Legal literature on traditional blockade law is abundant on the requirements of how to establish a blockade and what the consequences for a vessel are when it is in violation.Footnote 60 It also emphasizes that when the requirements for establishing a blockade are not met, it is considered to be non-binding upon neutral Sates. In this situation, a belligerent state cannot make any use of the authorities based on the law of blockade. What exactly would render a blockade unlawful is, however, a more complex issue, especially when seen from the perspective of the modern law of blockade. In the following paragraphs I will consider three possible ways in which a blockade could be determined to be unlawful: Unlawfulness under traditional law, via a breach of humanitarian law and via a breach of the principles of the laws of war.
At first sight the traditional law seems quite clear on when a blockade is considered to be unlawful. If one of the requirements of notification or effectiveness is not met, a blockade can be considered non-binding upon neutral states.Footnote 61 The technical requirement of notification is rather straight forward and easy to determine. But the debate obviously lies in the vagueness of the term ‘effective’. As Heinegg mentions, ‘there are no criteria that would make possible an abstract determination of the effectiveness of all blockades’ (Heintschel von Heinegg 2006). Considering a blockade non-binding based on this requirement seems therefore difficult to establish and without an international court decision it would be hard to impose such a position on the blockading belligerent. Smith recalls a historical case in 1861 when the whole coast of the Confederate States of some 3,000 miles was blockaded by 45 ships and around 50 armed merchantmen of the United States. Although it was clear that the blockade was not effective, no neutral power contested it and the United States Supreme Court judged the blockade to be effective (Smith 1950). According to Verzijl there were ten “regular” blockadesFootnote 62 established during the First World War against which no claims of ineffectiveness were ever raised.Footnote 63
Although the London Declaration does not explicitly attach consequence to the non-fulfillment of the principle of impartiality,Footnote 64 different authors referring to national prize courtsFootnote 65 and military manuals regard impartiality as a condition.Footnote 66 Section 100 SRMFootnote 67 reiterates the rule of article 5 of the London Declaration on impartially, but it fails to mention whether or not it renders a blockade unlawful. A neutral state against who the principle is not adhered to will have the ability to complain to the belligerent. Such a complaint, however, gives rise to another issue, as a claim of a State that is of the opinion that the blockade is unlawfully established will not render the blockade automatically unlawful for the complaining State or any other neutral state. The mere claim may be legally correct and politically and internationally widely supported, but does not overrule a decision of another State. What is required is the determination of the issue by an independent body whose decision is binding upon all of the parties. This is further enshrined in the principle of impartiality.
Verzijl opines also that a breach of article 1 of the London DeclarationFootnote 68 will render a blockade unlawful because it lies in the very nature of the term ‘blockade’ that it is established against an enemy.Footnote 69 Blockades established against States that cannot be considered as such must be considered as unlawful. He furthermore argues that the difference with article 18 of the London Declaration, which states that blockading forces must not bar the access to neutral ports or coasts, is that the blockade in the latter situation is not purposely directed against the neutral state but by its enforcement factually also closes a neutral port or coast. Although it is a breach of a provision of the law of blockade, it does not render the blockade itself null and void as a whole.
Unlawfulness of a blockade via a breach of humanitarian law
Using a blockade as a method of warfare runs the risk of breaching humanitarian law. The naval blockade can be the sole cause or aggravate the circumstances of the breach. It could, for instance, result in there being a shortage of food, medical and other essential supplies, that, if the conditions mentioned in for instance 23 GC IV, 59 GC IV or 70 APIFootnote 70 are not met and/or no sufficient relief to the civilian population is given, may render the blockading party in breach of these articles. Seen from a modern law of blockade perspective that includes humanitarian law as a factor when considering the unlawfulness of a blockade, the question arises as to whether or not a breach of humanitarian law will also render the blockade unlawful.
There are no provisions within Geneva law that explicitly render a blockade unlawful if it is breached. But, as said above, legal literature usually does make a link between article 54 API that forbids starvation as a method of warfare and blockades (Heintschel von Heinegg 1992). In this respect the ICRC-commentary on article 54 API seems to differentiate between the intention and the result of the blockade. If starvation is the purpose of establishing the blockade, it breaches article 54 API. When a blockade has starvation as a result it triggers relief actions or could even lead to the evacuation of such persons, under article 17 GC IV (Sandoz et al. 1987). The ICRC-commentary does not, however, conclude that in this situation the blockade becomes unlawfully established, but it merely mentions the uncertain present state of the laws of naval warfare.
The same view with regard to the link between starvation and blockade is adopted by the SRM. The SRM also explicitly notes the consequences for an established blockade. Paragraph 102 SRM states that the establishment of a blockade for the sole purpose of starving the civilian population is prohibited. In line with the ICRC commentary this paragraph deals with the intention of the blockade and not with its consequences, or as the SRM-explanation says, its side-effectsFootnote 71: ‘Whenever the blockade has starvation as one of its effect, the starvation effectively triggers the obligation, subject to certain limitations, to allow relief shipping to gain access to the coasts of the blockaded belligerent’.Footnote 72 This view is reflected in paragraph 103 and 104 SRM that is concerned with the results of the blockade and creates a duty to relieve the population of a blockaded area. A more practical argument as to why this situation would not render the blockade unlawful is that the choice of measures that are open to a belligerent to resolve the situation aside from lifting the blockade are numerous. If a belligerent can take measures that would address the violation while still enforcing the blockade, one can argue that it remains lawfully established. If it is for instance possible to allow the ingress of essential foodstuff by air and land to sufficiently address the deteriorating humanitarian situation, or alter the enforcement of the blockade with regards to allowing certain goods in, there is no ground to consider the naval blockade unlawful.Footnote 73 The SRM’s view towards potential unlawfulness of a blockade when its purpose is starvation is supplemented by the ICRC study on customary international humanitarian law (2005) which considers that the principle has the status of customary law (Henckaerts and Doswald-Beck 2005). It points out that siege warfare is forbidden if the purpose is to starve a civilian population, but not prohibited if the purpose is to achieve a military objective. It also specifically emphasizes that this principle also applies in the use of naval blockades and embargoes. In summary, breaches of particular provisions of humanitarian law with regard to the civilian population caused by a blockade create an obligation for the belligerent to take action to remedy the situation, but do not necessarily render the blockade unlawful, unless its purpose is to starve the blockaded population. As such, it appears that in principle it is accepted that a breach of humanitarian law can have an effect on the lawfulness of a blockade. In this respect it is interesting to mention the conclusions of the Hudson-Philips report and the Turkel-Commission.
Collective punishment: the Hudson Philips-report
The Hudson-Philips report takes a step further with regard to the already accepted norms for unlawfulness of a naval blockade. The Hudson-Philips Mission first of all draws the conclusion that the humanitarian situation in the Gaza is such that the laws of war are breached. The Mission classifies Israel’s closure of Gaza that resulted in the grave humanitarian situation as collective punishment of the civilian population, which is prohibited according to article 33 GC IV.Footnote 74 This article states that:
No protected person may be punished for an offence he or she has not personally committed. Collective penalties and likewise all measures of intimidation or of terrorism are prohibited.
Pillage is prohibited.
Reprisals against protected persons and their property are prohibited.
Although Israel argues that the purpose of establishing the blockade lies in reasons of security,Footnote 75 paragraph 54 of the report rejects this argument and mentions that: ‘The Mission considers that one of the principal motives behind the imposition of the blockade was a desire to punish the people of the Gaza Strip for having elected Hamas. The combination of this motive and the effect of the restrictions on the Gaza Strip leave no doubt that Israel’s actions and policies amount to collective punishment as defined by international law’.
A similar statement that article 33 GCIV is breached in the Gaza situation was made earlier by the ICRC. The ICRC condemned the closure of Gaza in a statement as a war crime: ‘The whole of Gaza’s civilian population is being punished for acts for which they bear no responsibility. The closure therefore constitutes a collective punishment imposed in clear violation of Israel’s obligations under international humanitarian law’.Footnote 76 In this statement the ICRC does however not specifically refer to the naval blockade that was established in 2009, but refers to the closure of Gaza as a whole that ‘is about to enter its fourth year’. The report then goes on to conclude that the naval blockade was established in support of the overall closure regime that must be regarded as disproportionate, and thus also becomes illegally established. In addition to the view that the blockade is a disproportionate measure, it adds that the closure regime, of which the naval blockade is part, constituted collective punishment for the civilian population:
60. Furthermore, the closure regime is considered by the Mission to constitute collective punishment of the people living in the Gaza Strip and thus to be illegal and contrary to article 33 of the Fourth Geneva Convention.
Apart from judging the naval blockade through the principle of proportionality, the Mission appears to have also created a new ground to render a blockade unlawful by referring to article 33 GC IV: when a naval blockade is part of the breach of article 33 GC IV the blockade must be seen as unlawfully established. Finally, the Mission concludes that as a consequence of the unlawfulness of the blockade the military actions against the Mavi Marmara were therefore also unlawful:
261. The Mission considers that the enforcement of an illegal blockade does not only constitute a violation of the laws of war, but also a violation of the laws of neutrality giving rise to State responsibility.
262. Certain results flow from this conclusion. Principally, the action of the Israel Defense Force in intercepting the Mavi Marmara on the high seas in the circumstances and for the reasons given was clearly unlawful. Specifically, the action cannot be justified in the circumstances even under Article 51 of the Charter of the United Nations.
The Turkel-commission is very detailed on the issue of naval blockade. In its findings the commission is supported by two ‘special consultants’; Wolff Heintschel von Heinegg and Michael Schmitt. In paragraphs 56–97 the issue of the naval blockade and its compliance with the law of blockade is discussed. Clearly the Commission takes the traditional law requirements as its central point of departure. It also considers humanitarian aspects to the law of naval blockade, but only as far as the provisions that are already considered as being a part of the modern law of blockade and mentioned in the SRM. Although it briefly considers the application of human rights, it is however reluctant to view the law of blockade from a wholly humanitarian perspective that reflects the complete scope of humanitarian law.
Contrary to the Hudson-Philips report the Turkel report pays more in-depth attention to the requirements under traditional blockade law. It discusses first its compliance with the traditional law of blockade and secondly discusses the modern humanitarian aspects of the law of blockade. With regard to the traditional law the overall conclusion is that Israel complied with the requirements of effectiveness, impartiality and notification.Footnote 77 The report also gives an interesting insight into what action Israel has taken to fulfill the requirement of notification.
With regard to the modern (humanitarian) aspects of the law of blockade the report is guided by sections 102–104 SRM: ‘Once a blockade is established, it is likely to have a humanitarian impact on the civilian population in the blockaded area. The blockading party must therefore consider the humanitarian impact that the blockade will have on the civilian population of the territory’.Footnote 78 Also on the humanitarian aspects the report concludes, similar to the their analysis on the issue of relief actions,Footnote 79 that the steps taken by Israel during the naval blockade are ‘consistent with customary international law as provided in articles 102(a) and 103 of the San Remo Manual’.Footnote 80
Because the Turkel report was published later than the Hudson-Philips report, it had the opportunity to comment on the views expressed by the Hudson-Philips Mission, specifically on the view of collective punishment, which is the main argument in the Hudson-Philips report against their being a lawfully established blockade. In paragraph 107 the Turkel Commission reaches the following conclusion with regard to collective punishment and the law of blockade:
107. As for the naval blockade itself, within the framework of the rules that govern the imposition and enforcement of such a blockade, there is no basis for an allegation of ‘collective punishment.’ There is nothing in the Red Cross’ Customary International Law Study that in any way connects the idea of ‘collective punishment’ with a naval blockade or siege warfare On the contrary, the Study states that ‘the prohibition of starvation as a method of warfare does not prohibit the imposition of a naval blockade as long as the purpose is to achieve a military objective and not to starve a civilian population.Footnote 81
The Turkel-Commission, contrary to Hudson-Philips, thereby takes a more restrictive view of the rendering a blockade unlawful through provisions of humanitarian law and is apparently of the opinion that the current law of blockade is limited to the already accepted intertwinements of humanitarian law with the law of blockade that are mentioned in the SRM. The Commission considered that other provisions of humanitarian law do not affect the legality of a blockade. A breach of article 33 GCIV is said to be outside of this scope and cannot therefore lead to the determination of a naval blockade being unlawful.
Unlawfulness via a breach of the principles of the law of armed conflict
Doswald-Beck mentions, while discussing the development of international law in the maritime dimension and the need for a revision of the traditional laws of naval warfare, that: ‘Furthermore, all aspects of armed conflict should be in conformity with the basic principles of international humanitarian law, wherever the theatre of operations might be’ (Doswald-Beck 1995c, p. 585). Although strictly not necessary, the SRM has incorporated the principle of proportionality into the law of blockade in section 102b. If the blockade cannot be considered proportional in relation to the concrete and direct military advantage anticipated from the blockade, its establishment is prohibited. The Turkel Commission takes note of the disputed customary status of this rule by the Israeli Military Advocate General,Footnote 82 but argues that even without a specific rule the principle of proportionality remains a principle that must be taken into account. The arguable difference would be that whether or not a blockade would become illegal is less explicit, but even if all the requirements of the (traditional) law are adhered to it still renders the blockade unlawful when the blockade is excessive in relation to the military advantage anticipated from the blockade. In the flotilla incident case both the view that the blockade was proportionate and disproportionate are taken.
The Hudson-Philips report stated that proportionality is a requirement for a legally established blockade. In paragraph 53 the Mission mentions that: ‘In evaluating the evidence submitted to the Mission …[…]… confirming the severe humanitarian situation in Gaza, the destruction of the economy and the prevention of reconstruction (as detailed above), the Mission is satisfied that the blockade was inflicting disproportionate damage upon the civilian population in the Gaza strip and that as such the interception could not be justified and therefore has to be considered illegal’. As a conclusion the Mission underlines that:
59. The Mission finds that the policy of blockade or closure regime, including the naval blockade imposed by Israel on Gaza was inflicting disproportionate civilian damage. The Mission considers that the naval blockade was implemented in support of the overall closure regime. As such it was part of a single disproportionate measure of armed conflict and as such cannot itself be found proportionate.
With regard to the question of proportionality the Turkel report seeks to underline several factors that need to be taken into account when assessing proportionality. As a start the commission underlines the obligation not to cause excessive damage.Footnote 83 With regard to military advantage, the commission is persuaded that if not for the blockade, Hamas could have replenished its weapons and increased its attacks on Israel by the sea, but notably the attacks have significantly decreased.Footnote 84 It furthermore finds it necessary for the proportionality debate to compare the blockade with the economic sanctions imposed against Iraq in 1990, to show that the civilian population inherently suffers during economic sanctions, that although caused debate but was not condemned.Footnote 85 Finally, it underlines that Israel has put in place mechanisms on the land borders that intends to regulate goods entering the Gaza.Footnote 86 In conclusion:
The Commission has therefore reached the conclusion that Israel is in compliance with the requirement of proportionality provided in international humanitarian law, especially in view of the extensive steps that it took recently in order to restrict the effects of the naval blockade and the land crossings policy on the population of the Gaza Strip.Footnote 87
More grounds for unlawfulness of blockades based on humanitarian law?
Until now the naval law discussion on the unlawfulness of a blockade via a breach of humanitarian law has concentrated on a few provisions of humanitarian law. Whether or not one accepts the arguments of the Turkel report or the Hudson-Philips report, the Hudson-Philips report does offer a new approach to the unlawfulness of blockades based on a provision of humanitarian law. One author writing on the Gaza conflict has already adopted the view that the Israeli blockade could result in there being a breach of provisions such as article 33 and 55 GCIV, but has not added as a conclusion that the blockade is therefore unlawful (Sterio 2010). Although the Hudson-Philips report does not solely base its conclusion on the breach of article 33 GCIV, it opens the way to the understanding that there may be other situations where provisions of humanitarian law actually will impact on the legality of a naval blockade. This however may represent the next step in the development of the modern law of blockade. Another step further is considering a blockade unlawful in the situation in which a belligerent willingly chooses not to address the violation to which the blockade is attributing or addresses it but fails to take sufficient steps. If no other means are sought to ‘justify’ the blockade, it could thereby become an unlawful method of war. Such a view appears to be taken in the recently drafted Manual for Air and Missile warfare (AMW)Footnote 88 in which the belligerent is given a choice to allow foodstuff through the aerial blockade or alternatively to lift the blockade.Footnote 89 The difficulty will obviously be that it will be hard to determine whether or not the belligerent has taken sufficient steps.