Iraq’s prime minister just did Barack Obama a huge favor.

By finally approving a status-of-forces agreement, or SOFA, that requires a U.S. pullout by the end of 2011, Nouri al-Maliki has saved our president-elect from facing a huge Iraq crisis from the day he’s sworn in. (The accord still must be approved by the Iraqi parliament on Monday, but that now seems very likely.)

And by accepting a fixed withdrawal deadline (after rejecting this concept for years), President Bush also has made Obama’s life easier. Now no one can blame Obama for the fixed 2011 deadline.

The agreement has the additional benefit of giving Obama more flexibility than his campaign promise to withdraw all troops in 16 months.

The 16-month pledge had locked Obama into a time frame that was too hasty (even though he hinted he might modify it). Iraq’s security situation is still too fragile to be managed by its own security forces that soon without U.S. assistance. And the country needs additional protection for provincial and national elections next year.

So the 16-month pledge was hanging like an albatross around the president-elect’s neck. Our next leader faced the prospect of being labeled by history as the man who “lost Iraq” if a too-speedy U.S. exit led to an implosion there.

As if that prospect weren’t sufficiently daunting, Obama might have had to pull out U.S. troops even more quickly. That’s because, until this week, al-Maliki was refusing to submit the SOFA for cabinet and parliamentary approval until he got further changes in language. But the U.N. mandate under which U.S. troops in Iraq operate was set to expire on Dec. 31. Had SOFA negotiations dragged on much longer, U.S. troops might have been left with no legal mandate as the Bush administration was expiring.

Iraq would have been forced to seek a short extension of the U.N. mandate as a stopgap measure. Obama would have confronted a huge mess in Iraq from the day he took the oath.

Iraqi politicians, facing national elections, would have been even more reluctant to sign a SOFA after January. (In private, almost all Iraqi factions agree that U.S. troops are needed for some time; in public, they are wary of taking positions that offend nationalist pride.) With no agreement in place, Obama’s Democratic base would have pressed for the swiftest possible withdrawal.

Al-Maliki’s decision has saved Obama from being caught in a crossfire between Iraqi politicians and MoveOn.org.

Assuming it passes, the agreement also gives Obama the flexibility to revise his withdrawal schedule.

Although the accord’s 2011 deadline doesn’t preclude a swifter pullback, there is little sign that that would be possible without precipitating a return of sectarian violence. The 2011 target permits Obama to deflect pressure from his base for a swifter exit, while adjusting the pace to fit ground conditions.

At the same time, during a time of great economic crisis, it reassures worried Americans that a withdrawal is within sight.

The SOFA’s requirement that all U.S. troops pull back to bases from Iraqi cities by June will sorely test Iraqi forces and could lead to renewed sectarian violence. The three-year timeline for total withdrawal at least gives Obama some room for maneuvering during the initial stages. It also gives him time to initiate the regional diplomacy needed to stabilize Iraq in the long term.

Iraqis will still have the option of requesting an extension after 2011. This would not contradict Obama’s vision of leaving some U.S. forces in Iraq for training and support beyond that date.

Indeed, given the extraordinary complexity of the Iraq problem, the agreement represents the best possible outcome.

Iraqi life is still harsh and brutal, and violence is far from over. The Iraqi government is corrupt, and its political institutions are still weak.

Yet things have improved to the point where Iraqis want to exert their sovereignty.

“Every day, the influence of America is getting less,” one Iraqi politician told me, “and the influence of Iraqi politics more and more.”

That is how it should be. Let’s hope the status-of-forces agreement is finalized next week.