According to the Illinois supreme court, the state cannot diminish the pensions in any way. They are reading this to mean that they can’t even change the deal in the future. So, short of firing all Illinois workers and re-hiring others under a new plan. Illinois is stuck paying out these pensions for every current worker from now on.
Good luck with that. That isn't even a "Contract" enforced by the Courts, that is some pre-Magna Carta edict that is divorced from the reality of the Accounting Equation.
Bankruptcy would be an option but post the GM keeping the Pension alive and the fact that it is Illinois we are dealing with an alternate universe. Time to leave their before the defecate hits the rotary oscillator...