Republican presidential candidate Rudy Giuliani on Tuesday accused former President Bill Clinton of not responding forcefully enough to the 1993 World Trade Center bombing or later terrorist attacks. The former New York mayor criticized Democrats, accusing them of weakness and naivete in dealing with terrorism. Giuliani made the comments to about 650 business, corporate and political leaders at Regent University, the conservative Christian college founded by religious broadcaster Pat Robertson. "Islamic terrorists killed more than 500 Americans before Sept. 11. Many people think the first attack on America was on Sept. 11, 2001. It was not. It was in 1993," said the former New York mayor.