¹ Michelle Kuenzi and Gina Lambright, ‘Party System Institutionalization in 30 African Countries’, Party Politics, 7 (2001), 437–68; Scott Mainwaring and Timothy Scully, ‘Party Systems in Latin America’, in Scott Mainwaring and Timothy Scully, eds, Building Democratic Institutions: Party Systems in Latin America (Stanford, Calif.: Stanford University Press, 1995), pp. 1–34; Giovanni Sartori, Parties and Party Systems (Cambridge: Cambridge University Press, 1976); H. E. Hale, ‘Why No Parties? Electoral Markets, Party Substitutes, and Stalled Democratization in Russia’, Comparative Politics, 37 (2005), pp. 147–66.

² Carles Boix, ‘The Emergence of Parties and Party Systems’, in Carles Boix and Susan Stokes, eds, Oxford Handbook of Comparative Politics (Oxford: Oxford University Press, 2007), pp. 499–521; Scott Mainwaring, Rethinking Party Systems in the Third Wave of Democratization: The Case of Brazil (Stanford, Calif.: Stanford University Press, 1999); Herbert Kitschelt, Zdenka Mansfeldova, Radoslaw Markowski and Gabor Toka, Post-Communist Party Systems: Competition, Representation, and Inter-Party Cooperation (Cambridge: Cambridge University Press, 1999).

³ Paul Pierson, ‘Increasing Returns, Path Dependence, and the Study of Politics’, American Political Science Review, 94 (2000), 251–67, p. 255.

⁴ John Gerring, Case Study Research: Principles and Practices (Cambridge: Cambridge University Press, 2007), pp. 50–3, 57–9.

⁵ Paul Pierson, ‘Not Just What, but When: Timing and Sequence in Political Processes’, Studies in American Political Development, 14 (2000), 72–92, p. 76.

⁶ Pierson, ‘Not Just What, but When’, pp. 76–7; Pierson, ‘Increasing Returns’, pp. 252–4.

⁷ Rein Taagepera and Matthew Soberg Shugart, Seats and Votes: The Effects and Determinants of Electoral Systems (New Haven, Conn.: Yale University Press, 1989), pp. 77–91.

⁸ Gary Cox, Making Votes Count: Strategic Coordination in the World’s Electoral Systems (Cambridge: Cambridge University Press, 1997), p. 7.

⁹ Kitschelt et al., Post-Communist Party Systems, pp. 19–42; Mainwaring, Rethinking Party Systems, pp. 63–88; Cox, Making Votes Count, pp. 203–37.

¹⁰ Kenneth Benoit, ‘Models of Electoral System Change’, Electoral Studies, 23 (2004), 363–89, p. 384; Alfred Stepan and Juan Linz, ‘Political Identities and Election Sequences: Spain, the Soviet Union, and Yugoslavia’, Daedalus, 121, no. 2 (1992), 123–39, G. M. Reich, ‘Coordinating Party Choice in Founding Elections: Why Timing Matters’, Comparative Political Studies, 34, no. 10 (2001), 1237–63; Kitschelt et al., Post-Communist Party Systems, pp. 19–42; Mainwaring, Rethinking Party Systems, pp. 63–88; Cox, Making Votes Count, pp. 203–37; Peter Ordeshook and Olga Shvetsova, ‘Ethnic Heterogeneity, District Magnitude, and the Number of Parties’, American Journal of Political Science, 38 (1994), 100–23.

¹¹ Jack Bielasiak, ‘Substance and Process in the Development of Party Systems in East Central Europe’, Communist and Post-Communist Studies, 30 (1997), 23–44, p. 28.

¹² Michael Laver and Kenneth Benoit, ‘The Evolution of Party Systems between Elections’, American Journal of Political Science, 47 (2003), 215–33.

¹³ Cox, Making Votes Count, pp. 181–202; John Aldrich, Why Parties? The Origins and Transformation of Party Politics in America (Chicago: University of Chicago Press, 1995); Pradeep Chhibber and Kenneth Kollman, The Formation of National Party Systems. Federalism and Party Competition in Canada, Great Britain, India and the United States (Princeton, N.J.: Princeton University Press, 2004).

¹⁴ Cox, Making Votes Count, pp. 41–2; George Tsebelis, Nested Games: Rational Choice in Comparative Politics (Berkeley: University of California Press, 1990), pp. 187–233; Olga Shvetsova, ‘Institutions and Coalition Building in Post-Communist Transitions’, in Andrew Reynolds, ed., The Architecture of Democracy (Oxford: Oxford University Press, 2002), pp. 55–76.

¹⁵ Cox, Making Votes Count, pp. 151–78; Johanna Kristin Birnir, ‘Public Venture Capital and Party Institutionalization’, Comparative Political Studies, 38, no. 8 (2005), 915–38.

¹⁶ Benoit, ‘Models of Electoral System Change’; Carles Boix, ‘Setting the Rules of the Game: The Choice of Electoral Systems in Advanced Democracies’, American Political Science Review, 93 (1999), 609–24.

¹⁷ Marcus Kreuzer and Vello Pettai, ‘Patterns of Political Instability: Affiliation Patterns of Politicians and Voters in Postcommunist Estonia, Latvia and Lithuania’, Studies in Comparative International Development, 38, no. 2 (2003), 73–95; Marcus Kreuzer and Vello Pettai, ‘Party Switching, Party Systems, and Political Representation’, in William Heller and Carole Mershon, eds, Political Parties and Legislative Party Switching (New York: Palgrave, 2009), pp. 165–86; Goldie Shabad and Kazimierz Slomczynski, ‘Interparty Mobility among Political Elites in Post-Communist East Central Europe’, Party Politics, 10 (2004), 151–76; Mainwaring, Rethinking Party Systems, pp. 131–74; Richard Gunther, ‘Electoral Laws, Party Systems, and Elites: the Case of Spain’, American Political Science Review, 83 (1989), 835–58.

¹⁸ Cox, Making Votes Count, pp. 149, 255. The importance of political actors in the formation of party systems has long been highlighted in the older party literature. See Giovanni Sartori, ‘From the Sociology of Politics to Political Sociology’, in Seymour Martin Lipset, ed., Politics and the Social Sciences (New York: Oxford University Press, 1969), pp. 65–100; E. E. Schattschneider, Party Government (Westport, Conn.: Greenwood Publications, 1970). Gary Cox’s great contribution has been to use game theory to demonstrate the inherent instability of party systems and to show how its absence is contingent on the way politicians’ successful co-ordination strategies structure voter expectations. In emphasizing politicians, Cox also avoids the indeterminacy of earlier attempts to model Duverger’s law which focused too narrowly on equilibrium solutions generated exclusively through institutional incentives, strategic interaction of voters, and quadrennial, electoral updating of their expectations. See also John Schieman, ‘Meeting Halfway Between Rochester and Frankfurt: Generative Salience, Focal Points, and Strategic Interaction’, American Journal of Political Science, 44 (2000), 1–16.

¹⁹ Anthony Downs, An Economic Theory of Democracy (New York: Harper and Row, 1957), pp. 77–114; William Riker, ‘Heresthetic and Rhetoric in the Spatial Model’, in James Enelow and Melvin Hinich, eds, Advances in the Spatial Theory of Voting (Cambridge: Cambridge University Press, 1990), pp. 46–63; Bonnie M. Meguid, ‘Competing Between Unequals: The Role of Mainstream Party Strategy in Niche Party Success’, American Political Science Review, 99 (2005), 347–59.

²⁰ Cox, Making Votes Count, pp. 203–21; Ordeshook and Shvetsova, ‘Ethnic Heterogeneity’.

²¹ Kitschelt et al., Post-Communist Party Systems, p. 19.

²² Rainer Lepsius, ‘Parteiensystem und Sozialstruktur: zum Problem der Demokratisierung der deutschen Gesellschaft’, in Gerhard A. Ritter, ed., Deutsche Parteien vor 1918 (Cologne: Kiepenheuer & Witsch, 1973), pp. 56–80.

²³ Marcus Kreuzer, Institutions and Innovation: Voters, Parties, and Interest Groups in the Consolidation of Democracy – France and Germany, 1870–1939 (Ann Arbor: University of Michigan Press, 2001), pp. 91–132.

²⁴ Peter Schindler, Datenhandbuch zur Geschichte des Deutschen Bundestages 1949 bis 1982, 3rd edn (Baden-Baden: Nomos, 1984), pp. 183–5.

²⁵ Noel Cary, The Path to Christian Democracy: German Catholics and the Party System from Windhorst to Adenauer (Cambridge, Mass.: Harvard University Press, 1996); Gerhard Loewenberg, ‘The Remaking of the German Party System’, in Mattei Dogan and Richard Rose, eds, European Politics: A Reader (Boston, Mass.: Little Brown and Co., 1971), pp. 259–80.

²⁶ Cary, The Path to Christian Democracy, 148.

²⁷ The European Union played a very similar, albeit much more indirect, role in East Central Europe. See Milada Anna Vachudova, Europe Undivided: Democracy, Leverage. and Integration after Communism (Oxford: Oxford University Press, 2005).

²⁸ Cox, Making Votes Count, p. 152.

²⁹ Daniel Rogers, Politics after Hitler: The Western Allies and the German Party System (New York: New York University Press, 1995), pp. 122–4.

³⁰ Schindler, Datenhandbuch; NetLexikon, ‘Deutsche Politik’, (http://www.lexikon-definition.de/Liste-der-Mitglieder-des-Deutschen-Bundestages).

³¹ Rogers, Politics after Hitler, p. 59.

³² Goldie Shabad and Kazimierz Slomczynski, ‘The Emergence of Career Politicians in Post-Communist Democracies: Poland and the Czech Republic’, Legislative Studies Quarterly, 17 (2002), 333–59; Bernhard Wessel, ‘Germany’, in Pippa Norris, ed., Passages to Power (Cambridge: Cambridge University Press, 1997), pp. 76–97; Jens Borchert and Lutz Golsch, ‘The Political Class in Advanced Democracies’, in Jens Borchert and Jürgen Zeiss, eds, The Political Class in Advanced Democracies (Oxford: Oxford University Press, 2003), pp. 142–63.

³³ Maurice Duverger, Les Partis politiques (Paris: Armand Colin, 1951), p. 292.

³⁴ Germany’s institutions – to the extent they affected strategic voting – were genuine causes rather than effects of prior non-institutional factors (i.e. party system, cleavages) determining their selection. This is an important issue because, if institutions were indeed pre-determined, then their effects would be spurious (Boix, ‘Setting the Rules of the Game’; Josep Colomer, ‘It’s Parties That Choose Electoral Systems (or, Duverger’s Laws Upside Down)’, Political Studies, 53 (2005), 1–21; Olga Shvetsova, ‘Endogenous Selection of Institutions and Their Exogenous Effects’, Constitutional Political Economy, 14 (2003), 191–212). The relevant discussion of endogeneity is to be found in Appendix 1.

³⁵ Chhibber and Kollman, The Formation of National Party Systems, pp. 263–92; Cox, Making Votes Count, pp. 186–90; Mainwaring, Rethinking Party Systems; Heather Stoll, ‘Electoral Coordination and Political Institutions: From Electoral Systems to the Power of the Prize’ (paper presented at the Annual Meeting of the American Political Science Association, Washington, 2005).

³⁶ In SMD, German voters defect in marginal numbers from smaller parties; such parties received only 2.8 per cent fewer first than second votes between 1953 and 1983 (Eckhard Esser, Wahlrecht zwischen Kontinuität und Reform (Düsseldorf: Droste Verlag, 1985), pp. 280–1).

³⁷ Arend Lijphart, Electoral Systems and Party Systems: A Study of Twenty-Seven Democracies, 1945–1990 (Oxford: Oxford University Press, 1994), p. 104.

³⁸ M. Tavits and T. Annus, ‘Learning to Make Votes Count: The Role of Democratic Experience’, Electoral Studies, 25 (2006), 72–90.

³⁹ Tavits and Annus, ‘Learning to Make Votes Count’, p. 77.

⁴⁰ Austin Ranney, ‘Candidate Selection and Party Cohesion in Britain and the United States’, in William Crotty, ed., Approaches to the Study of Party Organization (Boston, Mass.: Allyn and Bacon, 1968); Cox, Making Votes Count, pp. 157–60.

⁴¹ Johanna Kristin Birnir, ‘Stabilizing Party Systems and Excluding Segments of Society? The Effects of Formation Costs on New Party Foundation in Latin America’, Studies in Comparative lnternational Development, 39, no. 3 (2004), pp. 3–27, 4–14.

⁴² Williams Kieran, Brigid Fowler and Aleks Szczerbiak, ‘Explaining Lustration in Central Europe: a “Post-communist Politics”Approach’, Democratization, 12 (2005), 22–43; Pippa Norris, The Radical Right: Voters and Parties in the Electoral Market. (Cambridge: Cambridge University Press, 2005), pp. 83–95.

⁴³ At this point, the careful reader will have noticed that institutional factors show up in all three causal factors: historical factors (i.e. party licensing); co-ordination strategies (i.e. changing electoral threshold); and straightforward institutions (i.e. unchanged features of electoral system, federalism). This differentiation rests on the fact that institutions vary in their endogeneity, that is the degree to which they do or do not have independent causal effect. As historical factors, institutions are highly endogeneous because they either closely reflect the conditions that shaped them or, as is the case in post-war Germany, because they were temporally limited (i.e. party licensing was revoked in 1949). As co-ordination strategies, institutions still are endogeneous but slightly less so. Their effects no longer are limited by a sunset clause or all the conditions that originally shaped the institutions. Now, the endogeneity results only from those conditions that have changed since the adoption of the original institutions. Finally, as exogeneous institutional factors, institutions have a strong effect because institutions have become so far removed from the conditions originally shaping them that it makes more sense to ascribe an independent effect to institutions rather than arguing that they merely are reproducing some conditions prevalent long ago. They also have a strong effect if these effects are unintentional, that is, cannot be said to clearly reflect any systematic starting conditions. They still transmit antecedent conditions that shaped them but as these conditions were so random and unsystematic that the institutions cannot be said to transmit anything antecedent meaningfully (Adam Przeworski, ‘Institutions Matter?’ Government and Opposition, 39 (2004), 527–40, pp. 527–34.

⁴⁴ Lewis Edinger, ‘Post-Totalitarian Leadership: Elites in the German Federal Republic’, American Political Science Review, 54 (1960), 58–82, pp. 64–8.

⁴⁵ Stephen Padgett and Tony Burkett, Parties and Elections in West Germany: The Search for Stability (London: C. Hurst, 1986), p. 29.

⁴⁶ Heino Kaack, Geschichte und Struktur des deutschen Parteiensystems (Opladen: Westdeutscher Verlag, 1971), pp. 207–8.

⁴⁷ Heino Kaack, ‘Fraktions- und Parteiwechsler im Deutschen Bundestag’, Zeitschrift für Parlamentsfragen, 3 (1972), 3–27, pp. 20–1; NetLexikon, ‘Deutsche Politik’.

⁴⁸ Richard Stöss, ‘Der Gesamtdeutsche Block/BHE’, in Richard Stöss and Jürgen Bacia, eds, Parteien-Handbuch: Die Parteien der Bundesrepublik Deutschland, 1945–1980 (Opladen: Westdeutscher Verlag, 1984), pp. 1424–59; Jürgen Dittberner, ‘Die Freie Demokratische Partei’, in Stöss and Bacia, eds, Parteien Handbuch, pp. 1311–81.

⁴⁹ Eckhard Jesse, Wahlrecht zwischen Kontinuität und Reform:Eine Analyse der Wahlsystemdiskussion und der Wahlrechtsänderung in der Bundesrepublik Deutschland 1949–83 (Düsseldorf: Droste, 1985), pp. 226–7.

⁵⁰ Jesse, Wahlrecht zwischen Kontinuität und Reform, pp. 265–8. Kathleen Bawn, for example, claims, without clearly demonstrating how, that ticket splitting in the 1950s could have changed as many as seventeen seats (Kathleen Bawn, ‘The Logic of Institutional Preferences: German Electoral Law as a Social Choice Outcome’, American Journal of Political Science, 37 (1993), 965–89, p. 977.

⁵¹ Jesse, Wahlrecht zwischen Kontinuität und Reform, pp. 261–5.

⁵² Schindler, Datenhandbuch, pp. 106–10.

⁵³ Kaack, ‘Fraktions- und Parteiwechsler’, p. 21.

⁵⁴ Michael Laver and Kenneth Shepsle, ‘How Political Parties Emerged from the Primeval Slime: Party Cohesion, Party Discipline and the Formation of Governments’, in Shaun Bowler, David Farrell and Richard Katz, Party Discipline and Parliamentary Government (Columbus: Ohio State Universtiy, 1999), pp. 23–52; Aldrich, Why Parties? Barbara Geddes, Politician’s Dilemma: Building State Capacity in Latin America (Berkeley: University of California Press, 1994).

⁵⁵ Dittberner, ‘Die Freie Demokratische Partei’.

⁵⁶ Kaack, ‘Fraktions- und Parteiwechsler’, p. 19.

⁵⁷ These figures express the CDU’s net seat gains as result of switching and as such also take into account the seats it lost as a result of its deputies switching to minor parties.

⁵⁸ Switchers joining the CDU/CSU mattered somewhat more in 1953–57 because they increased the CDU/CSU’s parliamentary majority and thus lessened its dependence on the other parties making up the coalition government.

⁵⁹ Dittberner, ‘Die Freie Demokratische Partei’; Ute Schmidt, ‘Christlich Demokratische Union Deutschlands’, in Stöss and Bacia, eds, Parteien Handbuch, pp. 490–660; Alf Mintzel, ‘Die Christlich-Soziale Union in Bayers’, in Stöss and Bacia, eds, Parteien Handbuch, pp. 661–718; Cary, The Path to Christian Democracy, pp. 246–7.

⁶⁰ Cary, The Path to Christian Democracy, pp. 237, 266–7.

⁶¹ Cox, Making Votes Count, p. 67.

⁶² Cox, Making Votes Count, pp. 40–5, 61–2; Lijphart, Electoral Systems, pp. 134–8, 190.

⁶³ Cox, Making Votes Count, p. 68.

⁶⁴ Lijphart, Electoral Systems, p. 135.

⁶⁵ Schmidt, ‘Christlich Demokratische Union Deutschlands’; Dittberner, ‘Die Freie Demokratische Partei’.

⁶⁶ Schmidt, ‘Christlich Demokratische Union Deutschlands’.

⁶⁷ Hans Woller, ‘Wirtschaftliche Aufbau-Vereinigung’, in Stöss and Bacia, eds, Parteien Handbuch, p. 2460–81; Stöss, ‘Der Gesamtdeutsche Block/BHE’.

⁶⁸ U. W. Kitzinger, German Electoral Politics (Oxford: Clarendon Press, 1960), p. 38.

⁶⁹ Schindler, Datenhandbuch, pp. 106–10.

⁷⁰ It was exactly with this rescue objective in mind that the CDU/CSU fought for the inclusion of a secondary threshold in 1949 (see Jesse, Wahlrecht zwischen Kontinuität und Reform, pp. 250–70).

⁷¹ Kitzinger, German Electoral Politics, pp. 43–50.

⁷² Giovanni Capoccia, ‘The Political Consequences of Electoral Laws: The German System at Fifty’, West European Politics, 25 (2002), 171–202, p. 194.

⁷³ Kaack, Geschichte und Struktur des deutschen Parteiensystems, p. 220.

⁷⁴ Jon Elster, Claus Offe and Ulrich Klaus Preuss, Institutional Design in Post-Communist Societies: Rebuilding the Ship at Sea (Cambridge: Cambridge University Press, 1998); Tomas Kostelecky, Political Parties after Communism (Baltimore, Md.: Johns Hopkins University Press, 2002); Michael McFaul, ‘Explaining Party Formation and Nonformation in Russia: Actors, Institutions and Chance’, Comparative Political Studies, 34 (2001), 1159–87; Robert G. Moser, Unexpected Outcomes: Electoral Systems, Political Parties and Representation in Russia (Pittsburgh, Pa.: University of Pittsburgh Press, 2001); Hubert Tworzecki, Learning to Choose: Electoral Politics in East Central Europe (Stanford, Calif.: Stanford University Press, 2003).

⁷⁵ Theda Skocpol, States and Social Revolutions (Cambridge: Cambridge University Press, 1979); Ruth Berins and David Collier, Shaping the Political Arena (Princeton, N.J.: Princeton University Press, 1991); Gregory Luebbert, Liberalism, Fascism or Social Democracy (New York: Oxford University Press, 1991).

⁷⁶ For a valiant but, in my opinion, ultimately unsuccessful recent example, see Thomas Cusack, Torben Iversen and David Soskice, ‘Economic Interests and the Origins of Electoral Systems’, American Political Science Review, 101 (2007), 373–91.

⁷⁷ Mainwaring, Rethinking Party Systems, pp. 54–7.

⁷⁸ Giovanni Sartori, ‘Concept Misformation in Comparative Politics’, American Political Science Review, 64 (1970), 1033–53.

⁷⁹ Their importance is stressed by Katherine Stoner-Weiss, ‘The Limited Reach of Russia’s Party System: Underinstitutionalization in Dual Transition’, Politics and Society, 29 (2001), 385–414; Kitschelt et al., Post-Communist Party Systems.

⁸⁰ Andrew Abbott, ‘Transcending General Linear Reality’, Sociological Theory, 6 (1988), 169–86, pp. 171–2.

⁸¹ Colomer, ‘It’s Parties That Choose Electoral Systems (or, Duverger’s Laws Upside Down)’; Boix, ‘Setting the Rules of the Game’.

⁸² Shvetsova, ‘Endogenous Selection’; Marcus Kreuzer, ‘Germany: Partisan Engineering of Personalized Proportional Representation’, in Josep Colomer, ed., Handbook of Electoral Choice (Houndsmill, Hants.: Palgrave, 2004), pp. 222–36.

⁸³ Shu-Yun Ma, ‘Political Science at the Edge of Chaos? The Paradigmatic Implications of Historical Institutionalism’, International Political Science Review, 28 (2007), 57–78, pp. 64–8.

⁸⁴ Adam Przeworski and Fernando Limongi, ‘Modernization: Theories and Facts’, World Politics, 49 (1997), 155–83. For similar conclusions in the party literature, see Ingrid Van Biezen, ‘On the Theory and Practice of Party Formation and Adaptation in New Democracies’, European Journal of Political Research, 44 (2005), 147–74; Peter Mair, Party System Change: Approaches and Interpretations (Oxford: Clarendon Press, 1997), pp. 174–98.

⁸⁵ Dankwart Rustow, ‘Transitions to Democracy’, Comparative Politics, 2 (1970), 337–63.

⁸⁶ John Lewis Gaddis, The Landscape of History (Oxford: Oxford University Press, 2002), pp. 74–9.

⁸⁷ Colomer, ‘It’s Parties That Choose Electoral Systems (or, Duverger’s Laws Upside Down)’; Boix, ‘Setting the Rules of the Game’; Shvetsova, ‘Endogenous Selection’.

⁸⁸ Benoit, ‘Models of Electoral System Change’.

⁸⁹ Bawn, ‘The Logic of Institutional Preferences’, pp. 968–72.

⁹⁰ Erhard Lange, Wahlrecht und Innenpolitik (Meisenheim: Anton Hain, 1975), pp. 342–62.

⁹¹ Lange, Wahlrecht und Innenpolitik, pp. 376–88.

⁹² Lange, Wahlrecht und Innenpolitik, pp. 216–18, 255, 767.

⁹³ Heinrich Potthoff and Rudiger Wenzel, Handbuch Politischer Institutionen und Organisationen, 1945–1949 (Düsseldorf: Droste Verlag, 1983), pp. 333–42.