“An amendment properly drafted and broad enough would eliminate all legal issues under Illinois law—it could be written to supersede not just the pension protection clause but all state constitutional issues.  … Why hasn't this already been done? Aside from the obvious—no political will—a lawsuit in federal court alleging violation of the Contract Clause in the U.S. Constitution is possible. That clause prohibits states from passing any law that 'impairs the obligation of contracts.' …”