What explains party unity? A test of competing theories

Several theories have been created to explain party unity in Congress, but previous studies have generally assumed the same factors affect party unity for both parties. Given the differences between the two parties (the ideological heterogeneity of their electoral coalitions, how the party’s electoral coalitions view partisanship, etc.), this assumption may limit our understanding of the sources of party unity. In this paper, I test three theories of party unity (cartel theory, Conditional Party Government, and Strategic Party Government) on separate panels for the two parties. I find cartel theory helps explain party unity for both parties, but, unlike what has previously been argued, I find this is not entirely due to Reed’s Rules. I further find Conditional Party Government better explains party unity for the Republicans, while Strategic Party Government better explains party unity for the Democrats. I provide theoretical reasons for these findings and how they may impact future research.

Pre-electoral coalitions and cabinet stability in presidential systems

Previous research on coalition stability in presidential systems has relied to a substantial extent on the parliamentary literature. By focusing on the post-electoral bargaining environment, these approaches have neglected the key role played by pre-electoral agreements formed around the winning presidential candidate in the making and breaking of coalitions under presidentialism. We claim that cabinets derived from pre-electoral coalition should foster trust and reduce uncertainty regarding partners’ future behaviour. However, the positive effect of pre-electoral coalitions over cabinet duration is conditional on cabinet status, that is, the control of a legislative majority or near majority. Therefore, we argue that pre-electoral coalition cabinets holding a majority or near majority of seats will be more durable than purely post-electoral majority coalitions, whereas minority pre-electoral coalition cabinets congruent should endure less than minority post-electoral coalition cabinets. We test these hypotheses using a dataset of pre- and post-electoral coalitions in 11 Latin American countries.

Italy: Continuous Change and Continuity in Change

Few democracies in the world have experienced so many transformations in the electoral and party systems as has Italy since the early 1990s. Therefore the study of the Italian case is an excellent opportunity to investigate if and how these changes impact on the government’s role in the decision-making process, on government formation and termination, and on the governance stage. Although the formal rules concerning executive–legislative relations have remained almost unaltered, since the 1990s Italian governments have increased de facto their agenda-setting power. Since 1994, the party competition dynamics and the electoral rules induced the political parties to build electoral alliances and pre-electoral coalitions. However, the persisting high level of internal fragmentation made Italian governments also very unstable compared to the governments in many other European democracies. The instruments of intra-coalitional conflict resolution used in Italy have been for long time quite informal and mostly based upon decision-making bodies partially external to the executive. The above cited changes at the beginning of the 1990s, by increasing the overlapping between government leadership and party leadership, made these mechanisms more internal to the government arena. Recent political and institutional developments—especially after the 2013 and 2018 general elections and the new electoral rules—leave very open and uncertain the prospects of consolidation of all these changes.

The Era of Coalition Government in Japan: The Institutional Logic of Surplus Majorities and Strange Bedfellows

For nearly four decades after its establishment in 1955, Japan’s Liberal Democratic Party formed every government alone. Since mid-1993, however, coalition government has been the norm in Japanese politics. Interestingly, every coalition since 1999 has included a party with a lower house majority by itself. Nonetheless, these majority parties have taken on coalition partners. This chapter shows that the logic of “oversized” coalition government in Japan is driven in part by parliamentary bicameralism, and partly by the mixed-member electoral system, which incentivizes the formation of long-lived pre-electoral coalitions.