Vice President Dick Cheney argued forcefully Tuesday against an early withdrawal of US forces from Iraq, saying that would be "unwise in the extreme" and increase the risk of terrorist attacks in the United States and other nations. Cheney told military troops that terrorists can win in Iraq only "if we lose our nerve and abandon our mission." He rejected calls for a speedy drawdown of troops. With snow falling outside, Cheney spoke in a cavernous aviation hangar on this base in northern New York, addressing an audience that base officials put at around 3,000. It was the latest installment in the administration's effort to shore up slumping support for the war with a series of speeches ahead of Dec. 15 elections to pick a permanent Iraqi government.