Everyone loves a good conspiracy theory, if for no other reason than to coat the theorist with a glaze of crackpottery. And the internet abounds in such fractured terracotta. Let the President gag on salty snack food and a dozen web sites sprout overnight to spout, "Clandestine Cabal Conspires to Choke Chief!"

The latest plot premise to resurface, after a seven-year hibernation, is that Timothy McVeigh cahooted with Muslim militants when he destroyed the Alfred P. Murrah Federal Building and 185 people in Oklahoma City. The London Evening Standard reports that former TV talker Jayna Davis has in turn used reams of evidence to destroy the official finding that the deed was done solely by a pair of perverted patriots, McVeigh and Terry Nichols.

The evidence is supposedly so compelling that "several senior members of Congress" are elbowing the FBI in the ribs to reopen the case. But the problem here is that one conspiracy begets another. Say there really was a nefarious scheme involving, as the Evening Standard article sweepingly embraces, Arabs, Iraqis, Palestinians, al Qaeda, the PLO, a Saudi refugee, a dark-haired suspect known as John Doe 2, "Middle-Eastern looking men fleeing in a brown Chevrolet truck," and sightings at a local motel of "Mohammed Atta and Zacarias Moussaoui, the so-called 20th hijacker, who has known links with shoebomber Richard Reid."

(Beware of conspiracy spinners bearing "links" to terrorists. Under the Six Degrees of Separation hypothesis we're all linked to terrorists.)

But if any of these links are true, it can mean only one of two things for the FBI. Since the G-men initially sniffed at the trail of foreign terrorists before lifting their snouts once Nichols and McVeigh were quickly wrapped up in pretty bows, it means they're grotesquely incompetent. As for the other possibility . . . I can already hear cracked crockery web sites clicking open: "FBI Commits Massive Terrorist-Link Cover-up!"

So why would our ruling classes crack open a case that could only expose one of their own beloved bureaucracies to charges of incompetence, or worse? Maybe it's because one conspiracy begets another begets another. Is it mere coincidence for an Iraqi-based conspiracy to materialize just when Mr. President is desperately searching for a plausible excuse to blackjack Iraq? As the Evening Standard story explains it, the Doers of Evil tied to McVeigh are not just Muslims but Iraqis, not just Iraqis but former Iraqi soldiers, not just former Iraqi soldiers but one-time members of Saddam Hussein's elite Republican Guard. Smoking gun! If the conspiracy is true it's the perfect justification for war. If the conspiracy is bogus it's the perfect pretext for war.

So the FBI can be sacrificed. They've already been exposed to charges of incompetence, or worse, by the September 11 attacks. Where better to dump political garbage than an already established landfill?

Could the Muslim-McVeigh conspiracy be true? History is littered with proven plotters since Eve and Jake the Snake colluded to set up Adam in the apple caper. Medieval kings were de-crowned by the dozens by throne room connivers. Abe Lincoln was gunned down as part of wider intrigues. No one seems to deny the collective eradication of the first Caesar. (Brutus and the boys, it seems, weren't quite quick-witted enough to convene a blue ribbon commission guaranteeing a "lone knife-wielder assassin" theory, thereby covering one conspiracy with another.)

Are libertarians just being cynical to suspect that a Compassionate Conservative president might use a contrived conspiracy to launch a war? Try history again. Remember the Maine? Well, probably not. It was 1898. The US battleship Maine blew up in Havana harbor in the midst of territory-grabbing jingoists' demands for war with the doddering old Spanish Empire. The claim for blame fell mainly on Spain and the war was on. (The sinking is still unexplained.) President: William McKinley. Remember the Tonkin Gulf Incident? Maybe not. It was 1964. A Washington Post headline blurted, "American Planes Hit North Vietnam After Second Attack on Our Destroyers" while the New York Times reported US retaliation following "renewed attacks against American destroyers." But there never was a "second attack" or "renewed attacks." There was only a craving by bloodletters to expand the Vietnam War. President: Lyndon Johnson.

Maybe it's time to heed the warning of columnist Sydney Schanberg: "We Americans are the ultimate innocents. We are forever desperate to believe that this time the government is telling us the truth."

Bona fide conspiracy? Phony conspiracy? Or will only our great grandchildren know for sure?