Scott Winship has an insightful post on the sources of political polarization in recent years, drawing on Jacob Hacker and Paul Pierson’s influential Off Center. Hacker and Pierson argued that while Republicans had moved sharply to the right, the electorate as a whole did not. Moreover, the Democrats failed to move to the left to counter the Republican’s rightward shift, and so the entire political spectrum was forced to the right, alienating the moderate electorate.
Since the rightward shift of Republicans occurred during a period in which Hacker and Pierson showed the distribution of self-identified ideology had not changed, the implication was that the electorate was being deprived of the more progressive policies that it desired. But a closer look at their data and analyses shows that while the increase in polarization among legislators has occurred disproportionately among Republicans, the evidence hints that this is because it proceeded from a Nixon-era Democratic Congress that was well to the left of the electorate.
Rather than refuting the idea that policy reflects the preferences of voters in the middle (the “median voter theorem”), as Hacker and Pierson claimed, the evidence actually bolsters this view. Correcting their claims is important if progressives are to govern effectively. Republicans did not simply pull public policy to the right of where Americans preferred, and now that Democrats are back in control of Congress, progressives should not assume that the median voter is leftier than she really is.
The rest of Winship’s post is a careful analysis of the data presented by Hacker and Pierson, and it’s well worth your time.