The Gingrich Senators and Party Polarization in the US Senate

The political parties in the Senate are almost as polarized at they are in the House. Nevertheless, the explanations for party polarization work better in the House than they do in the Senate. In this article, we argue that the polarization in the House has directly contributed to polarization in the Senate. We find that almost the entire growth in Senate party polarization since the early 1970s can be accounted for by Republican senators who previously served in the House after 1978-a group we call the "Gingrich Senators." While our analysis indicates that part of this effect has its roots in the senators' constituencies, the experience of these representatives serving in the House continues to exert a real and substantial effect on their voting behavior in the Senate.