President Bush and Vice President Cheney cannot make the case that their Iraq policies have succeeded, so they are doing one thing they do very well: taking a serious argument over the future of American foreign policy and turning it into a petty partisan squabble.

This is not really an argument over the "surge" of troops into Iraq. It is a fight over whether we want to make an open-ended commitment to keeping combat forces in Iraq for many years or whether we anticipate pulling most of them out within a year or two.

Even if the surge succeeds in a narrow sense -- by reducing the number of Iraqis killed in sectarian violence in Baghdad -- there is no guarantee that the overall situation in Iraq will be any better, no guarantee that Iraqi leaders will take the political steps necessary to end the internecine killing and create a stable government, no guarantee that we will make progress against al-Qaeda.

Although he conveniently appeared in Washington as Congress was voting on war appropriations, Gen. David Petraeus, the top U.S. commander in Iraq, did not play politics Wednesday in assessing the situation there. He spoke, rightly, of progress in Anbar province, a Sunni stronghold, but added: "The ability of al-Qaeda to conduct horrific, sensational attacks obviously has represented a setback and is an area in which we are focusing considerable attention."

The president's comments this week were less measured. "I will strongly reject an artificial timetable withdrawal," Bush said, "and/or Washington politicians trying to tell those who wear the uniform how to do their job."

Let's parse that statement. The notion that Congress has an "artificial timetable" suggests there must be such a thing as a "natural timetable." But what would that be? Presumably, the president would reply: when we achieve victory. But what is the definition of "victory" in the murky mess we're in? The administration offers only generalities that lead us nowhere.

And it's beyond chutzpah for a politician who has lived at 1600 Pennsylvania Ave. for more than 2,280 days to attack "Washington politicians." Didn't Petraeus get his orders to pursue the surge from a certain Washington politician otherwise known as the commander in chief?

Or take Vice President Cheney's statement on Tuesday: "Some Democratic leaders seem to believe that blind opposition to the new strategy in Iraq is good politics." Cheney assumes that opposition to the administration's policies must be "blind" rather than a considered, rational response to four years of failure. And the opposition must be rooted in "politics" and not in principle, presumably because reasonable people cannot possibly have good cause for disagreeing with the administration.

What Bush and Cheney are doing is not just wrong. It's dangerous. If they were interested in success in Iraq, they would have turned down the partisan rhetoric long ago. A substantial majority now opposes their policies. The last thing the administration needs is more polarization, which clearly has not worked in its favor.

The president needs to convince Americans that a decent result in Iraq is still possible. Above all, he needs to answer the essential question: If we shouldn't have timetables now, how long does he think we'll need to keep combat forces in Iraq? Two years? Five years? More? And to what end?

With the president set to veto the supplemental spending bill that includes calls for withdrawal, the whole burden of proof in this debate should change.

The burden should no longer be on those who say we are reaching the limits of what military force can achieve in Iraq -- partly because we never sent enough troops in the first place and also because our military is stretched to the breaking point, limiting how many forces the Washington politician in the White House can offer Petraeus.

Instead, the burden of proof should be on those who have offered years of bravado and false optimism. Why are Americans supposed to believe Bush's current claims? Why shouldn't Congress continue to pressure the president to bring our combat troops home on a reasonable schedule? And why doesn't the president start talking seriously to Congress instead of just shouting at Democrats?

Pretending he is in the middle of an electoral campaign will do nothing for Bush if what he wants is to rally the country behind a sensible way forward in Iraq. Petulance isn't working, and before long many Republicans who have stuck with the president so far will run out of patience.

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