The latest outburst of what Richard Hofstadter famously called "the paranoid style" in American politics is the absurd controversy over President Barack Obama's birth certificate. For months, a bizarre story has been circulating that the documentation of Obama's Hawaiian birth is incomplete or forged or otherwise defective, and that he was really born in Kenya.

This claim is obviously crazy on its face. Among many other things, to accept it one would have to believe that his parents spent decades lying about the birthplace of their son for no discernable reason, and that the announcement of Obama's birth in the local Honolulu paper the following week is also a forgery.

Thus the rumor was mostly confined to conspiracy-minded Internet sites, right-wing talk radio, and professional lunatics like Alan Keyes (Obama's Republican opponent in the 2004 Illinois senate race).

In the last few days, however, this preposterous nonstory has been given a bit of life as a supposedly legitimate subject of journalistic inquiry. In the Los Angeles Times, Andrew Malcolm quoted some of Keyes' ravings on the subject, and claimed they had put the controversy "back on the burner," and that "the simmering dispute seems unlikely to evaporate any time soon."

Then Alabama Sen. Richard Shelby got into the act. When a constituent asked him what he thought about the claim that Obama wasn't constitutionally eligible to be president, Shelby replied, "Well his father was Kenyan and they said he was born in Hawaii, but I haven't seen any birth certificate. You have to be born in America to be president." (A spokesman for Shelby subsequently claimed the senator's statement had been "distorted," because it had only been a "throwaway line," whatever that means.)

Of course the logic of conspiracy theories is such that there is literally no evidence that can be produced to dissuade believers in such theories. When the Obama campaign released a copy of Obama's certificate of live birth, this was almost instantly discovered to be a forgery by true believers, who immediately started demanding that the campaign release more documentation.

In short, this phony controversy will never go away, any more than wacky theories about the World Trade Center being leveled in a controlled demolition will ever go away. The interesting questions are, why do people like Shelby, and talk-radio types like Rush Limbaugh, who, unlike Keyes, almost certainly aren't delusional enough to buy into this nonsense, give it any credence?

The answer, I suspect, is that while Shelby and Limbaugh don't believe for a second that Obama wasn't born in the United States, they find it both politically useful and psychologically satisfying to question the legitimacy of Obama's presidency.

This is a dangerous game, given the nontrivial numbers of unbalanced people out there who are only too willing to believe that a black man with a Muslim name can't possibly be the real president of the United States.

The appropriate role of the media in all this is clear. First, we should point out that the "controversy" over Obama's birthplace is completely fake, because his place of birth is as well-documented as that kind of fact can be.

Second, we should emphasize that anyone who claims to believe Obama wasn't born in Hawaii is either a Keyes-style nut or a shameless opportunist who is willing to fan crazy and potentially dangerous rumors for political gain.

Third, we should criticize any journalist, like Malcolm, who engages in "balanced" reporting of the "some say the Earth is flat, others that it's round, and I'm just describing the controversy" type.

At times, journalism requires pointing out that some people are crazy, others are not, and that, in a dispute between crazy and sane people, the truth is not going to end up lying somewhere in the middle.

Paul Campos is a professor of law at the University of Colorado. He can be reached at paul.campos@colorado.edu.