On Tuesday, a three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit announced its decision in the case of the United States v. Trump, on the question of the former president’s immunity — or lack thereof — to federal criminal prosecution. The panel isn’t having it.

“We cannot accept that the office of the presidency places its former occupants above the law for all time thereafter,” the opinion reads. “Former President Trump lacked any lawful discretionary authority to defy federal criminal law and he is answerable in court for his conduct,” the judges add.

Of course, this is not the end of the road for Trump. He will appeal the decision, and the case will almost certainly be taken up by the Supreme Court, where our eminent tribunal will decide whether the former president is immune from criminal prosecution for illegal acts done in office under the auspices of executive authority.

It might be tempting to set the panel’s opinion aside, knowing that the story isn’t over yet. But you shouldn’t. It is a fascinating document, not the least because the judges provide a full portrait of the radicalism of Trump’s claim to executive immunity.

In short, the former president says that he has “absolute immunity from criminal prosecution for all ‘official acts’ undertaken as president,” a claim that rests on the constitutional doctrine of separation of powers. As his lawyers wrote in their brief, “The president is vested with the executive power. The judicial branch may not sit in judgment, criminal or otherwise, over his exercise of that power.” The rest of the argument — from constitutional text, from history and from the practical considerations of governance — flows from that point.

It is true, the panel says, that “the Supreme Court has explained that a former president is absolutely immune from civil liability for his official acts.” This includes acts that fall within the “outer perimeter” of his official responsibilities. What Trump wants is for the courts to “extend the framework for presidential civil immunity to criminal cases and decide for the first time that a former president is categorically immune from federal criminal prosecution for any act conceivably within the outer perimeter of his executive responsibility.”