An exclusive report from Slate's guesswork unit.

It's probably only a matter of seconds before we find out which White House official insisted that the fateful yellowcake reference be inserted into the State of the Union address. We now know for certain somebody did because Sen. Dick Durbin, D-Ill., blabbed on Good Morning, America that CIA Director George Tenet dropped a dime on him (or her) in yesterday's closed-to-the-public hearing of the Senate Intelligence Committee. Hypocritically, Durbin refuses to say who it was, lest he violate the committee mandate for secrecy. Presumably one of the committee's other Democrats—Rockefeller, Levin, Feinstein, Wyden, Bayh, Edwards, or Mikulski—is even now whispering the name into the ear of an appreciative reporter. Or (more likely) a Senate aide is doing so. After all, there is no national-security rationale for keeping secret the identity of the Phantom Bigfoot. Nevertheless, the White House, unsurprisingly, isn't talking.

One likely suspect must immediately be crossed off the list: Deputy Defense Secretary Paul Wolfowitz. On Good Morning, America, Durbin said:

[T]here was this negotiation between the White House and the CIA about just how far you could go and be close to the truth, and unfortunately those sixteen words were included in the most important speech the president delivers in any given year.

Wolfowitz doesn't work at the White House. He works at the Pentagon. So Wolfowitz can't be PB.

Vice President Dick Cheney is a very likely PB suspect, having pushed the yellowcake story in particular, and rumors about Iraq's nuclear capability generally, more aggressively than anyone else in the White House. On July 14, Brian Ross reported on ABC World News Tonight that Cheney "played a key and personal role in pushing CIA analysts to confirm the Niger story." That jibes with the recollection of former diplomat Joseph C. Wilson IV,in a July 6 op-ed for the New York Times, that when the CIA sent him to Niger in 2002 to check out the allegation that Iraq had bought yellowcake there, it was because "Vice President Dick Cheney's office had questions."

But Durbin's dance of the seven veils seems to suggest it wasn't Cheney. Chatterbox deduces this from Durbin's response to Tenet's offer to resign (which Tenet has to know was rendered moot when he fingered PB). "The more important question," Durbin said, "is who is it in the White House who was hell-bent on misleading the American people, and why are they still there?" If PB were Cheney, there'd be a very simple answer to Durbin's question: He's still there because, among other reasons, he can't be fired. He was elected by the Am—er, the Supreme Court, and the only way he can leave is by resigning or getting impeached. Yellowcakegate doesn't really necessitate so extreme a punishment.

That leaves only one really logical candidate. Lewis "Scooter" Libby, Cheney's chief of staff, is probably best-known to the public as the Bush official whose former representation of fugitive metals trader Marc Rich caused momentary embarrassment when the departing President Clinton pardoned Rich, provoking an uproar. Libby is a red-meat Iraq hawk who, according to U.S. News & World Report, pushed Secretary of State Colin Powell very hard when Powell was preparing his speech to the U.N. Security Council laying out the evidence against Iraq:

The first draft of Powell's speech was written by Cheney's staff and the National Security Council. Days before the team first gathered at the CIA, a group of officials assembled in the White House Situation Room to hear Cheney's chief of staff, Lewis "Scooter" Libby, lay out an indictment of the Iraqi regime—"a Chinese menu" of charges, one participant recalls, that Powell might use in his U.N. speech. Not everyone in the administration was impressed, however. "It was over the top and ran the gamut from al Qaeda to human rights to weapons of mass destruction," says a senior official. "They were unsubstantiated assertions, in my view."

Powell, apparently, agreed. So one week before he was to address the U.N. Security Council, he created a team, which set up shop at the CIA, and directed it to provide him with an intelligence report based on more solid information. ... The team, at first, tried to follow a 45-page White House script, taken from Libby's earlier presentation. But there were too many problems—some assertions, for instance, were not supported by solid or adequate sourcing, several officials say. Indeed, some of the damning information simply could not be proved.

Sound familiar?

If Libby is PB, it's unlikely he acted without strong encouragement from Cheney. In addition, Chatterbox's friend Jason Vest, who writes about national security for TheNation and the Village Voice, urges Chatterbox not to forget that National Security Council staff aide Robert Joseph would be a logical person to have worked closely with Libby on this. Judging from the questions at today's White House press briefing, Joseph is the White House press corps' No. 1 suspect. (Weirdly, Libby's name never came up.) It's previously been reported that Joseph had a role in the negotiations between the White House and the CIA over putting yellowcake into the speech. Note this snippet by David Sanger and James Risen, from the July 12 New York Times: