Can governments elected under mixed-member majoritarian (mmm) electoral systems use geographically targeted spending to increase their chances of staying in office, and if so, how? Although twenty-eight countries use mmm electoral systems, scant research has addressed this question. The authors explain how mmm’s combination of electoral systems in two unlinked tiers creates a distinct strategic environment in which a large party and a small party can trade votes in one tier for votes in the other tier in a way that increases the number of seats won by both. They then explain how governing parties dependent on vote trading can use geographically targeted spending to cement it. These propositions are tested using original data from Japan (2003–2013) and Mexico (2012–2016). In both cases, municipalities in which the supporters of governing parties split their ballots as instructed were found to have received more money after elections. The findings have broad implications for research on mmm electoral systems, distributive politics, and the politics of Japan and Mexico.

Political parties are often faced with seemingly opposing goals when trying to secure members’ reelection and maintain party unity. On one hand, a party needs to fulfill members’ diverse electoral needs for their reelection, and on the other hand, the party must force members to vote in unison according to party lines for collective decisions. How does a party influence its members to take unified action while meeting their individual electoral needs? Through an analysis of the Japanese Diet, this study argues that parties attempt to achieve the reelection of their members and maintain party unity by manipulating legislative committee assignments and deliberations. In particular, the study demonstrates that a party shapes committees in a different way according to policy areas over which committees have jurisdiction. A party tends to accept its members’ requests for affiliation and allow their self-management in committees concerned with particularistic benefits so that they can deliver specific benefits to each electoral district. In addition, a party tends to assign members who have average policy positions in the party to committees concerned with general benefits to make policies that satisfy many constituencies.