I feel that a lot of folks here are going to be somewhat disappointed when the President explains that his remarks are intended only to keep gay marriage from spreading. I really can't see how the Federal government can compel a State to define marriage according to a national standard, without the withholding of funds related to the institution, much the same way highway funds were withheld to get a 55 MPH speed limit some years ago.
Certainly, sending troops in to Massachusetts to arrest Supreme Court judges (maybe I'm reading too much into one of your "options") would hand a massive campaign issue to Kerry, presuming he becomes the nominee. No, if the President is going to go nuclear (or, "nucular", as he likes to say) on gay marriage, he'll do it after the election, which means there will be several thousand gay couples bearing Massachusetts marriage certificates between May and November. He'd better hope he's the winner of that election when he goes to act, if he intends to do so.
I just see him saying what makes the majority of Americans feel comfortable, without really pushing the issue that much. He'd be smart to let Kerry spend way more time talking about gay marriage than he does.