"Little Evidence to Support Gerrymandering-Polarization Link"
Brendan Nyhan has an informative post up building on my contention yesterday that we shouldn’t overstate the role of gerrymandering in producing polarized legislative politics. He offers up this abstract of a new paper from Princeton’s Nolan McCarty, UCSD’s Keith Poole, and NYU’s Howard Rosenthal (a great team, incidentally, for bringing the political science to punditry-relevant topics):
Both pundits and scholars have blamed increasing levels of partisan conflict and polarization in Congress on the effects of partisan gerrymandering. We assess whether there is a strong causal relationship between congressional districting and polarization. We find very little evidence for such a link. First, we show that congressional polarization is primarily a function of the differences in how Democrats and Republicans represent the same districts rather than a function of which districts each party represents or the distribution of constituency preferences. Second, we conduct simulations to gauge the level of polarization under various “neutral” districting procedures. We find that the actual levels of polarization are not much higher than those produced by the simulations. We do find that gerrymandering has increased the Republican seat share in the House; however, this increase is not an important source of polarization.
If you want to think about this in anecdotal terms, consider former congressman Chris Shays (R-CT), famous for several cycles for being the Republican with the most-Democratic district in the House. Given that progressive constituency Shays was, as you can imagine, a pretty moderate Republican. But nevertheless, the most serious analysis out there consistent found Shays position to the right of every single member of the House Democratic caucus, even though many Democrats represented more GOP-friendly seats than Shays’. And when you think about it, this is really what congressional polarization consists of. The fact that the congressmen with very conservative districts have very different views from those with very liberal districts is pretty uninteresting.
What makes congress polarized is when even the most-liberal Republican is more conservative than the most-conservative Democrat. And you can’t blame that on polarization. Representative Cao, for example, didn’t vote against the stimulus bill because his seat’s too safe. Neither did Mike Castle who holds the Delaware at-large seat. I don’t know what did make those guys vote no, but it definitely wasn’t gerrymandering. But the way we know the House is very polarized is that even those guys voted against the bill.
Serious gerrymandering seems like a bad idea anyway, but for a lot of people in DC the idea of changing the redistricting process has become a kind of weird idée fixe that prevents them from seeing what’s going on.