From the Brennan Center, written before SCOTUS lit a match to judicial remedies for partisan redistricting, and even more relevant now.
Congressional redistricting is broken. In most states, districts are drawn by partisan lawmakers, and the manipulation of district boundaries for partisan or other discriminatory purposes is rife, with communities of color being amongst the hardest hit. While courts can provide a remedy, litigation is often slow and costly. This allows discriminatory maps to sometimes remain in place for years while court cases and the inevitable appeals run their course. But H.R. 1, the broad and historic democracy reform bill passed by the House in March, offers some smart, comprehensive ideas that would make the redistricting process fairer and more transparent.
This would of course require three things: Democratic control of the Presidency and both chambers of Congress, discarding the filibuster so Mitch McConnell can’t block it, and then hoping that SCOTUS doesn’t decide that, well, actually, Congress can’t do any of the things that HR1 enables. In that case, a little court-packing, or at least the sufficient threat of it, may do the trick. The first is within our power, the latter two may be as well. First things first, though.
I am not convinced that independent commissions draw better districts than legislatures, that setting forth a set of criteria does much to reign in map drawers, or that outlawing partisan gerrymander is an instant solution to redistricting problems. As an example, the City of Houston adopted a set of criteria which included compactness and maintaining communities of interest, and used those criteria as an excuse for the “functionally compact” District E which stretches from Kingwood to Clear Lake, skipping all the voters in between. If you abolish incumbency protection, then Congress Members Al Green, Sheila Jackson Lee, and Sylvia Garcia should all end up in the same district, since they live so close to each other.
Also worth pointing out that Harris County used their criteria throughout court trial to defend the inclusion of GOP-leaning precincts in Pct. 2.
The Brennan Center also discussed the effects of commissions on maps last year.
https://www.brennancenter.org/blog/redistricting-commissions-what-works
They are mixed results, but there are clearly good and bad practices that affect the process.
On a different topic, SCOTUS is unlikely to throw out HR 1 based upon the partisan gerrymandering part. Based upon Russo and the PA Supreme Court case, I think they are in the “I don’t want to hear it” mode. Throwing out HR 1 would require an active approach.