Early this month, the Illinois Supreme Court clarified the standard of proof governing retaliatory discharge claims brought under Illinois common law. In Illinois, the general rule of law is that non-contractual employees are at-will, which means that they can be discharged by their employer at any time, with or without cause. One of the few exceptions to this general rule is the common law tort of retaliatory discharge. Under this narrow exception, Illinois employers cannot fire employees in retaliation for the …