If Pres. Bush doesn't support stopping this slide into Sodomite Hell via a Constitutional amendment, he doesn't deserve to be President, and say hello to Pres. Kerry Congress is the body who sets the constitutional amenmdment bandwagon going. The President has nothing to do with it.
But you already knew that.
If Bush can push Congress into a $540 billion dollar Medicare bill, he can do the same with Constitutional Ammendemnt defending traditional marriage.