Valence Advantages and Ideological Shirking in the U.S. Senate: Why Do Senators Take Positions That Are Different From Their Constituents' Preferences?

Do non-policy valence advantages that incumbent members of Congress possess affect spatial position-taking? Are legislators who deliver substantial amounts of federal largesse more likely to diverge from their constituency medians? Are legislators who are perceived as more competent than their opponents more likely to diverge from the preferences of their constituents? I argue and empirically demonstrate that valence advantages such as the distribution of "pork" projects and legislator competence allow incumbent legislators to deviate from the policy preferences of their constituents (in some instances). Formal valence theories of position-taking are examined in this paper, and I argue for an expansive definition of valence advantages that includes both valence policies and non-policy valence characteristics. I show that valence advantages sometimes cause legislators to converge to their constituents' preferences and to sometimes diverge. I test the expectations of valence theories of congressional position-taking by examining an example of a valence issue (distributive policy) and a valence characteristic (an incumbent's perceived competence relative to his or her challenger). These empirical tests are conducted with original data on senators' divergence from their states' median voters during the 104th-107th Congresses (1995-2002). One key contribution of this paper is the creation of ideal point estimates of legislators and constituency medians on a common scale using Bayesian MCMC ideal point estimation techniques (similar to the popular NOMINATE scores, though unlike NOMINATE, these scores include measures of constituents and senators). The findings are that valence theories of position-taking are demonstrated when examining incumbent divergence from the constituency median. In sum, senators with no valence advantage diverge from their constituents; senators with small valence advantages move closer to their constituents; and senators with large valence advantages are able to deviate far off of their constituents' preferences. The implications of these results are that senators who deliver very large amounts of federal outlays to a state or senators perceived as very competent relative to their campaign challengers are able to vote closer to their own personal preferences than to their constituents' preferences. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]