Illinois is like Venezuela now, a fiscally broken state that has lost its will to live, although for the moment, we still have enough toilet paper.
Illinois’ politicians have for decades been giving public employees with pension plans that are basically ponzi schemes and now the state is out of money. They can’t legally declare bankruptcy and raising taxes will drive more taxpayers to Wisconsin or Indiana.
If you want to prevent this from happening in your state, they best thing to do is go the Wisconsin rout and sharply limit the bargaining rights of public employee unions because government bargaining with government over your money is just a bad idea.
States should find a way to reduce the power of cities like Chicago over state governments. City politicians loot the city treasury handing out favors to public employees and voters back in their neighborhood, and raise taxes to cover the holes in the budget, chasing taxpayers to the suburbs. The holes in the budget get so big that the the city representatives in the statehouse try to force the state to assume the debt. If they lose, you get Detroit, which never managed to force Michigan to pay for its 3rd world style politics and had to declare bankruptcy. If the city pols win, you get Illinois.
California has been in the same spot for a decade or so and they have figured out budget and tax tweaks to avert collapse, and I am sure Illinois will do the same. But like California, it is unlikely that Illinois will ever deal with its structural problems and instead just be content with managing its decline. A recession or unforeseen problem will be disastrous.