Senator John McCain of Arizona, one of six Republicans who opposed the measure, described the amendment regulating marriage - normally a state function - as "antithetical in every way to the core philosophy of Republicans" because it interfered with states rights.
I rather doubt that McCain used the expression "states rights," as opposed to "federalism" or some combination of words that does not immediately trigger thoughts about slavery and segregation. Of course, McCain himself seems not to have been willing to associate the Republican party with values of individual liberty and equality. A seemingly safe, nicely hedged position is to say that the matter ought to be left to the states--as if there weren't all sorts of problems involving persons marrying in one state and then moving to another.
Here's Maureen Dowd on the subject:
W. thought he had a bit in the maverick's mouth, but John McCain bit back, bolting over to the Democratic side to help embarrass the president by defeating the constitutional amendment that dare not speak its name. Senator McCain scorned the amendment banning gay marriage as "antithetical in every way to the core philosophy of Republicans." (Well, some Republicans.)
Dowd leaves readers to think that McCain might have actually expressed the idea that Republicans stood for values of individual liberty and equality, because it allowed her to portray McCain as a hero and the rest of the Republicans as louts. If she had wanted to portray all the Republicans as louts, she could have used the "states rights" move used in the news article, but she decided to go with the image of Bush the cowboy and McCain as the maverick, which is a type of horse, so the cowboy can be riding a horse, and then the horse "bit" Bush, which is funny because a horse wears a bit, and then that worked so well with the idiom of "bolting" the party, given that horses also bolt. If you don't like Dowd, this sort of compressed playfulness with language and imagery has got to drive you up the wall. But it actually is pretty clever.