From the Wikipedia article “Redistricting Commision”: 

Legislatures control redistricting in states marked yellow, while commissions control redistricting in states marked green. In states marked purple, non-partisan staff proposes the maps, but the state legislature votes on the proposal. States marked grey have only one representative.

Since at least August 19, 2012, in my post “Persuasion,” I have been an enthusiastic proponent of nonpartisan. There I wrote:

Many people may not realize the extent to which political polarization in the House of Representatives arises from partisan and pro-incumbent redistricting. When electoral districts are designed to be either safe Republican or safe Democratic districts, then the main fear for a politician seeking reelection is losing in the primary. That typically pulls members of the House of Representatives toward the extremes. Nonpartisan redistricting is a way to have more districts be competitive in the general election and so make those running for Congress worry more about the general election relative to how much they worry about the primary. I believe this would pull politicians toward to center and toward a greater willingness to work with those in the other party. Getting change to happen in this area will be hard, but there are groups already working on this. I believe the long-run value to our Republic of nonpartisan redistricting would be substantial.

In other words since most (all but about 40 of 435) Congressional districts are designed to be safe for one party or the other, those in Congress often take actions to please their bases rather than the center. That in turn tends to push Congress toward being more of an arena of posturing rather and less of an arena for deliberating about helpful legislation.  

So I am pleased that the Supreme Court upheld the constitutionality of redistricting commissions. (I am not sure the text of the Constitution fully supports this decision, so ideally it would be good to have a constitutional amendment declaring them legal–and going beyond that, requiring them for all states.)

I hope with the issue of constitutionality settled that more and more states adopt redistricting commissions. Though this may involve short-run sacrifices of reelection probabilities, I think this is actually even in the long-run interest of a party in control of a given state, since parties that get used to appealing to the center to a greater degree are likely to grow in influence.