IIRC, this was also a problem in 1952, with regard to Repub delegates from southern states that were solidly Democrat at the time.
I think it was key to Eisenhower getting the nomination away from Taft. There was a big floor fight over it at the convention.
Henry Cabot Lodge II was instrumental in it, and later boasted in Vietnam (where he was ambassador) that he had no problem with rigging elections there, since he'd done it in the US.
Meanwhile, we are stuck with a crowd who bitches about Dole, Bush, McCain, Romney and whoever is the RINO flavor of the cycle and have done NO MAJOR RULE CHANGES in the direction which I just suggested.