No one I've read on this gay marriage question seems to be making the obvious (to me) point that if the administration is going to send a pre-election signal in favor of gay marriage, it's far better for Joe Biden to do it than for Barack Obama to do it.

Biden is Catholic. He has that working-class, Pennsylvania-style cred. It's far, far better for Americans to hear that kind of talk from him than from Obama, the black urban liberal cosmopolite. So I'm not so sure this was a gaffe. Or if it was a gaffe, it may have been a happy one.

I wrote a column about six weeks ago arguing that Obama should not endorse gay marriage before the election, for various political reasons, mostly because the majority that supports same-sex marriage seems a little fragile to me as yet. Liberals like to say, "But it's the majority view, and it's what he believes, so what's the problem?"

But that's really simplistic politically. I'd want to know a lot about how that position sits with various voting blocs in Pennsylvania, Michigan, Ohio, Virginia, Colorado, North Carolina, and Florida. I'd want to know what voting blocs a pre-election public embrace would be more likely to motivate in all those states (and some others). For example, the fact that there is simple majority support in America (and it's not a huge majority by any means--53, 54 percent) might mean that quite large majorities in a handful of already-blue states support gay marriage. But that would have nothing to do with how independents in Virginia feel. And this is the important point: Wanting to know such things before acting isn't political cowardice. It's pollitical horse sense.

Win the election first. If it appears in September that Obama can win while supporting same-sex marriage, then maybe he should pull the trigger. There are upsides. But if it appears that it will motivate chiefly voters on the other side, it can and should wait. It would be something he could take on early in a second term, and while the wingers would howl, most of America wouldn't bat an eye.

Right now, Obama has the advantage over Romney on this issue. Slate's Dave Weigel picked up today on how RNC Chair Reince Preibus is trying to say there's no difference between Obama's and Romney's positions, an argument that Weigel shredded: Romney has signed the National Organization for Marriage's five-point reactionary pledge, and virtually each point stakes a position the opposite of Obama's.

So the Republicans are on the defensive today, aware that their candidate's posture is out of the mainstream. There's no pressing reason for Obama to upset that balance.