"Stated U.S. policy is to ensure that Afghanistan will not again become a base for terrorist attacks against the United States. Following policy reviews in 2009, the Obama Administration asserted that it was pursuing a well-resourced and integrated military-civilian strategy intended to pave the way for a gradual transition to Afghan leadership that will begin in July 2011 and be completed by the end of 2014. To carry out U.S. policy, a total of 51,000 additional U.S. forces were authorized by the two 2009 reviews, bringing U.S. troop numbers to their current level of about 99,000, with partner forces adding about 42,000. On June 22, 2011, President Obama announced that the policy had accomplished most major U.S. goals and that a drawdown of 33,000 U.S. troops would take place by September 2012. The first 10,000 of these are to be withdrawn by the end of 2011, of which 5,000 will return home in July 2011 in concert with the start of a longplanned transition to Afghan security leadership. That transition will start in four cities and three full provinces. Amid widespread doubts that Afghan governance and security institutions will be strong enough to protect themselves by that time, U.S. officials say that the U.S. intent is for a long-term relationship with Afghanistan that might include U.S. military involvement long after 2014."
CRS Report for Congress, RL30588