Many conservative and libertarian bloggers have positioned themselves

in favor of a constitutional amendment mandating “federalism” with regard to gay marriage. Such an amendment would allow any state to recognize same-sex marriages or civil unions, but would prohibit courts to force other states to recognize those marriages via the Full Faith and Credit Clause of the U.S. Constitution. There’s some disagreement about whether the proposed “Federal Marriage Amendment” is such an amendment. Ramesh Ponnuru thinks it is. Eugene Volokh thinks it isn’t. But the only person I’ve read so far to propose a concrete alternative to the FMA is Keith Burgess-Jackson, who proposes the following Constitutional amendment:

Nothing in this Constitution shall be construed to require that a state recognize or give legal effect to marriages other than those between one man and one woman.

But if one’s sole motive to amend the Constitution is principled federalism, and not vile anti-gay bigotry, why the exception for marriages "between one man and one woman"? Why not the following Constitutional amendment?

Nothing in this Constitution shall be construed to require that a state recognize or give legal effect to marriages performed outside that state.

(Anti-miscengenation laws would presumably remain unconstitutional under the 14th amendment, so this amendment would not overturn Loving v. Virginia.)

According to this website, first cousins can legally marry in Massachusetts and seventeen other states (if I’m counting correctly). If the state of Kansas, for example, which does not permit first cousins to marry, is not required to recognize a same-sex marriage performed in Massachusetts, why should it have to recognize a cousin-marriage performed in Massachusetts?

And according to this website, people as young as age 14 can marry in several states, including Massachusetts. But in Nebraska, you have to be at least 17. If Nebraska is not required to recognize the marriage of two men from Massachusetts, why should it have to recognize the marriage of two 14-year-olds from Massachusetts?

If the proponents of federalism regarding marriage will endorse an amendment like this, I’ll not question their sincerity. (And if they’ll add a clause to the amendment stating the the Federal government will recognize any marriage performed in any state, overturning the odious "Defense of Marriage Act," I’ll even join them in endorsing it.) Until then, I’ll remain of the opinion that these proposals to amend the Constitution in response to the Goodridge decision have the stink of bigotry about them.