Throughout the campaign, Barack Obama vowed that one of his first actions as president would be to issue a new order to military to end the war in Iraq. Since his resounding electoral victory, however, there has been a quiet campaign among the foreign-policy establishment and parts of the military to roll back those promises. This would be a mistake. The argument for a significant, early withdrawal of U.S. combat forces remains overwhelming. Indeed, a failure to deliver on the promise of early U.S. withdrawals is the most likely thing to cause a rapid deterioration in conditions in Iraq.

Those who warn that security gains in Iraq are fragile and reversible are correct, even if they argued the contrary before the election. We should be under no illusions that Iraq will be stable or peaceful, or that its political divides have been overcome. As Brian Katulis of the Center for American Progress and I argued in September, beneath the superficial veneer of improved security upon which most Americans have focused, Iraq continues to be torn apart by deep divides over ethnicity and religion and by escalating battles between political insiders and popular forces. Despite some promising developments, little political reconciliation has taken place since the "surge" began.

There are some promising developments, and great hopes that the fragile security gains will hold and that the coming rounds of elections will produce a more stable Iraqi political order. But we should not count on best case scenarios coming to pass. It is absolutely essential for the administration to be prepared for a series of challenges that will likely arise. It should anticipate these contingencies and be prepared to respond appropriately, so that they are less likely to disrupt withdrawal plans and destabilize Iraq. To that end, this memo lays out a series of likely challenges in the first six months after the inauguration and a number of plausible contingencies for which the United States must be prepared. It then makes the case for the need to stick to a withdrawal schedule in line with the one presented by President-elect Obama during the campaign -- one that does not contradict the Status of Forces Agreement (SOFA), is not irresponsible, and does not threaten Iraq's fragile gains. The new administration will get only one chance to demonstrate the credibility of its commitments, and indefinitely leaving troops at current levels will only postpone rather than solve the problems.

Part I: Implementing the SOFA

Implementing the SOFA (which Iraqis tellingly call the "Withdrawal Agreement") will be the overwhelming priority in U.S.-Iraqi relations over the coming six months, leading up to the all-important referendum on its ratification scheduled for July 31. Iraqis will be watching carefully to see whether the United States honors its commitments, and will likely test the limits of the agreement. Elements within the U.S. military will also likely wish to test those limits, judging by comments made by Gen. Raymond Odierno, the top U.S. commander in Iraq, and others.

Iraqis (and many Americans) are perplexed at the president-elect's real intentions. Addressing these concerns head-on and publicly early in the administration is crucial. The new administration should do everything it can to adhere to the SOFA/WA and to build support inside of Iraq ahead of the referendum. This should not be problematic, since there is no contradiction between Obama's timetable and that of the SOFA/WA. Clarity and consistency is key. He should say clearly that all combat troops could be withdrawn within 16 months, as promised, while the residual force envisioned in the campaign platform could then legally remain in Iraq to carry out training and counter-terrorism functions through the end of 2011, at which point their role could be jointly negotiated with the Iraqi government.

Among the major challenges likely to arise:

• Troops return to bases (June 30). The first major deadline in the SOFA/WA will pose a significant challenge. The requirement that U.S. troops return to their bases contradicts core elements of U.S. counterinsurgency doctrine, and would represent a significant change to operations particularly in the cities. U.S. military officials have suggested that little will change in practice, but Iraqis clearly expect that they will. Managing the perceptions and the operational realities of this new legal situation will be a serious challenge -- particularly given the proximity to the SOFA/WA referendum.
• Detainee release. Also related to the SOFA is the question of detainee release, a major Iraqi (and particularly Sunni) demand. But if some 10,000-15,000 detainees rapidly return to their communities, violence and instability could follow. Slow-rolling the detainee releases, on the other hand, could undermine support for the SOFA referendum and trigger a legal challenge, while transferring large numbers of detainees to an Iraqi system seen as sectarian could spark sectarian tensions.
• Referendum (July 31). This referendum will hang over all Iraqi politics and U.S.-Iraqi relations for the first half-year of the administration. Should the SOFA/WA fail to pass, U.S. forces will need either to begin withdrawing at an uncomfortably rapid rate or else find some other formal authorization to remain. Neither will be an attractive proposition. The government wants the agreement to pass, and will likely establish rules and a format conducive to success. But opposition forces will attempt to mobilize outrage at every opportunity to portray the United States as violating the terms of the SOFA/WA and not actually intending to withdraw. The referendum will almost certainly become a major issue in intra-Shia (and to a lesser extent intra-Sunni) political competition. U.S. policy needs to be extremely careful to not feed these flames.