Negotiators worked late Friday night to craft a statement that all seven leaders could sign. Mr. Trump’s delegation objected to the term “rules-based international order” until negotiators compromised by expressing support for “a” rules-based order rather than “the” rules-based order.
In a section on trade, the Americans insisted on using the word “reciprocal,” one of Mr. Trump’s favorite terms. They compromised by expressing support for “creating reciprocal benefits.” They did not refer directly to the Iran nuclear agreement, which Mr. Trump just pulled out of, but the Europeans included a reference to the United Nations Security Council resolution that endorsed the deal.
The negotiators included agree-to-disagree language on climate change and on an international commitment to reduce plastics in the world. And then the statement was released on Saturday night, only to have Mr. Trump disavow it. Mrs. May learned only as her helicopter arrived at the airport for her to board her plane to return to London.
“It started out as a good summit because we were actually talking to each other, instead of past each other,” said Peter Beyer, the German government’s coordinator on trans-Atlantic relations. But he added, “It looks like the U.S. is no longer a reliable partner in international agreements, and that’s bad.”
Josef Braml of the German Council on Foreign Relations said Mr. Trump considered diplomacy a waste of time. “He is about to destroy what’s left of the liberal world order because he thinks rules and institutions help America’s rivals, China and Europe,” he said.
Laurence Nardon, director of the North American program at the French Institute of International Relations in Paris, said Mr. Trump’s behavior was a negotiation trick. “It’s like when a person leaves the room and slams the door, but is hoping the other person will run after them and follow them into the corridor,” she said.
In Washington, Democrats and some Republicans were upset at the outcome. But Mr. Trump received support from a few Republicans who cheered his tough stance.
Representative Peter T. King, Republican of New York, called the episode a “warning shot to Kim Jong-un” in keeping with Mr. Trump’s approach to negotiations. “This is the Trump style of getting things done,” he said. As to the wisdom of such a public clash, he said, “It depends on how it turns out. This president lives on a high wire, and so far it’s been working.”