If nothing else, the seemingly unquenchable speculation about the "truth" of Barack Obama's birth is entertaining.

Like a fungus, speculation about whether Obama is a natural-born American surfaces, is eradicated, then somehow surfaces again. The issue, a favorite of conspiracy theorists who now are called "birthers," centers on whether Obama was born, as he says, in Honolulu on Aug. 4, 1961, at Kapi'olani Hospital.

Obama has produced a standard birth certificate copy issued by the Hawai'i Health Department attesting to all that. And just this week Health Director Chiyome Fukino repeated that she has seen and verified the original, still in Health Department files.

Still not good enough for some.

All this would be silly if there were not a subtext that is a bit more serious. The speculation about Obama's birth status (the alternative theory is that somehow his mother made it from Hawai'i to Kenya to have her son) reveals that there are still many who cannot accept Obama as legitimately "American."

As he likes to point out, he has an exotic name, comes from an exotic background (born in Hawai'i, schooled for a time in Indonesia) and has an exotic genetic mix (half white, half African).

That's just too much, one suspects, for some people to handle. So they cling to absurdities, such as the theory that Obama was born in Africa, to deal with their discomfort.

If this were simply a preoccupation of folks on the fringes of the Internet, it would be relatively harmless. But the infection has spread to the mainstream media and even into the halls of Congress.

Television newsman Lou Dobbs, who insists he personally has no doubts about Obama's U.S. citizenship, nonetheless continues to broadcast stories about the controversy.

And Hawai'i Congressman Neil Abercrombie briefly ran into a buzzsaw on the floor of the U.S. House on Monday when he sought to introduce a resolution commemorating the 50th anniversary of Hawai'i's statehood. The resolution took note of Obama's birth in the 50th state.

Although the resolution eventually passed, there were some initial complaints that it was a backdoor attempt to get Congress on record as accepting the contested notion that Obama was born in the United States.

There's no question that Obama represents something quite different in American politics and in the presidency. His race and his background are totally unlike that of the 43 men who preceded him into the White House.

Psychologists sometimes describe this as an "us/them" syndrome. We look at someone and internally decide whether that person is one of "us" or one of "them."

In the case of Obama, a majority of Americans demonstrated with their vote that they accepted Obama — exotic as he might be — as one of "us." But it appears there are still some out there who view Obama as one of "them" — an alien, if you will.

It wouldn't do in this day and age, however, to specifically focus on the president's racial background or unusual upbringing.

So, as a substitute, people latch on to the matter of the birth certificate.

If you don't like that psychological theory, however, there is another.

Bill Pascoe, who writes a conservative blog for Congressional Quarterly Politics, suggests (perhaps with tongue in cheek) that the "birther" controversy might be a back-fire actually set by Obama supporters who are eager to portray the president's critics as wackos and looneys.

Pascoe worked against Obama in two campaigns and sees plenty of fault in the man. But the idea that Obama is foreign-born is not among them.

"Am I the only one to notice that mainstream media attention to the 'birthers' has picked up in recent weeks and this increased attention is coincident to the turn in Obama's approval ratings?" Pascoe mused.

So pick your theory: The "birther" syndrome is displaced anxiety over Obama's "otherness" or it is a clever political trick designed to keep the legitimate conservative opposition off its game.

Either way, it doesn't look to go away any time soon.