HOW THE CONSTITUTION DESCRIBES PRIMARIES!
It doesn't! There is no reference whatever to primaries or how parties, which are likewise never mentioned, can select their candidates. In fact most of the Founding Fathers objected to parties altogether. Some conclude that Andrew Jackson was the originator of a political party system.
So if Americans as a whole are so turned off by the primaries and political parties as they currently exist, is it not time to suggest Constitutional remedies for the concept of the two party system and the amazing amount of money that is spent by the parties? The reality is that in order to get an amendment through to ratification, there would have to be support for the change from one if not both political parties. Its kind of like drinking you own poisoned wine.