FAIRFIELD -- Using apocalyptic imagery of civilization lost, Sen. Joseph I. Lieberman blamed politics Friday for undermining the war on terror and leaving the U.S. vulnerable to "barbarians at our gates." The U.S. faces a patient and ruthless enemy in Islamic extremists, an enemy that "threatens not just America, but all of civilization," Lieberman said in a national security speech at Fairfield University. "We remain too divided as a nation, and in Washington, spend too much time fighting each other rather than coming together to make our country safer," Lieberman said. "At stake is the kind of world we will...