrumental justification for why one human right is important. Footnote 8 Yet I do not deny that human rights are intrinsically valuable. That human rights are intrinsically important and instrumentally required to exercise one’s right to collective self-determination are not mutually exclusive positions. Another way to put my argument is that if collective self-determination matters morally, then the only way to guarantee that choices are made collectively is by guaranteeing everyone’s rights required to exercise collective self-determination within that society.

One conclusion of my argument is surprising: Walzer’s argument is incoherent because protecting some individual human rights is required to exercise collective self-determination. Walzer cannot explain why severe human rights abuses that impede individuals from contributing to collective decision making that do not rise to the level of genocide, mass atrocities, slavery, or ethnic cleansing, would not undermine collective self-determination. He could make an argument that a subset of a collective is all that is needed for collective self-determination, but he does not do so explicitly, and as I showed it would be difficult to justify how a subset of a collective is morally or logically equivalent to a whole collective.

Another important conclusion of my argument is that collective self-determination has intrinsic limits. Specifically, collective self-determination is undermined whenever, and to the extent that, individuals’ human rights are violated that impede them from contributing to collective choices. Powerful politicians making claims of collective self-determination for self-interested reasons cannot use this justification as a shield to commit severe human rights abuses. More precisely, the number of severe human rights violations of the relevant types is one measure of to what extent collective self-determination is undermined.

We can now apply my argument to a controversial case, NATO’s military intervention in Libya in 2011. Michael Walzer argued against the intervention for several reasons (Walzer 2011). One seems to include that the just cause was not met. He wrote, “a military attack of the sort now in progress is defensible only in the most extreme cases. Rwanda and Darfur, where we didn’t intervene, would have qualified. Libya doesn’t.” On my account, however, Walzer should have sided with those who countenanced intervention if it were proportionate because Qaddafi unjustly killed numerous innocent Libyans and credibly claimed that he would kill more. These unjust deaths undermined Libyans’ collective self-determination. Notice that this argument is not based on whether Qaddafi would have committed mass atrocities. Qaddafi and his military need not have committed or credibly threatened to commit mass atrocities for the just cause for intervention, even on Walzer’s terms.

The Libya intervention highlights another aspect of my argument, namely how the justification for the just cause of humanitarian intervention provides guidance not only on whether an intervention is permissible, but also on how an intervention should be executed. If NATO officials could have protected more lives of innocents by putting troops who volunteered for the mission on the ground – including counting the unjust deaths of innocent intervening troops – they should have done so in order protect more innocents and allow for greater collective self-determination. Whether one believes that collective self-determination or human rights are generally more important, this would have been the preferable policy.


  1. 1.

    I exclude discussion of a third, amoral strand of realism, because I am interested in the morality of intervention.

  2. 2.

    For a view on why democracy requires the protection of certain individual rights, see (Beetham 1999).

  3. 3.

    Wellman’s ideas about state legitimacy seem to have evolved between his 2009 book that he co-authored with Altman and his 2012 single authored article.

  4. 4.

    Monty Marshall and Keith Jaggers, “Polity IV Data,” 2010.

  5. 5.

    An exception to the impermissibility of intentionally targeting just intervening soldiers is when intervening soldiers violate jus in bello rules. For instance, if a fighter pilot who is on the side with a just cause sought revenge for a colleague’s death by intentionally targeting an apartment building in which everyone in it is innocent, it would be permissible for the unjust combatant to intentionally target the pilot. Innocent civilians who would be killed by just combatants as an unintentional although foreseeable result of a just war might also permissibly defend themselves against the just combatants. See respectively, McMahan, Killing in War, 16 and section 2.1.

  6. 6.

    Walzer allows the intentional targeting of civilians who are involved in efforts that are exclusively involved in war such as building tanks, but not duel use products such as food because food can feed soldiers or civilians (Walzer, Just And Unjust Wars, 145–146.).

  7. 7.

    Some of these would technically not be interventions because they have the consent of the target state. The typical justification for intervention of saving innocents’ lives is also contestable; the US government generally justifies them by arguing it keeps Americans safer than they would be without such strikes.

  8. 8.

    For a similar method of argument, see (Christiano 2011).


  1. Altman A, Wellman C (2009) A Liberal Theory of International Justice. Oxford University Press, USA

  2. Annan K (1999) Two Concepts of Sovereignty. The Economist.

  3. Beetham D (1999) Democracy and Human Rights, 1st edn. Polity

  4. Beitz C (1980) Nonintervention and communal integrity. Philos Public Aff 9(4):385–391

    Google Scholar 

  5. Beitz C (2001) Human rights as a common concern. Am Polit Sci Rev 95(2):269–282

  6. Beitz C (2009) The moral standing of states revisited. Ethics Int Aff 23(4):325–347. doi:10.1111/j.1747-7093.2009.00227.x

  7. Bellamy A (2011) Global Politics and the Responsibility to Protect: From Words to Deeds. Routledge, New York

  8. Christiano T (2011) An instrumental argument for a human right to democracy. Philosophy & Public Affairs 39(2):142–176. doi:10.1111/j.1088-4963.2011.01204.x

    Article  Google Scholar 

  9. Cohen J (2006) Is There a Human Right to Democracy? In: C Sypnowich (ed) The Egalitarian Conscience: Essays in Honour of G. A. Cohen. Oxford University Press, USA, 226–48

  10. Doyle M (2009) A few words on mill, walzer, and nonintervention. Ethics Int Aff 23(04):349–369. doi:10.1111/j.1747-7093.2009.00228.x

    Article  Google Scholar 

  11. Dworkin R (1984) Rights as Trumps. In: Waldron J (ed) Theories of Rights. Oxford University Press, USA, pp 153–167

    Google Scholar 

  12. Evans G, Sahnoun M, Côté-Harper G, Hamilton L, Ignatieff M, Lukin V, Naumann K, et al. (2001) The Responsibility to Protect: The Report of the International Commission on Intervention and State Sovereignty. IDRC Books: Ontario

  13. Fabre C (2012) Cosmopolitan War. Oxford University Press, USA

  14. Frowe H (2010) A practical account of self-defence. Law Philos 29(3):245–272. doi:10.1007/s10982-009-9062-1

    Article  Google Scholar 

  15. Frowe H (2011) The Ethics of War and Peace: An Introduction. Routledge

  16. Goodin R (2007) Enfranchising all affected interests, and its alternatives. Philos Public Aff 25:40–68

    Article  Google Scholar 

  17. Hurka T (2005) Proportionality in the morality of war. Philos Public Aff 33(1):34–66

  18. Hurka T (2008) Proportionality and Necessity. In: L May (ed) War: Essays in Political Philosophy. Cambridge University Press, 127–44

  19. Luban D (1980a) Just war and human rights. Philos Public Aff 9(2):160–181

    Google Scholar 

  20. Luban D (1980b) The romance of the nation-state. Philos Public Aff 9(4):392–397

    Google Scholar 

  21. Manza J, Uggen C (2006) Locked Out: Felon Disenfranchisement and American Democracy. Oxford University Press, USA

    Google Scholar 

  22. Mapel DR (2010) Moral liability to defensive killing and symmetrical self-defense. J Polit Philos 18(2):198–217. doi:10.1111/j.1467-9760.2009.00340.x

    Article  Google Scholar 

  23. McMahan J (1994) Innocence, self-defense and killing in war. J Polit Philos 2(3):193–221. doi:10.1111/j.1467-9760.1994.tb00021.x

    Article  Google Scholar 

  24. McMahan J (1996) Intervention and collective self-determination. Ethics Int Aff 10(1):1–24. doi:10.1111/j.1747-7093.1996.tb00001.x

    Article  Google Scholar 

  25. McMahan J (2005) The basis of moral liability to defensive killing. Philos Issues 15(1):386–405. doi:10.1111/j.1533-6077.2005.00073.x

    Article  Google Scholar 

  26. McMahan J (2009) Killing in War, 1st edn. Oxford University Press, Oxford

  27. McMahan J (2010) Humanitarian Intervention, Consent, and Proportionality. In: Davis A, Keshen R, McMahan J (eds) Ethics and Humanity: Themes from the Philosophy of Jonathan Glover. Oxford University Press, New York

  28. Orwell G (1945) Politics and the English Language. In: Essays. Everyman’s Library, pp. 954–67

  29. Pattison J (2010) Humanitarian Intervention and the Responsibility To Protect: Who Should Intervene? Oxford University Press, USA

  30. Philpott D (2001) Revolutions in Sovereignty: How Ideas Shaped Modern International Relations. Princeton University Press

  31. Pogge T (2003) Preempting Humanitarian Interventions. In: Jokic A (ed) Humanitarian Intervention: Moral and Philosophical Issues. Broadview Press, Peterborough, pp. 93–108

  32. Quong J (2012) Liability to defensive harm. Philos Public Aff 40(1):45–77. doi:10.1111/j.1088-4963.2012.01217.x

    Article  Google Scholar 

  33. Rawls J (1999) The Law of Peoples: With “The Idea of Public Reason Revisited”, 1st edn. Harvard University Press

  34. Rodin D (2002) War and Self-Defense. Oxford University Press, USA

  35. Rodin D (2014) Rethinking Responsibility to Protect: The Case for Human Sovereignty. In: D E Scheid (ed) The Ethics of Armed Humanitarian Intervention. Cambridge University Press, 243–60

  36. Walzer M (1973) Political action: the problem of dirty hands. Philos Public Aff 2(2):160–180

    Google Scholar 

  37. Walzer M (1977 [2000]) Just And Unjust Wars: A Moral Argument With Historical Illustrations, 3rd edn. Basic Books

  38. Walzer M (1980) The moral standing of states: a response to four critics. Philos Public Aff 9(3):209–229

    Google Scholar 

  39. Walzer M (2007) The Argument About Humanitarian Intervention. In: Miller D (ed) Thinking Politically: Essays in Political Theory. Yale University Press, New Haven, pp. 237-250

  40. Walzer M (2011) The Wrong Intervention. Dissent Magazine.

  41. Wellman C (2012) Debate: taking human rights seriously. J Polit Philos 20(1):119–130. doi:10.1111/j.1467-9760.2011.00407.x

    Article  Google Scholar 

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Aloyo, E. Reconciling Just Causes for Armed Humanitarian Intervention. Ethic Theory Moral Prac 19, 313–328 (2016).

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  • Humanitarian intervention
  • Just war theory
  • Collective self-determination
  • Human rights
  • Sovereignty
  • Just cause