How has the federal electoral college system been interpreted in federal and state law?

26 Gray v. Sanders (1963) 372 U.S. 368, 83 S.Ct. 801, 9 L.Ed.2d 821, held that Georgia's 'county unit system' (somewhat analogous in operation to the federal electoral college) unconstitutionally diluted the weight of some votes on the basis of geographical location. Gray stands for the proposition that 'Once the geographical unit for which a representative is to be chosen is designated, all who participate in the election are to have an equal vote * * *.' (372 U.S. at p. 379, 83 S.Ct. at p. 808.)