Explaining Divided U.S. Senate Delegations, 1788–1996: A Realignment Approach

We maintain that the rise and fall in the number of states with divided Senate delegations can be explained primarily in terms of long-run forces of realignment/dealignment and staggered Senate elections. We test our model with election data from 1788–1996 rather than only the post–World War II period, which was common in previous research. We show that a large number of divided Senate delegations is not new; indeed, the highest percentage occurred in 1830. Exactly as predicted by our model, we find a cyclical pattern in divided Senate delegations that is tied to realigning epochs. Our analysis also calls attention to the recent decline in the number of such delegations, and we argue that this trend may well continue.