The WaPo has this Robt. Kaiser article

The well-advertised differences between John McCain and Barack Obama on the war in Iraq may obscure a consequential similarity between their hawkish views on the use of American military force in other places.

Just two questions in the three debates between the two nominees touched on the subject, and neither has spoken at length on it during a fall campaign dominated by economic issues. Yet both have revealed a willingness to commit U.S. forces overseas for both strategic and humanitarian purposes. Both agree on a course of action in Afghanistan that could lead to a long-term commitment of American soldiers without a clear statement of how long they might remain or what conditions would lead to their withdrawal.

Both candidates favor expanding the armed forces, Obama by 92,000 and McCain by as many as 150,000. Both speak of situations when the United States might have to commit its troops for “moral” reasons, whether or not a vital American interest was at risk. Both accept what Andrew Bacevich, a retired Army colonel and professor at Boston University, calls the “unspoken consensus which commits the United States to permanent military primacy” — shared, Bacevich said, by leading figures in both parties

Neither candidate has spoken explicitly about how American and NATO forces would get out of Afghanistan.