Behold Moqtada Sadr, the true ruler of what remains of Iraq. At present, Sadr is being challenged: the Sunnis have stormed his health ministry and bombed his stronghold. So now he's pulled rank on Nouri al-Maliki. His followers are threatening to walk out of Parliament if Maliki meets with Bush in Jordan as scheduled.

Smart move, Moqtada. Leaving Bush high and dry in Amman would stick a thumb right in the White House's eye -- the government that nearly 3,000 Americans have died for would be snubbing its benefactors. It's extremely hard to see how Maliki can acquiesce, which I gather is Moqtada's ploy. If Maliki calculates that he can't afford to snub the president, he will cut himself off from the rising Shiite power at a time when the Shiites are under tremendous threat. The question before Maliki is probably the most important he has ever faced: does he insult the Americans or his own Shiites? Whatever Maliki does, he will forfeit what remains of his political profile, and will be revealed either as Moqtada's man, or Bush's.

Look to this as the start of the end of Maliki's tenure as PM. An overwhelming 74 percent Shiites want the Americans out within the year. If he goes to Jordan, the Shiites don't need to believe in Moqtada to see Maliki as the wrong man to deliver the end of the occupation. If he doesn't, the calls will come out, loudly, in the next Congress that not another drop of American blood should be shed for the catspaw of Moqtada Sadr, or for a political process that is bending in Sadr's direction instead of the U.S.'s. I really can't overemphasize how smartly Sadr is playing this.