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On the inevitability of divided government and improbability of a complete separation of powers


This paper provides a tightly written overview and modest extension of the constitutional exchange and evolution model developed in Perfecting Parliament and uses that approach to analyze the division of authority that one would expect to see in contemporary constitutional governments. The analysis suggests that constitutions tend to be written, based on the king and council template, and buttressed by a more or less independent court system. Moreover, it suggests that constitutions change at the margin through time as constitutional bargaining takes place. This suggests that a complete separation of power is unlikely to be observed in the long run. Empirical evidence developed from the IAEP data base is consistent with these predictions.

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  1. See Vile (1968) for an excellent intellectual history of normative theories of the separation of powers doctrine from the sixteenth century through the post-World War II period. See Buchanan and Tullock (1962) for the classic rational choice-based analysis of the constitutional architecture of the United States. Congleton (2011a, b) suggests that the American division reflects both liberal constitutional theory and a century of constitutional experimentation in the British colonies.

  2. Congleton (2011a, chaps. 5–6) provides a more technical analysis of bargaining over veto and agenda control in a setting of exogenous shocks—an analysis that persons who are skeptical of the Edgeworth box representation of constitutional exchange should consult. It shows how changes in circumstances (initial conditions and/or probability distributions) may change policies and also interests in bargaining over policy-making authority.

  3. In the two-person case, this analogy is less perfect, because whichever person has more than half the shares would control a company if it used majority rule. Thus, only four assignments of authority are possible in two firms in which shares are divided between two persons, and only two of that involve sharing overall authority. The analytics of divided authority can be very complex. See Congleton (2011a, b) for an effort to characterize how assignments of veto power and agenda control might be exchanged.

  4. See Voigt (1999) and Congleton (2011a, b) for a variety of historical illustrations in which political authority was altered through constitutional bargaining.

  5. Bargaining itself might also be analyzed, as with a Tullock success function or Nash bargaining game. Such an analysis would, however, only partly characterize the stochastic path of divided authority that tends emerge through time as exogenous shocks are experienced. Alternative theories of bargaining and amendment could then be tested using fine-grained constitutional time-series data, although it would be the shocks as much as the bargaining that determine the course of constitutional development.

  6. Indeed, the necessity of sleep would make holding on to power by oneself, even with very loyal slaves, exceedingly difficult.

  7. The actual exercise of authority, however, does require the use of scarce resources, including physical ones as well as what might be called psychological and sociological ones.

  8. Congleton (2011a) provides a good deal of historical evidence that Western democracy emerged from such bargaining.

  9. It bears noting that a constitutional court can also violate its constitution. For example, it can (indirectly) transfer authority to the judicial domain from the legislative and executive domains by both blocking legislation and expanding its jurisdiction (as arguably occurred with Marbury v. Madison [1803] in the United States, and many times afterward).

  10. An interesting constitutional device for escaping from constitutional constraints was developed by Saddam Hussein, who modified the pre-existing constitution of Iraq to exempt the highest office (himself)) from constitutional constraints. Article 38c of the 1990 constitution grants the Revolutionary Command Council the authority for “Accusing and prosecuting members of the Revolutionary Command Council, Vice-Presidents, and Ministers.” Note that the president is not so constrained by the council under the 1990 constitution. ( Not surprisingly, there was no supreme court in Iraq under the 1990 constitution. It was otherwise a fairly liberal constitution.

  11. The piecemeal creation of federations and confederations, as opposed to “whole cloth” constitutional design, is historically more common than the reverse. Historically, most towns had their own governments and these had been “glued” together through confederal contracts, treaties, conquest and the threat of conquest, and marriages (in Europe). As a result many decentralized systems have different starting points and different initial divisions of authorities between the central and local governments.

    Nonetheless, even in autocracies, most towns have some independent authority to write and enforce their own laws, although those laws cannot ordinarily overturn those of “higher” levels of government. (This is essentially what the term “higher level” means in most cases.) Historically, the extent of local authority varies by country and place, partly because of differences in starting points but also because different quasi-constitutional bargains have been struck through time.

  12. A useful rule of thumb for welfare-enhancing decentralization is the principle of subsidiarity embodied in Article 5(3) of the Treaty on European Union. Paraphrasing slightly, it can be written as follows:

    The [central government] shall act only if and insofar as the objectives of the proposed action cannot be sufficiently achieved by the Member States, either at the central level or at the regional and local level, but can rather, by reason of the scale or effects of the proposed action, be better achieved at [the central government] level.

    In many cases, however, the central government is constitutionally advantaged in these exchanges (through various superiority clauses and a broader tax base), which tends to promote the gradual centralization of policymaking authority beyond that recommended by economic analysis.

  13. The estimated coefficient for the interaction between executive ability to propose amendments and age of constitution is less accurately estimated than the interaction between legislature ability to propose amendments and constitutional age. Introducing these two interaction terms caused the value for authority of the legislature to cease being significantly different from zero. Dropping that variable and the also insignificant dictator variable caused the interaction term between executive authority to propose amendments and constitutional age to become statistically significant.


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Correspondence to Roger D. Congleton.

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Thanks are owed to many of the participants of the European Center for the Study of Public Choice conference held at the Walter Eucken Institute in Freiburg, Germany, in May 2013 for a variety of useful comments, although they bear no responsibility for the effect of their comments and advice on the content of this paper.

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Congleton, R.D. On the inevitability of divided government and improbability of a complete separation of powers. Const Polit Econ 24, 177–198 (2013).

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