Escaping the "graveyard of empires"

"Given the nature of the conflict in Afghanistan, a definitive, conventional victory is not a realistic option. Denying a sanctuary to terrorists who seek to attack the United States does not require Washington to pacify the entire country, eradicate its opium fields, or sustain a long-term military presence in Central Asia. From the sky, U.S. unmanned aerial vehicles can monitor villages, training camps, and insurgent compounds. On the ground, the United States can retain a small number of covert operatives for intelligence gathering and discrete operations against specific targets, as well as an additional small group of advisers to train Afghan police and military forces. The United States should withdraw most of its forces from Afghanistan within the next 12 to 18 months and treat al Qaeda's presence in the region as a chronic, but manageable problem."--Executive summary.