Now that the Labor Day weekend has ended, the big Iraq show will begin in the nation's capital.

Congress will receive a series of new Iraq assessments, leading up to the grand climax during the week of Sept. 10: congressional testimony by Gen. David Petraeus and U.S. Ambassador Ryan Crocker.

Then the drama will turn into political circus. President Bush will give an Iraq report to Congress on Sept. 15, setting off another round of debate on whether we should or shouldn't leave Iraq by 2008. This debate will be shaped — on both sides — more by election-year politics than events on Iraqi ground.

Both parties are expediting a worse Iraq disaster. The president wants to keep troops in Iraq as long as possible. The Democrats (and some Republicans) want to pull the plug — either quickly or more slowly.

So here's a plea. Can we please start thinking differently about this Iraq debate? Instead of stay or go, can we focus on preventing Iraq from collapsing when we ultimately leave?

Such a focus fits badly with the story lines of both parties. Republicans want to shift attention away from their gross mishandling of Iraq, so they pretend we can still establish Iraqi democracy and win a neat "victory." The stress on "stay the course" prevents an honest examination of how to salvage the best outcome we can.

Yet we all know the Pentagon can't indefinitely maintain current troop levels in Iraq, for reasons beyond domestic politics. Our armed forces are overstretched, the American public has soured on the war and many Iraqis have lost faith in our presence. That disillusionment can't be blamed on Congress; it results from years of glib administration claims belied by violence on the ground.

That said, those Democrats who argue that Iraq violence will ease when we leave are mistaken. Setting a timeline for complete withdrawal won't shock Iraqi factions or their Arab and Iranian neighbors into reconciliation. That's not how the Middle East works.

None of these factions trusts each other enough to make peace without strong outside involvement. U.S. leverage in Iraq has shrunk because of the mistakes of the past four years. If we set a departure date without proper preparation, our leverage will disappear.

Already, the debate over when to leave has provoked Iraq's Sunni and Shiite militias to start gearing up for all-out power struggles. Many Democrats say it's not worth staying on because the American presence won't make a long-term difference. They argue that Iraq's sectarian leaders appear determined to fight, so any U.S. military gains will prove fleeting.

But if U.S. troops leave without prior political arrangements in place, sectarian forces will rush to fill the power vacuum.

We pull our fingers from the dike and Iraq floods. That's almost for certain. So why aren't Democrats and Republicans trying to build up the levees before we go?

When Petraeus testifies before Congress, he will talk about military gains in Iraq at the local level, where many Sunni tribes, and some Sunni insurgents, have turned against al-Qaida.

He knows these gains must be consolidated. Those Sunni tribesmen working with our troops could morph into new militias who turn on the Shiite-led government (or U.S. forces). Nor has the progress with Sunnis yet led, as Petraeus hoped, to an overall lessening of Shiite support for their own militias.

Still, the general hopes that patches of progress in the provinces and parts of Baghdad can be knit together over the next year. If Sunni tribesmen are paid by the central government as auxiliary police, maybe resentment of the Shiite-led government will lessen.

Petraeus knows the surge must end. But he wants several more months to try to create a ragged Iraqi political quilt out of the current chaos. I don't know if these hopes will materialize, given the weakness of Iraq's political leaders. The chances of success would have been immeasurably higher had Petraeus been in charge in 2003.

However, I do know that too hasty a withdrawal will lead to disaster. This point was made to me quite passionately by a young former army officer, Kyle Teamey, who served in Ramadi in Anbar Province in 2003-04.

Teamey told me: "Congress is just debating whether to pull out or stay. But we should be trying to shape the outcome, trying to start shaping the chaos.

"We've seen what happens if we pull out rapidly without shaping things. Every time we've pulled out of areas where we've made progress like Mosul, Tal Afar, and parts of Anbar, they go to hell with mini civil wars."

So Teamey argues we should use however long we remain in Iraq to "try to build up local structures in large parts of the country, so we don't have utter chaos if the central government falls." He also hopes such structures would prevent an al-Qaida return to areas we leave.

This is one way to try to shape the chaos. There are others. One would be a robust effort at regional diplomacy to push Iraq's neighbors, for reasons of self-interest, to help stabilize Iraq. This would require an intense American diplomatic effort of a kind the Bush administration has so far avoided. But Teamey is right: We must try now to shape the chaos that will follow an American troop drawdown, or it will swallow us and the region. Will leaders of both parties be wise enough to attempt this? Or will the circus continue while Iraq goes down the tubes?

We must try now to shape the chaos that will follow an American troop drawdown, or it will swallow us and the region. Will leaders of both parties be wise enough to attempt this? Or will the circus continue while Iraq goes down the tubes?

Trudy Rubin is a columnist and editorial board member for the Philadelphia Inquirer. Reach her at trubin@phillynews.com.