Aside from the Dems never doing this, and the threat that they would make threatening noises in CA and NY not creditable, SCOTUS has a case before it, and while I doubt their ruling will be as dire as some suggest, I think it would be hostile to a national law dictating how to redistrict.
The killer however is what would be in such legislation? What is the fix? The Muon2 rules, something vague that is subject to abuse (CA for example is not doing very well, we had the Mathismader in AZ, MI did not do a very good job, and agree or disagree, there is a lot of subjective discretion going on.
As to policy, I stand by the VA approach.
The SCOTUS point is def fair and yeah, this is never going to happen just because of the partisan nature of DC and this issue specifically.
You also birng up the point of subjectivity. The Muon2 rules may work in some cases, but in western states where you have these "supercounties" that don't really align with clear community or even geographic, boundaries, you are going to get some really cursed districts.
Of the commissions, I thought the worst was probably Cali this cycle just because of how much emphasis they put on creating "minority access" seats above everything else. Stuff such as splitting San Jose like 4 ways to racially sort it or CA-41 being a leftover district of sorts is insane.
I actually felt like the Michigan Commission did pretty good with the congressional maps, but they def flopped at the state legislative level. Firstly, at the state legislative level, you had their VRA lawyers arguing that they should unpack the Detroit seats to make them only like 40% black to extend black influence which no only looks egregious but backfired. Secondly, it's clear they made a pretty robust effort to "unpack" Dem voters from places like Ann Arbor and Lansing to meet the partisan fairness requirement.
In VA, the commission outright failed, but the court map with the bipartisan special masters turned out to be really good and honestly, it's hard to complain. The map in my subjective view does a good job at balancing compactness, overall partisan fairness, COIs, and giving voters of color a voice, but again those values are subjective and people's views on which are the most and least important will differ greatly.
In CO, AZ, and WA, the commissions still had partisan undertones even if they were bipartisan, which I don't think was great. WA did a least change incumbent protection map to a map that was already messy and had clear issues. In CO, you had that one commissioner who kept saying that the map had to be 4-1-3 above all else to be fair which wasn't great, though overall I think the map is ok. In AZ, the racial sorting and the part of a single tiebreaker isn't exactly great. Last cycle it led to a slightly D favorable map to now a slightly R favorable map.
In PA and NC, the court maps have very clear issues. In NC, the court directly drawing the map themselves in such a short period of time is the equivalent to letting any random educated person draw a map. In PA, the court was choosing between a bunch of frankly bad options, all of which had partisan undertones one way or another. The map they chose was sort of the least offensive because it changed the least from the old map which was drawn by a special master.
In NY, Cervas did quite a decent job imo. On the congressional level, he greatly cleaned things up where needed, but still used the old map as his ultimate guide.
If it were up to me, I might actually go with a system similar to MI but with a few extra safeguards, more time, and no partisan fairness requirement. MI uses citizens and at first some of their maps were pretty crazy, but they ultimately landed on a congressional map that is one of the best in the nation imo. I also liked how they had folks from all around the state who brought genuine insight from the communities they live in; I think this was especially important in terms of how they broke up the Detroit metro. Having one set of commissioners for each map that needs to be drawn would probably be the way to go, because tbh the legislative maps seemed like a bit of afterthoughts because they weren't really able to go through district by district and were so worried about meeting partisan fairness at the expense of a good map.
While the VA map is good, I think it puts too much power in the hands of the courts for a task they aren't really intended to do, and other pairings of speical masters may not work out as well.
