The False Claims Act (FCA) allows third parties to sue on behalf of the United States for fraud committed against the United States. Per the Act a FCA complaint is kept secret “under seal” until the United States can review it and decide whether it wants to participate in the case.
In State Farm Fire and Casualty Co. v. United States ex rel. Rigsby the Supreme Court held unanimously that if the seal requirement is violated the complaint doesn’t have to be dismissed.
While the Supreme Court has yet to rule whether states and local governments can bring FCA claims, local governments, but not state governments, can be sued for making false claims against the federal government.