Ousted Republican senator Bill Cassidy has suddenly discovered the separation of powers, accusing President Trump of treating Congress as "merely an appendage" in the prosecution of the Iran war — a constitutional concern the Washington establishment rarely voices when one of their own occupies the White House.

Cassidy, who lost his seat after Trump backed challenger Julia Letlow in May's Republican primary, let loose on CBS News' Face the Nation after a closed-door clash with the president over a war powers resolution. The founding fathers designed the separation of powers, Cassidy said, "so that there would not be too powerful of an institution of a presidency" and so that it would "reflect all of the American people, not just the will of one person."

Fair enough on the constitutional text. The question ordinary Americans ought to ask: where were all these Article I champions when Biden governed by executive order for four years? The establishment only rediscovers Congress exists when it can be weaponized against a populist president.

The clash itself was real enough. Trump "berated" Cassidy and three other Republican senators who voted for the resolution, according to The Guardian. Cassidy told Face the Nation he let his "Irish temper" take over. "I raised my volume to match his," he said. Cassidy later said Trump was "attempting to bully me from asking a question that I think the American people need to know, and I'm not going to be bullied," Politico reported.

But here is where the story curdles. After receiving a special briefing from Vice President JD Vance and special envoy Steve Witkoff, Cassidy dropped his support for the very resolution he had just claimed was a matter of constitutional principle. "They said right now the negotiations are delicate, and they could collapse if they're not nursed along in the appropriate way. I can accept that," Cassidy told Politico. So the constitutional crisis lasted exactly as long as it took to get a meeting.

On the war itself, Cassidy offered a blunt assessment that the establishment would rather bury. "A medium-sized power at this point is perceived to have fought a superpower to a draw," he said, noting the conflict has cost $29 billion and claimed 13 American lives. Senator Roger Marshall of Kansas offered the party line on NBC's Meet the Press: "I don't think the war is over [but] we're making great progress. So I'm asking America to hang in there."

Twenty-nine billion dollars and thirteen American lives — and one senator's constitutional scruples dissolved after a closed-door chat with the vice president. Cassidy also took a shot at Trump's domestic agenda, saying the president should focus on "how we make life more affordable for the average American" rather than the Save America Act's federal voting restrictions. "If I were president, I'd be focused on what a family around the kitchen table is looking at as they go through their bills," he said.

Cassidy voted to convict Trump on impeachment charges after January 6, 2021. Trump returned the favor by backing Letlow, who won Saturday's runoff. The constitutional lecture comes from a man who has nothing left to lose and nothing he managed to change.