No vote dilution, as the state is a unit, and each vote within it is equally counted; this structure is baked into the Constitution, and reflected in the tiebreaking procedure in the House, where each state gets a single vote.
Freedom of Association right derives from the right to associate with the party of one's choice, not from the party's chances, or the expectation that the national party will pay much attention to you.
VRA S2 and Gingles challenge falls short, since there is not prospect of a minority majority district, the poll is for electors, not the ultimate candidates, and minority voters have equal opportunity to select candidates of their choice.