Alan Abramowitz on politicians and ideological conformity

In response to my note on the limited ideological constraints faced by legislators running for reelection, Alan Abramowitz writes:

I [Abramowitz] agree–although they probably have less leeway now than in the past due to growing pressure toward ideological conformity within parties, especially GOP. But one thing that struck me as very interesting in your graph is that it looks like the advantage of a moderate voting record is considerably smaller now than it used to be, down from over 4 percentage points in the 1980s to maybe 1.5 points on average now. It suggests to me that the electorate has become increasingly partisan and that fewer voters are going to defect to an incumbent from the opposing party regardless of voting record. This could reflect more concern among voters with party control of Congress itself. Along these lines, one thing I’ve found in the NES data is a growing correlation between presidential job evaluations and voting for both House and Senate candidates over time.

My reply: Yes, that makes sense. The trend is suggestive although (as you can see from the error bars) not statistically significant. Recently I have not had my thoughts organized enough to write any articles on this stuff, but it feels good to at least post these fragments for others to chew on.