President Barack Obama's drawdown to 50,000 U.S. troops has been well implemented and is, in fact, a prudent course of action. It is generally consistent with the thrust of his campaign promises. One could nitpick about whether it truly satisfies his pledge to have all combat units out of Iraq within 16 months of inauguration, as it has taken 19 months to get down to the 50,000 troops, which are roughly organized into five brigades.

HIGH ALERT: An Iraqi soldier hands out a leaflet calling on citizens to be attentive to militant activity at a checkpoint in central Baghdad on August 31 (XINHUA/AFP)

The fact that they have been re-designated as "advise and assist" brigades, rather than traditional combat units, matters little; they still carry enormous firepower. That firepower is, in part, what makes them so useful. In addition, the declaration that the U.S. mission is changing from a military combat operation to a non-combat, civilian-led operation is largely semantic. That transition has been gradual and does not mean the war is over.

For these reasons—and because the drawdown is possible largely due to the success of the troop surge implemented by General David Petraeus in 2007 and 2008—Obama should not make too much partisan hay out of his success.

But he, along with Vice President Joe Biden, has handled the challenge well since taking office, so in reality, the president does have some limited bragging rights. They have constructed and implemented a gradual troop reduction plan. They have also been careful to not only talk frequently with Iraqi political leaders of all types but to mostly do so behind the scenes. Thus far, this has been appropriate.

At present, though, it would be a mistake to call Iraq anything more than a provisional success. Things can still go wrong. Iraqis have made remarkable progress, both on the battlefield and, despite the ugliness of the process, with their politics. But there are major challenges ahead.

Sectarian wounds from one of the decade's worst civil wars have begun to heal, but can still be reopened. There are important unresolved territorial disputes, particularly among Arabs, Turkmen and Kurds in the north. There is ongoing violence and a residual, unrelenting extremist presence. The Sunni volunteers, known as the Sons of Iraq, are not yet adequately integrated into the Iraqi Government and economy and they could still be a force for evil, rather than good, in the country. The economy is still fairly weak.

Most of all, Iraqi politics are paralyzed. At present, there is a lame duck government, with no end in sight to the delays in trying to form a new government. As my colleague Ken Pollack argues, we should not yet be too alarmed by this fact, but we should be concerned.

As noted, in my view, Obama is right to reduce U.S. forces to 50,000. After all, U.S. troops already left Iraq's cities last June; they have been replaced in most situations by the 700,000-member Iraqi security force and are no longer needed in large numbers. Even though July and August have been somewhat bloodier than previous months this year, the general security situation in Iraq has not significantly deteriorated.

But removing all U.S. military units by the end of next year, as currently envisioned, is too fast. The calming, confidence-building role they play remains important and will probably stay that way. For example, they can accompany Iraqi army and Kurdish Peshmerga forces on joint patrols in the contested north, and they can help man checkpoints in that area as well, providing a reassuring role. There is little reason to expect that role to become unnecessary anytime soon.

The plan to withdraw all U.S troops over the next 16 months was negotiated between Iraq and former President George W. Bush and is a formal bilateral understanding. It must be formally renegotiated and revised before it can be replaced. Only a new Iraqi Government will have the legitimacy to do that.

So we have to wait. And in the coming weeks, Iraqis will have to find a way to end the political stalemate—even if that means Obama and Biden need to increase their roles. With regards to Iraq, the president has done a good job so far. But this may be only the beginning of the hard work.

The author is a senior fellow with the Washington, D.C.-based Brookings Institution

(Viewpoints in this article do not necessarily represent those of Beijing Review)