FF&C is utilized mainly in law enforcement and judgments, not civil unions.
As for its application in records of marriage, it has precedent. Until the Supreme Court struck down all laws banning interracial marriage in 1967, a number of states banned interracial marriage and did not accept interracial marriage certificates issued in other states. The full faith and credit clause was never used to force a state to recognize a marriage it did not wish to recognize.
Between 1996 and 2004, 39 states passed laws (9 states) and constitutional amendments (30 states) that define marriage as consisting solely of different-sex couples. Most explicitly prohibit the state from honoring same-sex marriages performed in other states and countries. That's a LOT more than half of the states expressly addressing gay marriage.
Nine states have allowed gay marriage - Connecticut, Iowa, Maine, Maryland, Massachusetts, New Hampshire, New York, Vermont, and Washington. Do you think that Washington, DC, and these 9 states should overrule the state amendments of over 30 states? What kind of "United STATES" is that?






