Why is the ludicrous birther conspiracy theory so widespread? A Public Policy Polling survey this week showed that 48 percent of Iowa Republicans don't believe President Obama was born in the United States. Donald Trump’s potential presidential candidacy has support despite — or maybe because of — his “asking questions” about the president’s actual birthplace. In May, WND Books will publish “Where's the Birth Certificate?,” which, as I write, is No. 2 on Amazon.com. The author is Jerome Corsi, the man behind “Unfit for Command” and the “swiftboating” of John Kerry. The connection is important: “Birtherism” may be to the 2012 election what the Swift Boat Veterans for Truth were to 2004.

I reported on the Swift Boat vets at the time and found that, while most of their claims were unverifiable or wrong, they were right to say that John Kerry was not in Cambodia during Christmas 1968. The truth notwithstanding, the Swift Boaters had an impact on the election because their charges fed into a powerful current of opinion that regarded John Kerry as a mealy-mouthed politician who waved the bloody shirt when it suited him — after trashing his fellow veterans when that too was convenient.

Similarly, “birtherism” feeds into the belief that Obama is a prevaricator whose reputation is built on sand. The search for the hidden birth certificate is a synecdoche for the idea that Obama is not really “one of us.” I'm not even sure it’s all racial — it’s more that Obama is a member of the “ruling class” rather than the “country class.” After all, even the president’s supporters compare him to Mr. Spock. The endless birther speculation jibes with Dorothy Rabinowitz’s essay last year on “the alien in the White House”:

A great part of America now understands that this president’s sense of identification lies elsewhere, and is in profound ways unlike theirs. He is hard put to sound convincingly like the leader of the nation, because he is, at heart and by instinct, the voice mainly of his ideological class. He is the alien in the White House, a matter having nothing to do with delusions about his birthplace cherished by the demented fringe.

This is why the birther thesis endures despite pushback from opinion leaders. The particularities of Obama's birth certificate are part of a general critique of authority in which all elites are viewed as compromised and leading America to ruin. Donald Trump is benefiting at the moment because elites loathe him, he loathes them back, and he is attacking President Obama with a ferocity rarely seen from Republicans.

No matter how incorrect “birtherism” is, then, it should not be dismissed. The Swift Boat veterans didn’t have all their facts straight. Their tactics were somewhat underhanded. They were driven out of polite company.

And Kerry lost.