U.S. and Coalition Military Operations in Afghanistan: Issues for Congress [Updated December 11, 2006] [open pdf - 127KB]
From the Summary: "The U.S. military has been involved in Afghanistan since the fall of 2001 when Operation Enduring Freedom toppled the Taliban regime and attacked the Al Qaeda terrorist network hosted by the Taliban. A significant U.S. military presence in the country could continue for many years as U.S., North Atlantic Treaty Organization (NATO), Coalition, and Afghan National Army (ANA) forces attempt to stabilize the country by defeating the insurgency, facilitating reconstruction, and combating Afghanistan's illegal drug trade. Despite NATO's assumption of command of the International Security Assistance Force (ISAF), the United States will remain the largest troop contributing nation and will continue Operation Enduring Freedom, intended to locate and destroy insurgents and terrorists operating in Afghanistan. Recent NATO combat operations have resulted in a request for an additional 2,000 to 2,500 NATO troops as well as a call for NATO nations to rescind national caveats on how their forces may be employed in Afghanistan. Insurgent activity continues to evolve, with some of the tactics and techniques being used by Afghan insurgents reportedly similar to those employed in Iraq. Reports suggest that instead of building a 70,000 soldier Afghan National Army as agreed to in the 2002 Bonn Conference, the Administration intends to support a 50,000 soldier force, while some Afghan officials suggest that a 150,000 man Afghan National Army will be needed to insure both internal and external security. Senior U.S. officials have also stated that the Afghan National Army needs to be significantly better equipped if it is to become an effective security force."
CRS Report for Congress, RL33503