THE AMERICAN-LED assault on Fallujah, a city the size of Newark, N.J., from which many have fled but where up to 100,000 residents may yet remain, is now gathering steam. It has three possible outcomes:
United States and allied Iraqi forces may succeed in smashing the armed insurgency there, and in doing so put all of Iraq on the road to an increasingly peaceful and political reconstruction.
The battle could be a protracted and bloody one, especially for civilians. This could test Americans' patience and ignite Iraqi outrage and disaffection, to the point that huge swaths of the country become engulfed in violence.
One side might decide not to show up. Insurgents may slink out of the city - many, perhaps, already have - to fight again another day, just as they did in Samarra last month.
The history of counterinsurgency wars, from Algeria to Vietnam to Chechnya, suggests that some combination of the second and third scenarios is the most likely. And the history of Iraq since March 2003 gives little reason to expect that the first scenario is even plausible.
The prime minister of Iraq, Ayad Allawi, has just announced a 60-day state of emergency - martial law, in other words - that will have no practical effect on fighters in Fallujah but will remain in force until just two weeks before scheduled elections. Baghdad airport was closed yesterday, as were Iraq's borders. Attacks were launched by insurgents in Ramadi and Baghdad. There were troubling reports of significant desertions among American-trained Iraqi soldiers about to be sent into Fallujah.
But the battle of Fallujah nonetheless presents an interesting possibility: No matter what actually happens there, Washington can declare a significant victory.
To be sure, Defense Secretary Donald H. Rumsfeld said yesterday that Fallujah will be just one step on a long and difficult road, but once the United States decides that Iraq is actually on that road, it would be a natural moment to begin turning over the dirty work to the Iraqis themselves. Whatever eruptions that occurred afterward would be regrettable, but not cause for an American return to the field.
This may seem an unlikely moment to be discussing an exit from Iraq, but President Bush's electoral victory gives him wide latitude to change course as he sees fit, and it has, significantly, allowed old-line conservatives to begin voicing their doubts about the war there. It does not, in fact, enjoy hearty support anywhere.
A military triumph in Fallujah is likely to be a transient one, at best, but if Iraqi forces under Mr. Allawi's government can be propped up for at least several months, it could become the fig leaf to cover a winding down of the American commitment to Iraq.