The death of Sen. Dianne Feinstein (D-Calif.) last night changes the makeup of the U.S. Senate, reducing the number of Democrats (and Independents who caucus with or are “formally aligned” with Democrats) in the chamber to 50. As political scientist Christian Grose pointed out, the last time a senator died sending the Senate this narrow a majority, and effectively a tie was 1953-54.
Grose studied that Senate closely in an article authored with Nicolas Napolio, was published in the American Political Science Review. After Sen. Dwight Griswold (R-Neb.) died unexpectedly of a heart attack in 1954, the Senate majority and thus control shifted (for just one month) from the Republican to the Democratic party. Napolio and Grose’s research showed that the change in majority party control caused “changes both to the agenda and to legislators’ revealed preferences.”
Here’s the study’s abstract:
Does majority party control cause changes in legislative policy making? We argue that majority party floor control affects legislator behavior and agenda control. Leveraging a natural experiment where nearly one tenth of a legislature’s members died within the same legislative session, we are able to identify the effect of majority party floor control on the legislative agenda and on legislator choices. Previous correlational work has found mixed evidence of party effects, especially in the mid-twentieth century. In contrast, we find that majority party control leads to (1) changes in the agenda and (2) changes in legislators’ revealed preferences. These effects are driven by changes in numerical party majorities on the legislative floor. The effects are strongest with Republican and nonsouthern Democratic legislators. The effects are also more pronounced on the first (economic) than the second (racial) dimension. Additional correlational evidence across 74 years adds external validity to our exogenous evidence.