I would imagine NASA / .gov has some sort of SLA clause in the contract with SpaceX? Perhaps they can clawback the money they paid or otherwise sue for damages.

Seems like Musk is not thinking properly. They own the courts, they can file claims against him, freeze his funds, and tie him up in court for years if they want to.

I don't have a dog in this fight, but I sorta do think that Musk must be on drugs.