Bob is a corporate executive lving in freedonia who is alleged to have defradued stockholders to the tune of 20,000,000. however the government cannot prove that bob knew that any information he made public was false and so bob cannot be tried in court for his actions. Outraged, freedonia passes a law that states, "we hereby declare that bob defrauded stockholders of his company and we order bob to repay 20,000,00 to his company's stockholders. What is bob's best ground on which to fight the legislative action?