At the Election Law Blog, Rick Pildes describes two rationales for adopting proportional representation (PR) nationally. One of these is anti-gerrymandering. He describes the other as the effort to induce a system of 5-6 political parties. On both, he writes:

There’s another issue to flag about the relationship between these two versions of PR in the rhetoric around reform. I’m concerned that advocates for the second version of PR will draw on the intuitions behind the first version of PR to gain support for the second version. In other words, support for the first version of PR will become a Trojan Horse for the second version.

Two points are worth making:

1. The U.S. House of Representatives already is expected to produce effectively 2.8 legislative parties and 4.6 electoral parties. Where are they?
2. What if the second rationale were precluding serious consideration of the first?

I otherwise agree with Prof. Pildes’ analysis of PR adoption prospects:

But there’s also the political economy mountain that seems especially insurmountable with this version. I think most reformers envision unified Democratic control of Congress and the White House as required for any change of this sort. But is the Democratic Party, having managed to attain that level of control, likely to agree to fragment itself into three different parties, along with however many parties the Republicans would fragment into?

For these and other reasons, I recommend minority-party representation (MPR) as an anti-gerrymandering device.