Mystifying.

Republican presidential candidate Marco Rubio said Wednesday he would oppose a constitutional amendment allowing states to ban same-sex marriage after the Supreme legalized it nationwide, even though he disagrees with the landmark 5-4 decision.

“I don’t support a constitutional amendment. I don’t believe the federal government should be in the marriage regulation business,” the Florida senator told reporters after a speech the Cedar Rapids Country Club in Iowa.

“We can continue to disagree with it. Perhaps a future court will change that decision, in much the same way as it’s changed other decisions in the past. But my opinion is unchanged, that marriage should continue to be defined as one man and one woman. The decision is what it is, and that’s what we’ll live under,” he said.

He said after the Obergefell decision came down that it should be respected as the law of the land, an orthodox position on a Supreme Court ruling but one which got him smacked around by social cons who accused him of caving too quickly to judicial tyranny. The solution to that political problem was obvious: He could endorse a constitutional amendment to overturn the decision, which would itself become the superseding law of the land. His friends in the donor class might grumble at an amendment that would seek to ban SSM outright but they’d surely be okay with one that proposed letting states define marriage within their own borders. It’s a federalist compromise on the issue, one that would allow state majorities to legalize gay marriage on their own without Republicans standing in their way. And it has zero chance of being ratified given the Democratic numbers in Congress so there’s no real political cost for someone who’s on record as backing traditional marriage to support it. Scott Walker and Ted Cruz have already endorsed the idea. All Rubio would be doing would be joining them.

Yet he refuses. I could understand if he justified his position by saying “an amendment will never pass” — that would at least be true, if not politically astute — but he’s not saying that. Instead he gives the bizarro reason that “the federal government should [not] be in the marriage regulation business,” which is … exactly what many conservatives have said in criticizing the Supreme Court’s decision. The Court’s part of the federal government and they’ve now imposed a coast-to-coast regulation on marriage. If you don’t believe the feds should be messing around with this subject, you should support returning the matter to the states, no? Rubio’s tactics are usually lucid but I don’t get why he’d go this route, unless he thinks that mere rhetorical support for a longshot amendment will be such a liability in the general election that he’d rather stay away from it in the primary. And if he feels that strongly, why continue to defend traditional marriage at all? Why not just “evolve” and be done with it?

In lieu of an exit question, on a semi-related note, enjoy the tweet of the day from Slate’s Will Saletan: