The United States comprises fifty States. This federal system allows individual States to govern themselves within this Federation of States. So the 50 States may apply different solutions to State endeavors, and an intelligent populace across the Country can judge how things work out elsewhere and, . . . maybe, . . . even, . . . apply "lessons learned" to improve their own State governance by adopting or rejecting other State policies.
F'r example, The Prarie State [aka Illinois, aka The Sucker State ref: State Nicknames ] has promised its employees pensions which it cannot pay, EVER. [The only State-Pensions less well-funded than Illinois are: those in Kentucky and New Jersey.]
Lesson learned: Don't govern like Illinois, Kentucky and New Jersey.
[Oh, and not-so-incidently the top-funded State pensions are those of Wisconsin, South Dakota, and Tennessee.
Lesson Learned: . . . . Wait a minute ! ! ! Tennessee ! Why, . . . that's where poor old DonDiego has chosen to reside. Hmm, . . . maybe that bit above about citizens learning from other States' successes and failures really means something after all.]
It is not up to the federal-taxpayers to pay-off Illinois' pension obligations. It is not up to the tax-payers of 49 other States to pay-off Illinois pension obligations.
Unfortunately it is unconstitutional for a US State to declare bankruptcy.
The State of Illinois could live within its means. Oh, wait. It's too late for that.
The State of Illinois could borrow the money by issuing bonds. Of course, given the profligate history of Illinois' spending the interest will pr'bly be high.
The State of Illinois could sell State assets. Although, DonDiego notes there is nothing in Illinois which he would want.
In his meandering the internets poor old DonDiego has come across an article addressing the Illinois dilemma:
Forbes
an excerpt: ". . . . . in Illinois, it has long been a part of the state’s response to economic crises to abandon its pension contributions, so that the state is now paying significantly more than that basic annual accrual cost, to reach a 2045 90% funding target, and this is what’s driving the high contribution levels, so much so that a full quarter of the state’s general revenue is directed towards pensions."
Lesson Learned: If one abandons making regular payments into the pension funds, there will not be enough to pay the pensions when they come due.