WASHINGTON — Democratic presidential candidate Barack Obama ridiculed Vice President Dick Cheney on Friday for saying Britain's decision to pull troops from Iraq is a good sign that fits with the strategy for stabilizing the country. Obama, speaking at a massive outdoor rally in Austin, Texas, said British Prime Minister Tony Blair's decision this week to withdraw 1,600 troops is a recognition that Iraq's problems can't be solved militarily. "Now if Tony Blair can understand that, than why can't George Bush and Dick Cheney understand that?" Obama asked thousands of supporters who gathered in the rain to hear him. "In...