Even last week’s swearing in of Ryan Crocker -- one of the most talented U.S. diplomats -- as ambassador to Kabul seems unable to stanch the perception that U.S. efforts in Afghanistan are waning. Most Americans take solace in the notion that, in President Barack Obama’s words, “the tide of wars is receding,” regardless of whether the administration can tie its disengagement to success.

But for Afghans and others in the region, Obama’s decision in June to start bringing U.S. forces home, beginning with a withdrawal of all 33,000 surge troops by September 2012, is the start of a post-American Afghanistan that is certain to be marked by regional competition and more battles with extremism. Is there any way to recapture momentum in Afghanistan?

Fortunately, the answer is yes. But it will require a bold move by Obama. For months, the administration has been working with the Afghans on a new strategic partnership. This initiative seeks to make the point that U.S. support for Afghanistan will continue, even if military forces are exiting. The likely centerpiece of the partnership -- civilian assistance to the private sector, educational institutions and scientific endeavors -- is important. But it will seem fanciful against the backdrop of the competition among parties that will rush to fill the power vacuum when the U.S. military leaves.

Instead of focusing the strategic partnership solely on civilian cooperation, the U.S. and Afghan governments should declare their intention to negotiate a Status of Forces Agreement by early 2012. A SOFA is a bilateral agreement that regulates the legal status of armed forces while they are in a host country. The U.S. has more than 110 SOFAs or similar arrangements around the world.

Unusual Framework

U.S. forces are in Afghanistan under an unusual legal framework. Their legality rests upon a combination of a United Nations Security Council resolution, a related Military Technical Agreement with the Afghan government, and an exchange of letters between the U.S. and Afghan governments that took effect in May 2003. A U.S.-Afghan SOFA would formalize the arrangements in those letters.

More importantly, a SOFA could be key to an outcome in Afghanistan that is sustainable, protects core U.S. interests, and is good for Afghans and the region. For most of the current U.S. engagement with Afghanistan, the U.S. believed this result could be achieved only through the construction of a strong, democratic Afghan state along the lines of the current constitution, which envisions a relatively robust presidency and central government. (Indeed, Obama’s June 22 speech explicitly spoke of an outcome consistent with the present constitution.)

This sort of state was seen as essential to minimize the power of warlords, who tore apart the country and inflicted grave crimes against Afghans in the 1990s. Under the outcome the U.S. has been pursuing, the Taliban would be able to participate in the political process, but only under the existing political system. This scenario is no longer realistic.

For one thing, building the national institutions necessary for this kind of government in Afghanistan requires far more time and money than are available for the task today. And to get the Taliban to enter the political process on the current terms would require weakening the group further through much greater, more sustained success on the battlefield. It would also require Pakistan to lean on the Taliban more heavily than it has shown a willingness to do in a decade.

Another acceptable outcome is still feasible, if not easily achieved. This outcome would involve a new political compact, negotiated among a broad set of groups in Afghan society, and resulting in a new configuration of the state. This new order would almost surely involve greater decentralization or federalism and enable provinces or districts significant latitude in managing their own affairs.

Such an arrangement would at the same time increase the chances of conflict and appeal to different political groups, including the Taliban, by creating more space for them in the system and more latitude for different styles of governance. To mitigate the risks, a new constitution would need to maintain a central government with limited but meaningful powers. And there would need to be mechanisms to hold the regional governments accountable to prevent a devolution to the warlordism of the 1990s.

Diplomatic Effort

Accomplishing this outcome would still require a major diplomatic effort involving Afghanistan’s neighbors and a broad cross section of Afghanistan’s groups. It would take months or even years to produce. And it would require that the U.S. be an effective facilitator, participant and likely guarantor of an agreement.

Unfortunately, the current perception that the U.S. is disengaging from Afghanistan regardless of the situation on the ground undermines the ability of the U.S. to play these roles. Any U.S. effort to produce a negotiated outcome today will be seen as an alternative to withdrawal with no political compact - - but not an alternative to withdrawal.

A SOFA could change this perception instantly. Its very existence signals the intention to keep at least a small number of U.S. forces in Afghanistan for the long term, even if it does not commit to any particular troop level. It would be a strong signal that the U.S. has a long-term commitment to the region and, therefore, would create needed leverage in negotiations. It would be a strike against those who would simply prefer to wait out the U.S. A SOFA would weaken those in the Pakistani military who argue that Pakistan should not pressure the Afghan Taliban as they are likely -- with the Americans gone -- to be back in power in a few years.

A SOFA could also increase the prospects of Afghan success in other, more indirect ways. One of the major obstacles to building an Afghan state today is the predatory behavior of many Afghans. Because they do not believe the state will long outlast U.S. involvement in the country, they are more inclined to seek immediate gain (through bribery, corruption or theft) than to make hard decisions to support the government when those actions will bear fruit only over the long run. A credible, long-term commitment to Afghanistan by the U.S. may help shift this calculation.

Reset Relations

Similarly, a SOFA could provide the impetus for a badly needed reset of relations with the government of President Hamid Karzai. The Obama administration missed the opportunity to leverage the December 2009 surge to get Karzai to take tough steps on corruption. Negotiating a SOFA could provide a second opportunity. Although some say Karzai might resist a SOFA, it could actually strengthen him if it were negotiated to address issues of sovereignty, such as civilian casualties, that are a thorn in the sides of Afghans. The inclusion of similar issues in the negotiation of an Iraqi SOFA in 2008 was crucial to Iraqi ownership of the agreement.

Achieving a SOFA would not be without difficulties. Iran would undoubtedly oppose any legal mechanism to keep U.S. troops on neighboring soil. The Taliban would tout the occupation narrative. Obama would need to manage the domestic politics. Still, such an agreement does not suggest large numbers of troops will be in Afghanistan indefinitely. The U.S. has SOFAs with countries hosting only a few hundred troops. Fortunately, a SOFA is not a treaty and does not need congressional approval.

The U.S. has already announced its intention to scale back the means devoted to the Afghan mission, but has not yet come to terms with the redefinition of the ends, which must follow. A less centralized solution is short of what Americans originally wanted for Afghanistan, given the risks of a return to fiefdoms and the reign of warlords. But it can still uphold U.S. and Afghan interests. Although a U.S.-Afghan SOFA does not solve all problems, it provides the surest and most effective way to reposition the U.S. if it is to midwife -- and then protect -- such an outcome.

(Meghan O’Sullivan is a Bloomberg View columnist. The opinions expressed are her own.)

To contact the writer of this article: Meghan O’Sullivan at Meghan_OSullivan@hks.harvard.edu.

To contact the editor responsible for this article: Lisa Beyer at lbeyer3@bloomberg.net.