President Obama is expected to announce on Tuesday a substantial escalation of the U.S. mission in Afghanistan: more training for the Afghan army, more support for Afghan governance and tens of thousands more American troops.
It is a difficult choice but also the right one. While there is no guarantee that the new measures will reverse what is now a losing effort, the alternatives under consideration - from a more limited counterterrorism strategy to maintaining the current force - have been tried and have failed. While sending more Americans to war will entail a painful cost in lives, abandoning Afghanistan to civil war or rule by the Taliban would be immoral - and would endanger key American interests.
Obama's prolonged deliberations and some of his public comments have made clear that he will embark on this new course reluctantly. That is understandable, given the problems in Afghanistan and the lack of Democratic support for an expanded war.
Yet once he has chosen his strategy, it's vital that the president commit himself fully to its success. That requires sending enough troops to reverse the Taliban's momentum and describing the new commitment in a way that will convince Afghans, allies, the Taliban and the leaders of neighboring Pakistan that the United States is determined to succeed. It also means avoiding hedges and conditions that could doom the escalation before it begins.
One of Obama's dilemmas this week will be the need to address multiple audiences with competing interests, from dovish House Democrats to suspicious Pakistani generals. The president has already been aiming reassurances at his domestic audience, such as his promise last week to "finish the job" in Afghanistan - and his spokesman's declaration that "we're not going to be there another eight or nine years." But the most important messages will be those received in the war zone.
Experts concur that a large majority of Afghans do not wish to see a resurgence of the Taliban but that many will be inclined to support the side that they believe is most likely to prevail. Pakistan's military commanders, too, will carefully measure U.S. resolve before deciding to break irrevocably with the Afghan Taliban leaders based in their country. If the new American strategy is cluttered with "exit ramps" or closely linked to timetables, the effect of the additional troops will be undermined.
The Afghan government and President Hamid Karzai also require careful handling. Success will require better performance by Mr. Karzai, and the Western alliance will want to be creative in building up local governments and forging informal alliances with towns and tribes.
But publicly disparaging Karzai or holding out the abandonment of his government as an option is likely to ensure that he clings to the warlords he should break with or seeks out other foreign sponsors. Though support for the Afghan government cannot be unbounded, a plan that counts on turning over the war to a large Afghan army won't work unless a way is found to nurture and work effectively with the political leadership in Kabul.
As Obama has deliberated, much of what has been said or leaked by his administration has concerned why the war might be unwinnable. Karzai's failings have been thoroughly aired, along with Afghanistan's long history of swallowing foreign armies; there have been discussions of the high cost of more troops and of doubts about whether the Taliban really threatens the United States.
If he now is to propose going forward with a campaign to defeat the Taliban and stabilize the country, Obama needs to make the case strongly for why it is needed and how it can work. Both Americans and Afghans wonder whether the president believes in the war and has the will to win it. Among his challenges Tuesday will be to put those doubts to rest.