bq. I thought I might add that not only do I not believe that gerrymandering is responsible for political polarization, I don’t even think gerrymandering has played a large role in making House seats uncompetitive
That’s Matt Yglesias. He’s correct. Here’s the abstract of a relevant new paper by John Friedman and Richard Holden:
bq. The probability that an incumbent in the U.S. House of Representatives is reelected has risen dramatically over the last half-century; it now stands at nearly 95%. A number of authors and commentators claim that this rise is due to an increase in bipartisan gerrymandering in favor of incumbents. Using a regression discontinuity approach, we find evidence of the opposite effect. All else equal, changes in redistricting have _reduced the probability of incumbent reelection_ over time. The timing of this effect is consistent with the hypothesis that legal constraints on gerrymandering, such as the Voting Rights Act, have become tighter over time. Incumbent gerrymandering may well be a contributor to incumbent reelection rates, but it is less so than in the past.
Emphasis mine. Here are gated and ungated versions of the paper.