¹ Nine countries have majority rule and four qualified plurality since the 1998 constitutional reform in Ecuador.

² On the party system effects of electoral systems, see Maurice Duverger, Political Parties: Their Organization and Activity in the Modern State (New York: Wiley, 1963); William Riker, ‘Duverger’s Law Revisited’, in Bernard Grofman and Arend Liphart, eds, Electoral Laws and Their Political Consequences (New York: Agathon Press, 1986), pp. 19–42; Gary W. Cox, Making Votes Count: Strategic Coordination in the World’s Electoral Systems (Cambridge: Cambridge University Press, 1997).

³ Matthew S. Shugart and John M. Carey, President and Assemblies: Constitutional Design and Electoral Dynamics (New York: Cambridge University Press, 1992), p. 209; Mark Jones, Electoral Laws and the Survival of Presidential Democracies (Notre Dame, Ind.: University of Notre Dame Press, 1995).

⁴ For the purposes of this article, I count majority rule with congressional choice among the frontrunners and majority with run-off as the same rule. This is because they create similar electoral incentives among parties to field presidential candidates in the first round.

⁵ Mark Jones, ‘Electoral Laws and the Effective Number of Candidates in Presidential Elections’, Journal of Politics, 61 (1999), 171–84.

⁶ Gabriel Negretto, ‘Propuesta para una Reforma Electoral en México’, Política y Gobierno, 14 (2006), 215–27.

⁷ On average, below 3. See Matt Golder, ‘Presidential Coattails and Legislative Fragmentation’, American Journal of Political Science, 50 (2006), 34–48.

⁸ Since the nineteenth century, however, there have been some departures from this model. See Eduardo Aleman and George Tsebelis, ‘The Origins of Presidential Conditional Agenda Setting Power in Latin America’, Latin American Research Review, 40 (2005), 3–26.

⁹ The variation of veto powers within countries is generally lower across time than the variation of agenda powers. On the proactive role of presidents, see Gary W. Cox and Scott Morgenstern, ‘Epilogue: Latin America’s Reactive Assemblies and Proactive Presidents’, in Scott Morgenstern and Benito Nacif, eds, Legislative Politics in Latin America (Cambridge: Cambridge University Press, 2002).

¹⁰ Other important aspects of the electoral system, such as the rules for electing legislators, may be regulated by secondary laws.

¹¹ Adam Przeworski, Michael E. Alvarez, Jose Antonio Cheibub and Fernando Limongi, Democracy and Development: Political Institutions and Well-Being in the World, 1950–1990 (Cambridge: Cambridge University Press, 2000), p. 49.

¹² Arend Lijphart, ‘Constitutional Choices for New Democracies’, Journal of Democracy, 2 (1991), 72–84.

¹³ Bruce Ackerman, We the People (Cambridge, Mass.: Harvard University Press, 1991).

¹⁴ Jon Elster, ‘Forces and Mechanisms in Constitution-Making’, Duke Law Review, 45 (1995), 364–96.

¹⁵ One such constraint, for instance, is a high degree of electoral uncertainty at the time of choice.

¹⁶ Strategic explanations of constitutional choice include Barbara Geddes, ‘Initiation of New Democratic Institutions in Eastern Europe and Latin America’, in Arend Lijphart and Carlos Waisman, eds, Institutional Design in New Democracies: Eastern Europe and Latin America (Boulder, Colo.: Westview Press, 1996), pp. 15–41; Arend Lijphart, ‘Democratization and Constitutional Choices in Czecho-Slovakia, Hungary and Poland 1989–91’, Journal of Theoretical Politics, 4 (1992), 207–23; Elster, ‘Forces and Mechanisms in Constitution-Making’; Timothy Frye, ‘A Politics of Institutional Choice: Post Communist Presidencies’; Comparative Political Studies, 30 (1997), 523–52; Matthew S. Shugart, ‘The Inverse Relationship Between Party Strength and Executive Strength: A Theory of Politicians’ Constitutional Choices’, British Journal of Political Science, 28 (1998), 1–29; Josep Colomer, Strategic Transitions: Game Theory and Democratization (Baltimore, Md.: The Johns Hopkins University Press, 2000).

¹⁷ On the distinction between redistributive and efficient institutions, see George Tsebelis, Nested Games (Berkeley: University of California Press, 1995).

¹⁸ Gabriel L. Negretto, ‘Choosing How to Choose Presidents: Parties, Military Rulers, and Presidential Elections in Latin America’, Journal of Politics, 68 (2006), 421–32.

¹⁹ On the different levels of constitutional choice, see Calvin Jillson, Constitution-Making: Conflict and Consensus in the Federal Convention of 1787 (New York: Agathon Press, 1988).

²⁰ See Gabriel Negretto, ‘The Durability of Constitutions in Changing Environments: Explaining Constitutional Replacements in Latin America’, Kellogg Institute, Working Paper No. 350 (2008).

²¹ See Bernard Grofman and Andrew Reynolds, ‘Electoral Systems and the Art of Constitutional Engineering: An Inventory of the Main Findings’, in Ram Mudambi et al., eds, Rules and Reason: Perspectives on Constitutional Political Economy (Cambridge: Cambridge University Press, 2001), pp. 125–64.

²² Most of the cases of constitution making I analyse occur in relatively stable political environments, where political parties have a recognizable identity and well-defined interests. The assumption is less justified in some transitional contexts, particularly in constitutional foundings.

²³ Steven J. Brams, Negotiation Games: Applying Game Theory to Bargaining and Arbitration (New York: Routledge, 1990).

²⁴ On this point, see Geddes, ‘Initiation of New Democratic Institutions’, and Frye, ‘A Politics of Institutional Choice’.

²⁵ Shugart, however, argues that rank-and-file party members in a constituent assembly prefer to delegate legislative power to either the president or national party leaders, depending on whether they cultivate personal reputations or a collective party reputation to win elections. His argument does not consider whether delegates belong to the party of the president or to opposition parties. See Shugart, ‘The Inverse Relationship Between Party Strength and Executive Strength’, p. 8.

²⁶ See Shugart, ‘The Inverse Relationship Between Party Strength and Executive Strength’.

²⁷ See Appendix B for data sources.

²⁸ Of course, the number of amendments unrelated to the revision of any of these dimensions of design is much larger than those considered here.

²⁹ Decision rules range from simple to qualified majority, sometimes including additional instances of approval, such as referendums.

³⁰ Shugart and Carey, President and Assemblies, chap. 8.

³¹ For a comparison between Shugart and Carey’s index and other measurements of presidential power, see Lee K. Metcalf, ‘Measuring Presidential Power’, Comparative Political Studies, 33 (2000), 661–85.

³² Another limitation is that the scale used to measure and compare different powers is not always consistent. Sometimes the scale does not exhaust all possible combinations. Decree power, for instance, is measured according to whether this instrument is subject to restrictions. Decrees, however, can be restricted in several, not mutually exclusive dimensions. There are also problems with the quantification of the scale. Sometimes the addition of a variable increases the scale by one unit (0–1–2–3–4), sometimes by two units (0–2–4). This complicates the comparison of scores across powers.

³³ John Carey and Mathew Shugart, eds, Executive Decree Authority (New York: Cambridge University Press, 1998); Gabriel Negretto, ‘Government Capacities and Policy-Making by Decree in Latin America: The Cases of Brazil and Argentina’, Comparative Political Studies, 37 (2004), 531–62.

³⁴ On principal component analysis, see Brian Everitt and Graham Dunn, Applied Multivariate Data Analysis (London: Edward Arnold, 2001).

³⁵ Since the coding consists of only dummy and ordinal variables, I have used a variant of PCA explicitly designed for categorical variables. The main difference between PCA and this variant, called categorical principal component analysis (CATPCA), is that the latter does not assume a linear relationship between each unit of the scale used to measure each power. See J. J. Meulman, A. J. Van der Kooij and W. J. Heiser, ‘Principal Components Analysis with Nonlinear Optimal Scaling Transformations for Ordinal and Nominal Data’, in D. Kaplan, ed., Handbook of Quantitative Methodology for the Social Sciences (Thousand Oaks, Calif.: Sage Publications, 2004), pp. 49–72.

³⁶ See Everitt and Dunn, Applied Multivariate Data Analysis, p. 48.

³⁷ The original scale has both negative and positive scores, with a mean of 0 and a standard deviation of 1.

³⁸ The correlation is just 0.42 with PCA and 0.46 with the interactive index.

³⁹ The formula is calculated here as 1 divided by the sum of the squares of the fractions representing the respective shares of the seats won by each party in the constituent assembly or in the lower or single chamber of a constituent congress. See Markku Laakso and Rein Taagepera, ‘Effective Number of Parties: A Measure with Application of Western Europe’, Comparative Political Studies, 12 (1979), 3–27.

⁴⁰ See Scott Mainwaring and Timothy Scully, eds, Building Democratic Institutions: Party Systems in Latin America (Stanford: Stanford University Press, 1995), pp. 31–2.

⁴¹ Observed values of this variable in the dataset range from 1 to 5.

⁴² John Carey and Mathew Shugart, ‘Incentives to Cultivate a Personal Vote: A Rank Ordering of Electoral Formulas’, Electoral Studies, 14 (1995), 417–39; Gary W. Cox and Matthew D. McCubbins, ‘The Institutional Determinants of Economic Policy Outcomes’, in Stephan Haggard and Matthew D. McCubbins, Presidents, Parliaments and Policy (Cambridge: Cambridge University Press, 2001), pp. 21–63.

⁴³ Since local level politicians can control party lists, as is the case in Argentina and Mexico, closed lists can coexist with decentralized parties. To consider the impact of these variables, I tested two different specifications of partycentr, one maintaining the variable as dichotomous but coding closed lists controlled by local actors as 0, and another coding them, along with multiple closed lists, as an intermediate case (2) between open lists (1) and single closed lists under the control of national party leaders (3). The results were essentially the same as those reported in the paper. I thank an anonymous reviewer for pointing this out.

⁴⁴ Using enp in the constituent body shows results similar to those reported in the text.

⁴⁵ I could not disaggregate mnp further since all the cases with more than three parties were associated with majority rule (perfect prediction).

⁴⁶ I also measured this variable as the percentage of countries per sub-region (Southern, Andean, Central and North) that had majority rule for presidential elections the year before a constitution in another country in the same geographical area was amended or replaced. Results did not differ from those reported here.

⁴⁷ Calculated using the Spost program. See Scott J. Long and Jeremy Freese, Regression Models for Categorical Dependent Variables Using Stata (College Station, Tex.: Stata Press, 2001).

⁴⁸ Estimated probabilities are based on Michael Tomz, Jason Wittenberg and Gary King, CLARIFY: Software for interpreting and presenting statistical results, Version 2.1, 1/5/2003. Available at http://gking.harvard.edu/.

⁴⁹ Shugart and Carey, President and Assemblies; Jones, Electoral Laws and the Survival of Presidential Democracies.

⁵⁰ Results similar to those reported in the text are obtained when using the interactive qualitative index of legislative powers. With the Shugart and Carey’s index, however, the effect of partycentr is only marginally significant.

⁵¹ Using enp in the constituent body shows results similar to those reported in the text.

⁵² I thank one of the anonymous reviewers for pointing this out.

⁵³ If in addition to length we add a time variable, the effect of mnp slightly decreases while the impact of time becomes significant only for the decades after 1960. This shows that while the legislative powers of presidents have tended to increase in the last decades, the effect is not due to the expansion of constitutions over time.

⁵⁴ This effect is more perceptible if we disaggregate mnp into two, three and more than three parties.

⁵⁵ See Thomas Brambor, William Roberts Clark and Matt Golder, ‘Understanding Interaction Models: Improving Empirical Analyses’, Political Analysis, 14 (2006), 63–82.

⁵⁶ A president was considered to be strong when the score of legislative powers was above the mean of the database.

⁵⁷ Among the cases of constitutional change included in the database, the ENP was 2.1 (std. dev., 0.81) before 1978 and 3.5 (std. dev., 1.56) after that date.