The only reason for her meaningless change of heart is that her N.O. Morial machine / 9th Ward safety net is gone. She isn't going to win any more close elections without radically changing some of her positions and convincing voters that she's genuine.
She's changing her position because the vote was going to fail anyway. Political posturing at its worst. Much like the introduction of this bill right on the heels of the Senate voting for Amnesty.
She voted "NAY", so she voted with the rest of the Donk's.
I called Landrieu's office a few days back to inquire how she was going to vote. The intern answering the phone said that Landrieu was going to vote against the marriage amendment because it was unnecesary, since Louisiana already had a state constitutional amendment protecting marriage.
It didn't matter to Landrieu that an activist federal judge can deem our state amendment unconstitutional.
In other words, Landrieu is for counterfeit marriage.