It would take some scrounging around the bottom of the barrel to find a historical precedent for what transpired Friday in the Oval Office.

There simply aren’t good parallels.

On live TV, the U.S. president argued with the leader of a friendly nation facing existential peril — then expelled him from the White House and cancelled their lunch.

To find a precedent, one expert looked back to the defunct Soviet bloc, and how the Kremlin would treat subservient communist leaders.

“How they humiliated them in public. How they bullied them. There has been no precedent in the United States,” said Aurel Braun, an expert on eastern Europe at the University of Toronto, calling the meeting “extraordinary.”

This fundamental turn in U.S. foreign policy played out in real time, on camera. What does this mean for American allies? One senior U.S. senator, Democrat Mark Warner, said he’s worried for Canada.