4th Circuit's Decision Striking the Discriminatory Law Stands as Valid Precedent...For Now
Today, the US Supreme Court denied cert in North Carolina's voting rights case, in which it was previously found that Republican lawmakers in the state were "targeting African American voters with...surgical precision."
The good news: this means that the 4th Circuit ruling in that case still stands, and the discriminatory legislation cannot be applied. Because this is a valid, standing federal court ruling, it can and will be cited by other courts hearing similar cases.
However, this may just be temporary. In denying cert, the Court cited the dispute between the NC Governor's office and the legislature in a battle over whether to withdraw the request for the Court to hear the case. In other words, this has nothing to do with the merits of the case, and it doesn't indicate anything about how the Court might rule in the next case to come its way.
You can find a good discussion of this on Rick Hasen's Election Law Blog.