The Constitution exists to limit governments, not individuals -- this is a stupid idea. You don't write laws with the Constitution.
I responded by pointing out that Amendment XIII DOES limit individuals (by prohibiting them from engaging in slavery) and DOES write a law into the Constitution.
The Federal Marriage Amendment would hardly be an assault on freedom. Homosexuals (and everyone else) would still be able to do whatever they want in their private lives. The amendment simply states that, as far as the U.S. is concerned, marriage is legally defined as a union between a man and a woman, and courts may not impose another definition of marriage on the populace. Again, here is the text of the amendment:
Marriage in the United States shall consist only of the union of a man and a woman. Neither this constitution or the constitution of any state, nor state or federal law, shall be construed to require that marital status or the legal incidents thereof be conferred upon unmarried couples or groups.