Liberal hindsight about September 11th has degenerated to the level of barroom conversation.

“I didn’t believe that the attack on the World Trade Center could have been prevented when we started this investigation,” says Bob Kerrey, who has become de facto commission chairman. “After studying the details for six months, however, I now believe it could have been stopped.”

After studying for six months, Kerrey could probably carry on a brief conversation in Farsi as well. But is that any proof that he could have read the future?

The most shameless meanderings came from Nicholas Kristof in last Saturday’s New York Times. “The 9/11 attacks could have been prevented,” Kristof announced with admirable finality in a column entitled, “Why Didn’t We Stop 9/11?” He then went on to imagine the conversation that should have taken place on August 6, 2001, after a CIA briefer informed President Bush that Osama Bin Laden was hoping to hit targets in America:

Bush: Any idea where?

C.I.A. briefer: Sir, it could be almost anywhere, anytime. But pattern analysis suggest a target both huge and symbolic, perhaps another explosion to topple the World Trade Center, or the Sears Tower, or the Capitol. And Bin Laden has always looked for targets in aviation.

Bush: Gosh. Hijacking airplanes?

Briefer: Yes, Mr. President, there are reports of a hijacking plot to ransom the blind sheik. . . . Or he could blow up planes and airports. . . In 1995 . . . we let Philippine police interrogate [Abdul Jalm] Murad… a key figure in a plot to blow up as many as 12 United Delta and Northwest jumbo jets over the Pacific Ocea.… After he’d been beaten with chairs, burned with cigarettes and half-drowned, he disclosed a plan for a suicide airplane attack on the C.I.A.’s headquarters.

Bush: You mean using a plane as a missile? . . . If the Big Beard is into aviation, let’s watch flight schools and airports.

And so forth.

All this reminds you of that old New Yorker cartoon where one barroom orator announces to another, “And how come we’re not sending men to the moon anymore, either?” Rather than tutor these people in history, let’s just finish off Kristof’s conversation for him:

Bush: So who do you think Osama’s got working for him here?

Briefer: Well, you know that Mohammad Atta guy down in Florida, the real surly one? We figure he’s probably involved.

Bush: Yeah, I never liked that guy.

Briefer: He’s living in Miami, but we figure that’s a ruse. He’ll probably hijack the plane somewhere up north, maybe around Boston.

Bush: When do you thing this thing will happen?

Briefer: They’ll probably wait until September when people are back from vacation and the buildings are packed. Tuesdays are a slow flying day. They’ll probably pick the first Tuesday in September.

Bush: September 2? No, that’s too close to Labor Day. It’ll probably be September 11th.

Briefer: That’s a better guess.

Bush: So let’s go out and arrest him right now!

Briefer: Well, Mr. President, there’s a problem. They haven’t done anything wrong yet. The Fourth Amendment says you can’t start investigating people until there’s probable cause that they’ve committed or are about to commit a crime. All we’ve got now is that these guys are Middle Easterners who’ve been taking flight lessons. If we try to move now, that would be racial profiling. You wouldn’t want to do that, would you, sir?

Bush: Gosh no, I guess you’re right.

Briefer: So what do you want to suggest?

Bush: I’ve got it! They’re going to hijack the plane out of Boston on September 11th, right? Let’s take Air Force One and cruise the area that morning. As soon as we see a plane divert toward New York, well turn on our flashing lights, force them to land at Newark, read ’em their rights, and arrest them on the spot. That way we can stop the whole thing without violating the Constitution.

Briefer: (high-fiving). Mr. President, you’ve got it! All system go! We’ll see you the morning of September 11th!