Core argument
Explaining the growth of Democratic leadership power in the U.S. House after the 1970s reforms, Rohde (1991) argued that strong parties require two conditions: preference homogeneity within parties and preference divergence between them. When both hold, members trust leaders to represent their views and delegate more power.
The context of party theories
Aldrich (1995) broadened the background by explaining that parties form to solve collective-action and electoral-coordination problems. Cox and McCubbins (1993, 2005) proposed the party cartel theory, in which the majority controls committee and floor agendas to block unwanted bills; together with conditional party government, it forms the core of party-centered theories of Congress. Growing distance between parties through partisan sorting is read as strengthening the theory's conditions.
Critiques and tests
Krehbiel (1993) questioned whether parties have independent influence, arguing that apparent party effects reflect individual members' preferences. Snyder and Groseclose (2000) and Cox and Poole (2002) separated preferences from party pressure in roll-call data and found independent party effects. Lee (2009) reported partisan conflict even on issues without ideological differences.
FAQ
- What is conditional party government in simple terms?
- When members of a party think alike and differ sharply from the other party, they give their leaders more power.
- Why is it called conditional?
- Because leadership power is not always strong; it grows only when intraparty cohesion and interparty differences are present.
Sources reviewed: 2026-10-26
References
- Rohde, D. W. (1991). Parties and leaders in the postreform House. University of Chicago Press. The book that introduced conditional party government.
- Aldrich, J. H. (1995). Why parties? The origin and transformation of political parties in America. University of Chicago Press. Rational-choice account of why parties exist.
- Cox, G. W., & McCubbins, M. D. (1993). Legislative leviathan: Party government in the House. University of California Press. The cartel theory, a companion account.
- Cox, G. W., & McCubbins, M. D. (2005). Setting the agenda: Responsible party government in the U.S. House of Representatives. Cambridge University Press. Majority-party agenda control.
- Krehbiel, K. (1993). Where's the party? British Journal of Political Science, 23(2), 235–266. The main skeptical critique.
- Snyder, J. M., Jr., & Groseclose, T. (2000). Estimating party influence in congressional roll-call voting. American Journal of Political Science, 44(2), 193–211. Estimates party pressure in roll calls.
- Cox, G. W., & Poole, K. T. (2002). On measuring partisanship in roll-call voting: The U.S. House of Representatives, 1877–1999. American Journal of Political Science, 46(3), 477–489. Long-run measurement of partisanship.
- Lee, F. E. (2009). Beyond ideology: Politics, principles, and partisanship in the U.S. Senate. University of Chicago Press. Partisan conflict beyond ideology.