Our NATO allies have to shoulder a bigger burden, and we should continue to seek more combat troops with fewer restrictions. Jawboning reluctant allies has its limits; we will need to persuade countries unwilling to take on expanded combat roles to contribute more toward other aspects of the mission, including development and police training.

Afghanistan is not Iraq, and we should not expect the same results from a troop increase as occurred in Iraq. There, a broad Sunni tribal awakening was crucial. In Afghanistan, decades of war have weakened tribal structures, and the Taliban — unlike the brutal foreigners who comprise al-Qaeda in Iraq — have deep roots in Pashtun society. More troops, however, can create the conditions for enhanced reconstruction efforts and increase our leverage for the political solution sought by Gen. David Petraeus.