Doug Mataconis notes some very interesting graphs from Chris Cilliza in a post earlier this evening. The basic lesson of Cilliza’s graphs are quite correct: there has been a shift away from ideological overlap between the two parties, although the graphical representation in the presentation creates a false impression that the center has faded and that both parties have receded more to their respective ideological poles. However, that is a misrepresentation created by the way the graphs are drawn. Yes, the center, at least in terms of a legislative center, has eroded, but the erosion has not come about because House Democrats have gotten more liberal and House Republicans have become more conservative. Rather, the political science is pretty clear: the Democrats have not moved all that much, but Republicans have gotten substantially more conservative.
This has been well documented by political scientists at Voteview who have studied this issue for years. For example, there is this graph from their page on polarization, which I am pretty sure I have shared before, that shows the parties on a liberal-conservative dimension from 1879-2010:
While it can be seen that Democrats have gotten somewhat more liberal in recent year, Republicans have gotten substantially more conservative.
Using the same data, and updating for the most recent Congress, political scientist Thad Hall, writing at Mischiefs of Faction, extensively analyzes both the Gingrich Congress and the two most recent congresses and finds that the current Republicans are far more conservative than those in 1995. Indeed, he notes that the 1113th Congress (the current one) is substantially more conservative than the 112th.
Note the following:
In terms of Democrats and making the same comparison, the data shows the following:
when we look at the median member of the Democratic Caucus, there has been relatively little change in ideology. The median Democratic Caucus member in the 104th Congress would be very close to the Caucus median today. (By contrast, the median Republican from the 104thCongress would be a very liberal member of the Republican Caucus today.) As we move toward the “most liberal members” (from the 80th to 100th percentile) of the Democratic Caucus, there has been almost no change in ideological placement over this time.
So, setting aside anything else for the moment, the empirical analysis demonstrates that in just under twenty years the Republicans in the House have shifted substantially rightward. Further, the that shift has been more rapid of late.
Voteview also has a post on this comparison: The Shutdown: Boehner vs. Gingrich.
The changes in legislative behavior, whether one likes them or not, are not the result of both parties becoming more ideological. Rather, the shift is on the GOP side of things. This is not a startling revelation, to be sure, to observers of American politics, but this is not an impressionistic exercise laid out above, but rather one of using a consistent empirical measure over time and recording the changes. In other words, it just doesn’t seem like the GOP is more conservative, by the measure of above, they clearly are more conservative. So, to deploy (and negate) a common cliche: both sides aren’t doing it.
This situation also, therefore, explains why many feel as if the Republican Party has changed, because it has.
(This is a quick and cursory treatment of a complicated issue–I very much recommend reading the posts linked and exploring the Voteview site).
