"If you think Congress would never enact a statute to require that congressional districts be compact; keep towns, counties, and cities together; and not take partisanship into account, ask yourself which is more likely: that Congress would do this or that it would change the entire system of electing members of Congress through proportional representation, with all the other changes that would have to accompany that (would voters vote for a party list, rather than individual members? would party leaders have the power to choose those lists? etc).
"One issue is that I don't what the likely partisan outcomes overall would be if this approach were adopted nationally. This would be a process-based, rather than outcome-based, approach to redistricting -- a tension I've written about before. If this approach would tend to generate overall partisan outcomes that would significantly favor one party or the other, there's probably little likelihood Congress would enact it. But if not, this approach is worth considering."