Will the US government really allow a state to go bankrupt?

As the news stories continue to come out about Puerto Rico and now Illinois, I'm wondering if states and territories can fall under the umbrella of "too big to fail". We continue to hear about Illinois being $14-15 Billion in the hole on its liabilities, and being massively unfunded in its state pension fund. It's all starting to sound like Greece. I have a cousin and her husband both retire last year. They were state employees in Illinois. They are in their mid fifties and are now receiving pension benefits for the rest of their lives........or so they think anyway. They even had the audacity to move from Illinois to Missouri in retirement. So now the state can't even get any of that pension money back in property tax or sales tax from them. At what point will it all come crashing down? I know the state of Illinois promised them this pension. But private pension funds promised their people too. Yet will one get bailed out and the other not? Since the state of Illinois can't print their own money. And they are considered lousy borrowers. What happens when the checks all bounce? I actually asking here. Because it doesn't make any sense anymore. If anyone has any input, I would love to here it.