I'm not on the Fredwagon just yet, but I should point out that the President has absolutely no power to amend the Constitution, and no role in the process.
"Society has always regarded marital love as a sacred expression of the bond between a man and a woman. It is the means by which families are created and society itself is extended into the future. In the Judeo-Christian tradition it is the means by which husband and wife participate with God in the creation of a new human life. It is for these reasons, among others, that our society has always sought to protect this unique relationship. In part the erosion of these values has given way to a celebration of forms of expression most reject. We will resist the efforts of some to obtain government endorsement of homosexuality." -- President Ronald Reagan, July 12, 1984