Amending the US Constitution to prohibit gay marriage?

Apparently, US Christian conservatives want to have the US Constitution amended to prohibit gay marriage. They'd like to see an amendment preventing consenting adults from legally committing to each other right alongside freedom of speech, abolishing slavery and granting women's suffrage.

I came across this while reading through a conservative message board (it's like watching a car crash, you don't want to look, but at the same time it's morbidly fascinating).

Here are some of the comments on the message board supporting this proposal:

• "Same sex marriage is only a step in a vast plan to pervert society. Anyone who thinks otherwise, isn't paying attention." Yep, there's a whole bunch of gay people who do nothing but plot and scheme to turn society gay. All they care about is getting in your heterosexual pants. Sure.
• "Until there is an amendment, there will be a real risk that the liberal bloc of the Supreme Court will impose on all of us its own view of how society should be ordered" And as we all know, only the conservative bloc of the Supreme Court should be able to impose it's view of how society should be ordered on everyone.
• _"_A protection of marriage ammendment would stop government from imposing sodomite marriage on us." Because if gay marriage was allowed, then everyone would be forced to take it up the ass?
• _"_Since we have the right to freedom of religion, and forced recognition of sodomite marriage would violate that right, a Constitutional ammendment barring government from recognizing sodomite marriage is legitimate." So allowing two men to marry somehow violates your freedom of religion? It somehow forces you not to be Christian anymore? Riiiight. Does allowing atheists to marry violate your freedom of religion as well?