Connecting the Dots Between Partisanship and Gridlock
The Brookings Institution’s Vital Statistics on Congress provides average party ideology scores going back to 1947, based on voteview’s DW-NOMINATE numbers. Combining these figures with bill passage numbers from the Resume of Congressional Activity, we get a pretty clear picture of the link between increasing polarization (measured here as the gap between the average ideology score of each party) and decreasing legislative activity.
Some standouts in the data: in the Senate, there’s a period of relative stability in the 70s and 80s, visible as a tangled cluster of values. Looking along the x-axis, it’s plain that in the 2013-2014 term the ideological gap widened considerably. In the house, a similar jump occurred between ‘94 and ‘96 - the time of the Gingrich Revolution.
As this chart from Brookings makes clear, the widening gulf between the parties is primarily due to a strong rightward shift in the GOP. While the gap between parties can theoretically widen indefinitely, we are nearly at the rock-bottom of legislative activity - the Senate, for instance, only passed 14 bills last year. Whether we’re at the bottom of a trough or the start of a new normal remains to be seen.
Notes on data and charts: The “projected” values for the term ending this year use the actual DW-NOMINATE scores listed on voteview.com, combined with a projected number of bills passed based on A)the number of bills passed in the 2013 session and B) the average increase from first to second session throughout the 2000s. The inspiration for the connected scatterplots is Hannah Fairfield’s work at the New York Times, as seen in a blog post by Alberto Cairo.