1 Does party polarization lead to bad legislation? If so, why not? Keith Krehbiel * Although it is well-studied, the topic of party polarization and its consequences still elicits enough head-scratching that it may be wise to take a fresh look at a seemingly well-established proposition. In this essay, I attempt to show that the usual answer to the first titular question deserves reconsideration, that its reconsideration gives rise to the paradoxical second question, and that the resolution of the paradox supports a more sanguine view of partisanship and its legislative consequences. Does party polarization lead to bad legislation? In a word, yes. The consensus view of political scientists and pundits is that bad legislation is common and that party polarization is to blame. 1 This view is grounded in mainstream beliefs about how the contemporary Congress works—or, in this instance, doesn’t. According to Sinclair (2007), for example, party polarization in Congress is a condition ripe for procedural empowerment of the House’s or Senate’s majority party. The majority party’s size, organizational, and procedural advantages give rise to bold partisan initiatives (which the minority prefers to call radical proposals). The ability of the majority party to craft extreme proposals, exercise procedural control, enforce discipline, and squelch dissent within its ranks are, in various combinations, sufficient for legislative success, where success is measured by the degree to which legislation comports with what the median member of the majority party wants. With less evidence * Edward B. Rust Professor of Political Science, Graduate School of Business, Stanford University, Stanford, CA, 94305. I appreciate helpful communications with Larry Evans, Mo Fiorina, Mattias Polborn, Eric Schickler, Alan Wiseman, and Jack Wright. (Version 4.2.2007.) 1 By bad legislation I mean (loosely) legislation that is more extreme than what most people want, or (precisely) legislation that comports with preferences of an extreme and homogeneous majority party. Party polarization has two components: a large distance between Democrats’ and Republicans’ policy stances, and large agreement within each party about its stances. These conditions are often called (inter- party) distance and (intra-party) homogeneity.