There's no question that the NC map is an egregious gerrymander. But past SCOTUS rulings would have considered them to be partisan gerrymanders, not racial gerrymanders. The WI case may well set the standard for partisan gerrymanders in court, and if so the NC gerrymander would probably fall under that standard. But this NC case is really testing a new theory about racial gerrymanders, not established law. If the Dems were seeking to overturn it on established law the case would have been decided at the beginning of the decade.
The legislative district boundaries were precleared by the USDOJ. Now the courts are saying that even though they could not have got preclearance without the 50%+1 districts, they shouldn't have done so.
The districts were also challenged in the state courts and upheld. That decision was appealed to US Supreme Court, which remanded the case to the NC Courts to reconsider their decision in light of the Alabama decision. The NC Supreme Court did so, and once again upheld the legislative district boundaries. The federal case was permitted to go forward only because there were independent sets of plaintiffs. I don't see how the SCOTUS can stay out of this considering that the NC courts were acting under their direct instructions.
So is it also your sense that this is a new theory about what constitutes racial gerrymandering?
Covington v North Carolina (PDF)What the court ruled was that everything had been subordinated to race. The chairs of the two redistricting committees had one person draw the maps (and only gave oral instructions). They told him to draw 50%+1 districts everywhere, which were referred to as VRA districts.
He also somewhat ignored the Whole County Provisions of the North Carolina Constitution as harmonized with OMOV and VRA by the NC Supreme Court. The North Carolina constitution forbids splitting of counties.
The NC Supreme Court has interpreted this to mean that counties should first be grouped based on the following rules:
(0) Draw VRA districts;
(1) Single-county, single member;
(2) Single-county, multi-member;
(3) Multi-county, multi-member, with groupings with fewer counties preferred.
There are some additional rules related to the division of multi-county, multi-member groups, such as minimize crossing of county boundaries.
In this case, because of the emphasis on drawing 50%+1 districts, in some parts of the state no multi-county groups were constructed. There was also a lot of precinct splitting, and general disregard for compactness measures (i.e. it was not even considered). So not only was consideration of race elevated, consideration of traditional redistricting criteria was depressed.
The court also found that there was no effort to demonstrate that the 3rd condition of the Gingles test was met (that white voters voting as a bloc denied the opportunity for the minority to elect their candidate of the choice.) (e.g a district that is 40% black, might elect the black candidate of choice if 17% of white voters crossed over)
North Carolina also offered as a defense that they were attempting to avoid retrogression. At the time the redistricting occurred, 40 counties in North Carolina were subject to preclearance. While not required now, it was at the time the redistricting was done, and is thus a legitimate consideration for using race in redistricting. In the baseline, North Carolina had nine 50% house districts and zero 50% senate districts. After the redistricting there were 27 50% house districts, and nine 50% senate districts.
What the Democrats want is a soft Gingles test: That wasting minority votes is an abridgement of the right to vote. This leads to titration of districts where the minimum number of blacks are placed in a district such that it will vote Democratic. Whites who vote Democratic are allies, whites who vote Republican are an oppressing bloc vote. The corollary is that the number of white Republicans who would be just as effective if they went fishing on election day is maximized.
The manipulation may actually alter voter behavior in terms of turnout.
Ideally, an electoral district is a neutral measurement device, that measures voter sentiment. But it can turn into an influence on voters in and of itself.