The federal courts' essentially incoherent jurisprudence on racial gerrymandering and the creation of majority-minority districts became even more so with today's Supreme Court ruling invalidating two of North Carolina's congressional districts.
All nine justices agreed that one of the two seats in question — North Carolina's 1st Congressional District — was created based on impermissible racial criteria. The reason that even the dissenting justices concurred in this part of the decision is that state legislative leaders made the mistake of openly saying they were deliberately creating this district as a 51 percent black-majority district in order to get preclearance from the Obama administration's Justice Department.
So this is the point of greatest agreement: All nine justices were on the same page that the easiest way to violate Section Two of the Voting Rights Act is to try very hard to follow it. (The 1st District, by the way, is not especially weird-shaped, drawn almost entirely along county lines.)
You can forgive Republican state legislators' frustrations at having their maps stricken again and again based on what ultimately amounts to their determination not to draw a map that maximizes Democratic victory potential. Because this is how it really works: When Democrats lose, they sue either because black voters are being distributed between districts, or because they are packed into too few districts, whichever applies. If there aren't enough black voters in the area in question to make that case, they come up with some novel theory, as they tried unsuccessfully in Pennsylvania in 2004 and are currently trying in Wisconsin.
The bone of contention that created a 5-3 split on the court was the 12th Congressional District, an infamous seat that was previously shaped like a snake running from southwest to northeast in the center of the state. That district came before the court again and again over the years (this is its fifth appearance before the Supreme Court). Justice Clarence Thomas sided with the liberal majority in ruling that its composition had been impermissibly determined by racial considerations. (Justice Gorsuch had not been confirmed when the case was argued, and he took no part in the ruling.)
This is a very complicated subject, but at first read I'd point to what Justice Samuel Alito said in his dissenting opinion about litigation like this case, in which he was joined by Justice Anthony Kennedy and John Roberts. Although he doesn't mention a political party, he basically summarized how Democrats are currently trying, in many district and circuit courts in cases where race isn't even a factor, to undo the democratic process through lawsuits over redistricting in order to make up for the fact that they lost so many elections during the Obama era.
Here is what Alito wrote, warning that "federal courts will be transformed into weapons of political warfare":
Unless courts "exercise extraordinary caution" in distinguishing race-based redistricting from politics-based redistricting, they will invite the losers in the redistricting process to seek to obtain in court what they could not achieve in the political arena. If the majority party draws districts to favor itself, the minority party can deny the majority its political victory by prevailing on a racial gerrymandering claim. Even if the minority party loses in court, it can exact a heavy price by using the judicial process to engage in political trench warfare for years on end.
Although I do not imply that this is what occurred here, this case does reflect what litigation of this sort can look like. This is the fifth time that North Carolina's 12th Congressional District has come before this Court since 1993, and we have almost reached a new redistricting cycle without any certainty as to the constitutionality of North Carolina's current redistricting map.