There is no uniform position for primaries in the US for President. On one hand, you can say that is permitted under the Constitution by the Tenth Amendment. On the other hand, since we are electing a National President, shouldn't all primaries be similar? In essence that would come under the heading of "one man - one vote" Note: the question about closed primaries pertains to members of a political party. That is Open = anybody may vote in a party primary; Closed = Only members of a certain party may vote in that primary.