He was in the position of the old-time pol who said, "Some of my friends are for the bill, and some of my friends are against the bill, and I'm always with my friends."
Particularly the friends with money. The Washington Post reported that one of out six Obama "bundlers," people who bring in large amounts of campaign dollars, identify themselves as gay.
Probably not all of them consider same-sex marriage a top-priority issue. But many undoubtedly do, and Obama has surely heard from them at the fundraisers he so frequently attends.
On another issue, Obama sided with rich liberal contributors by blocking construction of the Keystone XL pipeline to bring Canadian oil to the United States. He did so even though energy is a big issue and large majorities of voters favor the pipeline.
On same-sex marriage, the political calculation is closer. For one thing, it's a low-priority issue for most voters.
I think Obama's switch will help him significantly with young voters. And he has been doing conference calls with black ministers to mollify them in the hope they'll turn out their followers despite his stand.
But Gallup reports that 26 percent of voters say they're less likely to vote for him because of this issue, exactly twice the 13 percent who say they're more likely to do so.
And the CBS/New York Times panelback showed 67 percent saying he made his decision "mostly for political reasons," while only 24 percent say he did so "mostly because he thinks it is right."
That's a harshly negative result. It suggests that most voters see the president, on this issue at least, as opportunistic rather than sincere. That's good reason for panic.