During the nearly 15 years since the United States went to war in Afghanistan, the number of American troops there spiraled to 100,000, then dropped slightly below 10,000. President Barack Obama had planned to drop the number to 5,500 by the end of this year. Now he has decided to leave about 8,400 through the end of his presidency.
A timeline of the U.S. military presence in Afghanistan:
Oct. 7, 2001: President George W. Bush announces that U.S. and British troops have begun striking Afghanistan for harboring the al-Qaida terrorists blamed for the Sept. 11 attacks. The massive air campaign initially targets Taliban troops, training camps and air defenses.
November 2001: 1,300 American troops are in the country as commandos and ground troops, mostly Marines, begin to arrive.
December 2001: The U.S. force grows to 2,500 as troops scour the mountainous Tora Bora region looking for al-Qaida leader Osama bin Laden. The Taliban is ousted and an interim Afghan government is established.
March 2002: 7,200 U.S. troops are in Afghanistan as Americans lead allied Afghan forces in the largest ground assault of the war to date.
December 2002: The U.S. ends the year with about 9,700 troops deployed, mostly going after Taliban insurgents.
December 2003: The year ends with about 13,100 troops in Afghanistan.
April 2004: The number swells to 20,300 as the U.S. builds up forces along the Afghan-Pakistani border and provides security for fledgling reconstruction projects.
December 2006: Attention has shifted to the escalating war in Iraq; the force in Afghanistan remains just over 20,000.
December 2007: The force in Afghanistan rises to 25,000. Still, Iraq is the priority.
May 2009: As fighting in Afghanistan becomes more intense, the number of U.S. troops surpasses 50,000.
December 2009: Troops now number more than 67,000, and the situation is deteriorating, with escalating violence and more service members killed. Obama orders in another 33,000 troops to battle al-Qaida militants and a resurgent Taliban.
August 2010: The U.S. force reaches 100,000.
May 2011: Bin Laden is found hiding in neighboring Pakistan and killed in a U.S. special operations raid. There are still about 100,000 troops in Afghanistan.
June 2011: Saying the U.S. is meeting its goals in Afghanistan, Obama announces his withdrawal plan: Bring home 10,000 troops by the end of 2011, and continue at a steady pace until handing over security responsibilities to the Afghans by 2014.
September 2012: Troop levels down to 77,000.
December 2013: Down to 46,000 troops, the slow withdrawal continues.
March 2014: With nearly 34,000 troops in Afghanistan, Obama orders the Pentagon to develop options for a complete military withdrawal, because Afghan President Hamid Karzai refuses to sign a security agreement with the United States.
May 2014: Obama announces his plan to pull virtually all U.S. troops out of Afghanistan by the end of 2016, when his second term in office will be drawing to a close.
December 2014: Troop levels have been cut in half since Obama's announcement in May, down to 16,100. Obama declares their combat mission over, but troops will continue training and advising Afghan forces.
March 2015: Troops decline to their current number — about 9,800 — on track for a nearly total withdrawal in 2016.
Oct. 15, 2015: In a reversal, Obama says the situation is too fragile for the American military to leave. He announces plans to keep the current force of about 9,800 in place through most of 2016 to continue counterterrorism missions and advise Afghans battling a resurgent Taliban. The plan is for the number to decrease to about 5,500 troops by December 2016.
July 6, 2016: Saying the security situation in Afghanistan "remains precarious," Obama announces that instead of dropping the U.S. troop level to 5,500, he will keep it at about 8,400 through the end of his term on Jan. 20, 2017. He said his successor can determine the next move.
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