By SADAQAT JAN and ZARAR KHAN, Associated Press Writers 8 minutes ago RAWALPINDI, Pakistan - Pakistan opposition leader Benazir Bhutto was assassinated Thursday in a suicide attack that also killed at least 20 others at a campaign rally, aides said. ADVERTISEMENT The death of the 54-year-old charismatic former prime minister threw the campaign for the Jan. 8 parliamentary elections into chaos and created fears of mass protests and violence across the nuclear-armed nation, an important U.S. ally in the war on terrorism. The attacker struck just minutes after Bhutto addressed thousands of supporters in the garrison city of Rawalpindi, 8 miles south of Islamabad. She was shot in the neck and chest by the attacker, who then blew himself up, said Rehman Malik, Bhutto's security adviser. At least 20 others were killed in the attack. Bhutto was rushed to the hospital and taken into emergency surgery. "At 6:16 p.m., she expired," said Wasif Ali Khan, a member of Bhutto's part...