Legislative Bipartisanship: Explaining Variation in Cross-Party Coalition Building Activity in the 99 State Legislative Chambers

Abstract

While an extensive literature is devoted to the antecedents and consequences of party polarization and gridlock, almost no attention has been devoted to the individual legislator level foundations of these aggregate level phenomena. Here I examine the factors that determine the extent to which individual legislators spend time forming cross-party rather than within-party coalitions — coalition building bipartisanship. It is such individual actions shaped by institutions, elections, and citizen and elite preferences that determine collective outcomes, including party polarization and gridlock. Using a national survey of over 3000 state legislators, I find the time a legislator devotes to cross-party versus same party coalition building is determined by political context, such as divided versus unified government, and by features of institutional design, namely supermajority requirements, and leadership professionalization — the former increases bipartisanship while the latter decreases it. A legislator's behavior is also strongly influenced by ideology — moderates engage in more cross-party coalition building than more extreme members. The effect of ideology is an individual, not chamber level, effect — the magnitude of the ideological divide between the parties is relatively insignificant in determining individual behavior. Partisan political context is also a key determinant of the time a legislator devotes to cross rather than within party coalition building. Of course, members of the minority in a chamber engage in the most bipartisan activity — a member of the minority cannot succeed legislatively without being part of a bipartisan coalition. Members of the majority in a divided government state are also motivated to spend more time on bipartisan coalition building. And each responds differently to the majority party's margin of control in the chamber — increasing the majority party's margin of control decreases the bipartisanship of majority members while it increases that of minority members.