Very good point from atrios . Now it is absurd for me to link to Atrios.

Recall the Musgrave proposal

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.

Atrios argues that
"...the truth is, of course, that the amendment actually outlaws all new marriages."

Indeed, there is no exception in the amendment that states "unless this unmarried couple are a man and a women who are currently not married to anyone else and are engaged to be married". I'm not sure it would be unconstitutional to issue marriage licences, but if some official decided not to recognise a marriage he would not be violating any constitutional law.

Let's say San Francisco (for example) decides to treat same gender and different gender couples, who were not married when the amendment was ratified and claim to be married, in exactly the same way. Currently that would be a violation of California law, which establishes rights for married couples and conditions for legal marriage. Those laws would clearly be unconstitutional. "Unmarried couples" means "unmarried couples" and allows no exception for a man and a women who are currently single and agree to marry.

OK that would be extreme for San Francisco or even Provincetown ? How about some weirdo local (or state) government 100 years from now ?