When Loyalty Is Tested: Do Party Leaders Use Committee Assignments as Rewards?

Theories of parties in Congress contend that one tool that party leaders possess to induce loyalty among rank-and-file members is control over committee assignments, but conventional tests of this linkage have failed to distinguish loyalty from simply voting one's preferences in accordance with party leaders. We characterize loyal legislators as having a higher propensity for voting with party leaders when it matters, even when their preferences diverge from the mainstream of their party. Testing this strong definition of loyalty on committee assignment data for 1991-2015, we show that majority party members who support their party on the subset of votes for which party leaders have taken positions in floor speeches are more likely to be rewarded with plum committee assignments, especially those members on the ideological extremes.