It’s said to be implicit in all contracts that all parties are acting in good faith - exhibiting fairness, reasonableness, and decency. I wonder if they could void the contract on those grounds.
“I wonder if they could void the contract on those grounds.”
Local and state governments are sovereign. No past legislative body can bind a future legislature to previous actions. If that were the case, there would be no need to hold elections to change the direction of previous legislation. There is no such thing as an omnipotent legislature that can pass plenary law.
These contracts can be cancelled by the current Detroit legislative body at any time unless there is a state law that prevents it.
In fact, back in the 1990s, the federal courts made several rulings stating that local governments are sovereign and the federal government cannot force them to enforce federal laws.