Courts have stepped in on voting issues before - and they will again...
https://en.wikipedia.org/wiki/Baker_v._Carr
“Baker v. Carr and subsequent cases fundamentally changed the nature of political representation in America, requiring not just Tennessee but nearly every state to redistrict during the 1960s, often several times. This re-apportionment increased the political power of urban areas with greater population and reduced the influence of more rural areas.[6] After he left the Court, Chief Justice Earl Warren called the Baker v. Carr line of cases the most important in his tenure as Chief Justice.[7]”
And PRIMARIES are private affairs.