Conditional Party Government and Member Turnout on Senate Recorded Votes, 1873-1935

According to the conditional party government thesis, party members bond or precommit themselves to supporting party positions under certain circumstances. A test of this thesis asks whether party members are more likely to participate in a roll call vote when the question has been identified by party leaders as important to the party. We show that party leadership signals systematically affected member turnout levels in the U. S. Senate during 1873-1935. On average, two-party turnout on party-salient votes rose by more than five members during 1873-1923 and more than three members during 1923-35 relative to "nonsalient" votes. These results also provide evidence of cohesive partisan behavior in the Senate well before the parties began the regular practice of designating floor leaders and whips.