David Greenberg, a contributing editor to The New Republic, teaches history at Rutgers University and is at work on a history of presidents and spin.

The results are in: The electorate on the whole regards Barack Obama’s proclamation of personal support for gay marriage as a political maneuver, rather than an expression of heartfelt belief. Unfortunately, if Obama’s heavily hyped interview last week was in fact a political calculation, it was a bad bet—from a purely strategic standpoint, that is, not a moral one—since it seems to have hurt him in the polls. The giddiness and jubilation that marked the press coverage—see the covers of Newsweek and The New Yorker, which The New Republic all but predicted—could hardly be further from the mundane reception afforded the announcement by the general public.

Obama, of course, did the right thing. It’s high time a president endorsed equal rights for gays and lesbians, and whatever hit he suffers at the polls should earn him points for courage. But neither is it surprising that his interview has been greeted with cynicism. For his was a reluctant, narrowly framed, almost apologetic endorsement of same-sex unions—a far cry from the exercise in moral leadership from the bully pulpit that pundits have made it out to be....