After spending $25 billion or so to rebuild Iraq's army, those troops still aren't able to stand up so U.S. troops can stand down.

Sectarian violence still flares; Iraq's central government is corrupt and divided.

In congressional hearings, Petraeus encountered all three U.S. senators campaigning to become the next commander in chief: Republican John McCain, a supporter of the war, and Democrats Hillary Clinton and Barack Obama, both of whom pledge to end the war as quickly as possible. One will inherit President Bush's costly blunder.

But Petraeus offered the view that it's too soon to talk about bringing more soldiers home. He recommended a delay in further troop withdrawals, beyond those scheduled to occur in July.

That's just fine with McCain, who claims that "success is within reach" in Iraq. But McCain used yesterday's hearings to tone down his hawkish rhetoric that he would keep American troops there for 100 years, if necessary.

Now, McCain thinks it's possible that the United States could bring home its troops "perhaps sooner than many imagine."

Sooner than even McCain imagined a few weeks ago, when his 100-year comment drew widespread ridicule.

Petraeus has done an admirable job in an extremely difficult situation. The surge of troops that began in January 2007 has helped to reduce the number of attacks. But the long-range picture in Iraq is no less bleak.

It's understandable for a commander in the field to want the flexibility to send troops home only when conditions warrant it. But Petraeus couldn't explain yesterday what those favorable conditions would be.

As Sen. Evan Bayh (D., Ind.) tried to paraphrase for the general: We'll know it when we see it, but we don't know when we'll see it. Unfortunately, President Bush has done a poor job of defining what it is.

The administration also hasn't explained what Americans have to gain from the further expense of troops' lives and tax dollars.

Bush is running out of time to ask for more time in Iraq. The administration should be setting a schedule to withdraw troops, subject to conditions on the ground. A stable government in Iraq looks increasingly like an unachievable goal. U.S. troops shouldn't be kept in harm's way indefinitely in these circumstances.

Sen. Joseph Biden Jr. (D., Del.) offered perhaps the most useful analogy of the day. He pointed out that the success of the troop surge has lowered the violence in Iraq only to the same level it was in 2005. "We cannot tread water forever," Biden told Petraeus.

The next president can't wait for what may never happen to get U.S. forces out of these treacherous waters.