Principal agent theory implies that legislators will delegate power to a leader only when they need the leader's help and the leader can be expected to provide satisfactory help if granted power. This study is the first to evaluate the implied interaction between legislators' need for help and the degree to which legislators and leaders have similar preferences. By analyzing the Speaker's powers in the U.S. states, I arrived at three key conclusions. First, institutional leadership power responds to the interaction between preference alignment and policymaking challenges. Traditionally expected effects only appear when both alignment and challenges are relatively high. Second, professionalization causes weaker leadership powers. Finally, electoral competition correlates with stronger appointment, committee, and resource powers, but weaker procedural powers.

I dentifying policy status quo locations is a precondition for testing key predictions of many spatial models of legislative politics, but such measures have proved to be extremely difficult to construct. This study applies a novel technique that measures policy locations in relation to legislators' preferences. The resulting status quo estimates allow for a direct test of the policy consequences predicted by pivotal politics and party cartel theories of legislative politics. The empirical tests indicate that parties interact with pivotal politics to contribute to policy gridlock and shape policy change. By bringing pressure to bear on pivotal politics "pivots" and by blocking policy changes that would "roll" the party, parties increase the range of policies subject to gridlock in the American political system.

We present a new unified dataset of common-space ideal points, committee assignments, and financial interests for all state legislators in 1999. We describe the compilation of the dataset and offer a few possible applications.