I don’t think there’s a bigger campaign promise that Barack Obama made than getting troops out of Iraq. His opposition to the war is the reason he won the nomination; I don’t even think that’s a controversial statement. And of the many advances he’s touted in his first week as a candidate for re-election, there hasn’t been a bigger one that getting our troops out of Iraq. The final phase of that process is scheduled for the end of 2011, a year before the election.

Or is it? Speaking in Iraq today, Defense Secretary Robert Gates hinted that US troops could stay longer.

US troops could if required by Iraq stay in the country beyond the agreed withdrawal date of 31 December, 2011, the US defence secretary has said.

Robert Gates, who is visiting Iraq, says an extended military presence is an option.

“If folks here are going to want us to have a presence, we’re going to need to get on with it pretty quickly in terms of our planning,” he said.

This would be taken as a final betrayal, I believe, in the eyes of many of President Obama’s supporters. There are a couple big issues to the Democratic base that will not be able to be overcome: a sellout on retirement security and a broken promise on Iraq.

However, it’s not quite that simple. Notice Gates’ words. He says that the US needs clarity quickly if “folks here are going to want us to have a presence.” In fact, under the terms of the status of forces agreement, Iraq would have to ask for an extended presence of ground troops for the US to grant it. Now there’s probably some pressure from the White House to get Iraq to make that ask. Unrest as part of the Arab uprising and concerns about tensions in Kirkuk, as well as the general inertia around issues of war and the fact that the American empire never leaves without being pushed, probably are weighing on the White House. Recently US forces went into Kirkuk unilaterally, which is outside the bounds of the SOFA. I’ve heard rumors that Obama doesn’t want to have “lost Iraq,” and is trying to come up with a back-up plan.

But if there’s a concern that a full drawdown of US forces could lead to sectarian violence, allowing forces to stay could very easily lead to the overthrow of the government. Prime Minister Nouri al-Maliki would have a very tenuous hold on power if he allowed some US forces to stay, either in Kirkuk or throughout Iraq. His coalition includes the Sadrists, who would almost certainly bolt the coalition in that event. Muqtada al-Sadr firmly opposes any US presence on Iraqi soil, and has reiterated that in recent days. Aside from Maliki wondering about his own political career, both countries would have to be concerned about the destabilizing event of a government collapse years before the next election was supposed to take place.

Gates wants Iraq to decide quickly, which kind of tells you where he and the US want to go – with a continuing presence. In fact, Gates said it himself. “I think there is interest in having a continuing presence, but the politics are such that we’ll just have to wait and see because the initiative ultimately has to come from the Iraqis.” And the artificial deadline is meant to up the pressure.

But Maliki is highly unlikely to threaten his own hold on power. In a statement, Maliki said he replied to Gates by saying that “our armed forces in the military and police have the power to confront any attack, and their capabilities to impose security and stability increase day by day.” But between the lines, this isn’t about security capabilities, it’s about politics. And Maliki has some serious competing pressures here.

UPDATE: Video of the Gates Q&A: