"Afghan security forces have lead security responsibility throughout the country, and the United States and its partner countries are in the process of winding down the current international security mission by the end of 2014. A planned post-2014 mission will consist mostly of training the Afghanistan National Security Forces (ANSF). The number of U.S. forces in Afghanistan, which peaked at about 100,000 in June 2011, was reduced to a 'pre-surge' level of about 66,000 by September 2012, and to about 34,000 as of February 2014. The U.S. force will be about 28,000 as of June 1 and will decline further to 22,000 by the end of October. President Obama announced in late May 2014 that the follow-on mission will include 9,800 U.S. forces, declining in the beginning of 2015 to 4,900 mostly in Kabul and at Bagram Airfield, before winding down to a small force (about 1,000) after 2016, engaged mostly in handling military sales to Afghanistan. The post-2014 force is contingent on Afghanistan's signing a Bilateral Security Agreement (BSA) with the United States. All the candidates in the April 5, 2014, presidential election--which took place with apparent high turnout and minimal violence--publicly support the agreement. A successor will take office in late July or August--after votes from a June 14 runoff are certified. Fearing instability after 2014, some ethnic and political faction leaders are reviving their militia forces should the international drawdown lead to a major Taliban push to retake power."
CRS Report for Congress, RL30588