Schumer's position is that the federal Constitution does not require same-sex marriage or the recognition by one state of another state's same-sex marriage. In other words, that DOMA is constitutional and sufficient. He said that earlier in the week. What he basically wants to convey is that the Federal Marriage Amendment is unnecessary. Whether or not he has ulterior motives (no doubt) is another matter altogether.
Chuckie also said that the gay marriage issue was fair game to question a judge on. (Chuckie's never been noted for consistency). If Chuckie does this then no matter how it actually goes down it will look like he wants a pro gay marriage justice. A little spinning will help reinforce this perception.