Apparently Ron Paul is also wrong on the need to protect marriage federally. He is against the federal marriage amendment, on faulty grounds.
Marriage is a federal issue, ever since Congress required states to disavow polygamy in order to join the union.
I dunno, I'd rather the Feds not be involved in marraige. Just like religion, they corrupt whatever they touch. There are currently many perverse incentives and disincentives involved in family and marriage that are the direct result of federal intervention.
Persosonally, I'd even prefer local governments out of the debate. Let the people themselves define marraige. Not sure why this idea appears so radical...