Birthday parties for international treaties are never raucous affairs. But when old trade hands gathered in the pavilion of Washington’s Ronald Reagan building on a recent evening to celebrate the 70th birthday of the General Agreement on Tariffs and Trade — the 1947 document that still guides international commerce — the mood was decidedly maudlin.

“This feels more like a wake than a birthday party,” grumbled one veteran trade negotiator after listening to a procession of speakers extol the virtues of the Gatt and warn of a looming protectionist tide.

The reason, he did not have to add, was sitting just a few blocks away in the White House. A year on from Donald Trump’s election as US president, the populist property tycoon is delivering on his promise to shake up the international system. Viewed from Washington, the future of global trade now seems to be predominantly about ripping up its glorious past.