Angry boos greeted Sen. Hillary Rodham Clinton (D-N.Y.) at a liberal conference yesterday when she opposed fixing a date for withdrawing American forces from Iraq. The sour audience response, at the Campaign for America’s Future conference, hints at the 2008 presidential front-runner’s shaky standing with anti-war Democrats, who wield increasing power in the party. Clinton’s speech packed the room with a crowd billed as the nation’s largest gathering of progressives. But, although the left-leaning audience raucously cheered her domestic agenda, there was only a sprinkling of applause mixed with jeers when the senator refused to disavow her vote authorizing the...