U.S. Senator John McCain, R-Ariz., right, answers a question at a press availability after a session on Afghanistan at the Halifax International Security Forum in Halifax, Nova Scotia on Saturday Nov. 21, 2009. Rick Hillier, left, former chief of Canada's defence staff, listens. (AP Photo/The Canadian Press, Andrew Vaughan)

U.S. Senator John McCain, R-Ariz., answers a question on Afghanistan at the Halifax International Security Forum in Halifax, Nova Scotia on Saturday Nov. 21, 2009. (AP Photo/The Canadian Press, Andrew Vaughan)

U.S. Senator John McCain, R-Ariz., answers a question at a press availability after a session on Afghanistan at the Halifax International Security Forum in Halifax, Nova Scotia on Saturday Nov. 21, 2009. (AP Photo/The Canadian Press, Andrew Vaughan)

US Senator John McCain speaks to members of the press at the Halifax International Security Forum in Halifax, Nova Scotia, November 21, 2009. REUTERS/Jeff Harper (CANADA POLITICS)

US Senator John McCain speaks to members of the press at the Halifax International Security Forum in Halifax, Nova Scotia, November 21, 2009. REUTERS/Jeff Harper (CANADA POLITICS)

General (Retired) Rick Hillier (L) listens as US Senator John McCain speaks to members of the press at the Halifax International Security Forum in Halifax, Nova Scotia, November 21, 2009. REUTERS/Jeff Harper (CANADA POLITICS)

Sen. John McCain, R-Ariz., pauses in the Capitol in Washington, Wednesday, Nov. 18, 2009.(AP Photo/Alex Brandon)

US Sen. John McCain waits to be introduced prior to delivering remarks at the John Hopkins University Paul H. Nitze School of Advanced International Studies (SAIS) November 9 in Washington, DC. McCain predicted an allied win in Afghanistan in one year to 18 months if sufficient troops are sent, as the White House mulls sending tens of thousands of reinforcements.(AFP/Getty Images/File/Alex Wong)

U.S. Sen. John McCain speaks at the Wall Street Journal CEO Council meeting on rebuilding global prosperity in Washington, November 17, 2009. REUTERS/Larry Downing (UNITED STATES POLITICS BUSINESS HEADSHOT)

U.S. Sen. John McCain speaks at the Wall Street Journal CEO Council meeting on rebuilding global prosperity in Washington, November 17, 2009. REUTERS/Larry Downing (UNITED STATES POLITICS BUSINESS HEADSHOT)

Despite fierce public pressure to end the war in Afghanistan eight years on, politicians and experts decried calls for setting an exit date they say would embolden the Taliban. "History shows us that if you set dates for when you're going to leave, the enemy waits until you leave," US Senator John McCain said at the Halifax International Defense Forum in easternmost Canada.(AFP/File/Mandel Ngan)