It's official: When Dick Cheney meets the 9/11 commission, he will be accompanied by his personal chauffeur, George W. Bush. The arrangement is a coup for the commission. Eavesdropping drivers often recall details that harried execs have forgotten. "Bush," as he's affectionately called, may fill in the gaps on awkward matters which Cheney "forgets."

As Somerby says "The arrangement simply cries for parody," and Billmon has a nice skit featuring a foot-stomping, finger-twitching Cheney signaling Bush the right responses:

Kean: Commissioner Ben-Veniste, you may begin.

Ben-Veniste: Mr. President, what did you know and when did you know it?

Bush: Say what?

Ben-Veniste: (chuckles) Sorry, Mr. President. I couldn't resist that one. (clears throat, grows more serious) Mr. President, you were inaugurated as president on January 20th, 2001, were you not?

Bush: (evasive) You mean as president of the U.S. of A.?

Ben-Veniste: Yes sir, that's right.

Bush: Well, I, that is, um ... I think ... (Cheney loudly stamps his foot under the table, twice)

Bush: (carefully pronouncing each word) Yes, Commissioner, that statement is correct.

Ben-Veniste: And as president, you bear the ultimate responsibility for your administration's performance, do you not?

Bush: Responsibility? I'm not sure I like the sound of that ... (Cheney loudly stamps his foot, once.)

Ben-Veniste: (annoyed) Is something wrong, Mr. Vice President?

Cheney: It's just my foot, Commissioner. I'm afraid it's gone to sleep. (stamps it again, once.)

Bush: (slowly and precisely) No Commissioner, I must disagree with you about that.

Ben-Veniste: About what?

Bush: What?

Ben-Veniste: You must disagree about what?

Bush: (flustered) Whatever you just said, that's what.

(Maybe, given Bush's background with the Texas Rangers, Cheney will choose to use baseball signals to communicate with his protege -- you know, wipe across the chest, tap on the head, touch the nose and chin three or four times in alternation, then clap your hands and make a "swing away" motion means: "Don't answer that question: your political life depends on it".)

But in all seriousness, Josh Marshall correctly analyzes what the joint appearance really means:

Only three scenarios or explanations make sense to me.

The first -- and most generous -- explanation is that this is simply another way to further dilute the Commission's ability to ask questions.

If, say, the meeting lasts three hours, that's three hours to ask questions of both of them rather than three hours to ask questions of each -- as might be the case in separate meetings.

That wouldn't be any great coup for the White House. But it would be one more impediment to throw in front of the Commission's work, which would probably be a source of some joy for the White House.

From here the possible explanations go down hill -- in every respect -- pretty quickly.

Explanation number two would be that this is a fairly elementary -- and, one imagines, pretty effective -- way to keep the two of them from giving contradictory answers to the Commission's questions. It helps them keep their stories straight.

(It's a basic part of any criminal investigation -- which, of course, this isn't -- to interview everyone separately, precisely so that people can't jigger their stories into consistency on the fly.)

The third explanation is that the White House does not trust the president to be alone with the Commission members for any great length of time without getting himself into trouble, either by contradicting what his staff says, or getting some key point wrong, or letting some key fact slip. And Cheney's there to make sure nothing goes wrong.