[OldDeckHand]

"States do not have the power to redefine marriage to suit themselves. What was sauce for Utah is sauce for Massachusetts."

Boy, you and your "sauce". You still haven't cited specifically where this "sauce" may be found.

If states "don't have the power to define marriage", why do some states - like NY - allow 1st cousins to marry, but other states like AR and KY, they can't? How about that "sauce".

[BenKenobi]

Reynold's confirmed that the Federal government had the authority to require Utah to conform to the common law definition of marriage between one man and one woman. Again, the definition of marriage doesn't change in your example. Just the specifics. States have the authority to change their ages of majority. Redefining marriage, in changing the one man, one woman formula, is not permitted. It's never been a state right to redefine, else Utah's polygamy ban would have been thrown out by the SCOTUS. Instead, it was affirmed by appealing to the English common law traditions well older than the constitution.