Uncertainty and the Ideological Consistency of Roll-Call Voting in the U.S. Senate: The Case of Black Voter Enfranchisement in the U.S. South, 1961-2004.

Can ideological inconsistency in legislators' voting records be explained by the uncertainty they have about their constituents? Why does a two-dimensional model of roll-call voting explain the votes of some legislators better than others? We present an uncertainty-based theory of legislative search and ideologically inconsistent voting. We test this theory by examining whether U.S. senators' levels of uncertainty about their constituents leads to higher levels of inconsistent voting in Congress. Specifically we compare senators who faced large shifts in the racial makeup of their electorate due to enfranchisement with senators from more stable constituencies. We also examine other factors related to legislator uncertainty, such as legislators' backgrounds. We find that uncertainty due to black enfranchisement and uncertainty due to legislators' backgrounds both lead to higher ideological inconsistency among U.S. senators. Our results suggest that what some call "maverick" behavior by elected officials can be better characterized as best responses to a changing environment. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]