For those of us on the left, the best argument in favor of the Afghan war is not Obama's claim that we need to stop Al Qaeda from returning to its bases in Afghanistan. Al Qaeda doesn't need to be in Afghanistan, the 9-11 plot was hatched by Saudis in Hamburg and Miami, and they can relocate to Somalia or Yemen or someplace else if they need to. (They have already relocated to Pakistan.)
The best argument is that we have an obligation to the Afghan people – especially to the feminists, secular teachers, labor organizers, health workers, democrats, all those working to build a secular, civil society. We encouraged them to help create a real alternative to religious fundamentalism. It would be wrong now to abandon them to the Taliban.
That argument is made by Michael Walzer at the Dissent magazine website,  where he writes that "a version of democratic politics has emerged" in Afghanistan -- "radically incomplete but valuable still. And all the people involved in these different activities would be at risk--at risk for their lives--if the United States simply withdrew."
That is an argument that Obama did not make.
If we accept the argument that we have incurred an obligation to protect democratic activists in Afghanistan, what exactly do we owe them? First of all, we owe it to them not to support an undemocratic government there. The Karzai government exists only because the US created and sustained it, despite massive election fraud, monumental corruption, and myriad failures to win popular support.
If we accept the obligations argument, we also owe it to the Afghans to fight a different kind of war – to stop attacking and killing large numbers of civilians. The way we have been fighting the war creates more enemies than are killed. Walzer is hopeful that Obama has "replaced the people who did everything wrong with people who are trying to do everything right." That means the US military must "stop killing civilians, work locally, disown corrupt officials, emphasize social and economic reconstruction." They have not been doing this for nine years, partly because that kind of careful, close-in fighting creates more American casualties than bombing suspected enemy locations.
And this commitment to Afghan democrats is not going to end in July 2010; it is open-ended. As long as the Afghan army and police are unable to protect teachers, feminists, health care workers, etc., we seem to have obligation to protect them – for as long as the Taliban fights to create their own Islamic state.
So: we owe it to the Afghans to support a democratic government, to fight a different kind of war, and for an indefinite number of years.
"One of the key criteria of a just war," Walzer writes, "is that there be a realistic possibility of achieving a just peace." He knows that "it may be too late" for that. But we need to ask: Is there a realistic possibility the US will abandon Karzai in favor of a democratic government? that the US military will fight the right kind of war? That the American people will be willing to keep paying for this war for many more years? What's wrong with the obligations argument is that the answer to each of these questions is "no."