Sen. Marco Rubio, R-Fla., said he opposes a federal amendment on marriage, arguing that states should decide how to define the institution within their borders, though he stopped short of denouncing the Defense of Marriage Act (1996).

“I’ve always been uncomfortable with a federal constitutional amendment on anything, in particular on that, because I think it steps on the rights of states to define marriage,” Rubio said last night during Buzzfeed Brews, after remarking that states have “always decided it.”

Rubio and President Obama thus, as a legal matter, hold the same position on gay marriage insofar as they both say states should be able to decide the issue (though Obama “personally” supports gay marriage, while Rubio opposes it).

“That’s a two-way street, though,” Rubio said. “If states define marriage as between one man and one woman — if you’re going to say it belongs to the states, then you have to respect whatever decision they make. And that includes states like Florida that have passed a constitutional amendment that say marriage is between a man and a woman. And likewise you have states that are headed in a different direction.”

That might have been a shot at the president, who says that states should be able to decide the issue but criticizes states that decide the issue in a way that he does not approve.

“The president has long opposed divisive and discriminatory efforts to deny rights and benefits to same-sex couples,” Obama’s North Carolina campaign spokesman Cameron French said in May after that state passed a bill defining marriage along traditional lines. “He believes the North Carolina measure singles out and discriminates against committed gay and lesbian couples, which is why he did not support it.”

Rubio stopped just short of saying he opposes DOMA, calling the legal challenge to the law “a very interesting constitutional question” about “whether the federal government needs to recognize a state’s definition” — a comment that, given his earlier remarks about states “always” deciding how to define marriage, would suggest he opposes DOMA.

If Rubio runs for president — he said last night that he’s focused on his job in the Senate — it’ll be interesting to see how his position plays in Iowa, where three Supreme Court judges lost there reelection bids in 2010 because of a “ruling that made Iowa the first state in the Midwest to sanction same-sex marriage,” according to USA Today.

The potential presidential candidate will have the advantage of agreeing with many of those Iowa voters on how marriage in their state should be defined.

“I believe marriage is a unique and specific institution that is the result of thousands of years of wisdom, which concluded that the ideal — not the only way but certainly the ideal — situation to raise children to become productive and healthy humans is in a home with a father and mother married to each other,” Rubio told Christianity Today. “It’s not a discriminatory thing. I’m not angry at anyone because of it, but I also have to be honest about what I believe marriage should be in our laws.”