SANTA ANA, Calif., Sept 5 (Reuters) - Former President Clinton warned on Thursday that a U.S. attack on Iraq could prompt Saddam Hussein to use chemical or biological weapons against U.S. interests because he would have nothing to lose. Speaking to a group of Democratic Party supporters at a Santa Ana, California fund-raiser for Congresswoman Loretta Sanchez, Clinton said President Bush had to consider Saddam's reaction to an invasion before taking action. "Saddam Hussein is not a good man by our definition," Clinton said. "There's no question ... he has significant stocks of chemical and biological agents." "I think we...