William O. Douglas

“ We cannot regard it as any the less the constitutional purpose, or its words as any the less guarantying the integrity of that choice, when a state, exercising its privilege in the absence of Congressional action, changes the mode of choice from a single step, a general election, to two, of which the first is the choice at a primary of those candidates from whom, as a second step, the representative in Congress is to be chosen at the election. ”

“ We deal here not with the primary election for either members of Congress or the Senate but with the nominating process for a primary election [1] in which convention delegates favorable to a particular presidential candidate are chosen, the convention choice ultimately to compete for President in an election under Article II of the Constitution—a procedure that Congress has regulated in detail. ”

“ A voter recently moving to a new district and registering in time nevertheless loses his franchise—not because of any disqualification or irregularity, not because of his failure to do something required, and not because of his commission of a wrongful act. He has done all in his power to qualify as a voter ”