One of the few concrete pledges to come out of the Group of 7 summit in Biarritz, on France’s Atlantic coast, was an aid package of $20 million for Brazil and its neighbors in the Amazon basin to fight fires raging through the rainforest. The sum was a trifle, given the scale of the fires and the size of the economies of the donors (the charity of the actor Leonardo DiCaprio separately pledged $5 million), but it was meant to highlight a more ambitious program of protection and reforestation in the works.

More noteworthy than the token action was the fact that President Trump skipped the session at which it was taken, which happened to be devoted to climate, oceans and biodiversity. Even more noteworthy was that neither French President Emmanuel Macron, the convener of this year’s summit and champion of action on the Amazon fires, nor hardly anyone else seemed to find this particularly disturbing.

In fact, they seemed relieved. Other American officials were there, said Mr. Macron, and it had never been his goal to challenge Mr. Trump’s climate denialism. In fact, he said he and the American president had a “long, rich and totally positive” discussion on the Amazon fires. Maybe they did, but by now Mr. Macron should know better than most that the Trump who likes being agreeable face to face can quickly turn mean at a distance.

That, in fact, was the real theme of the Biarritz summit in the third year of the Trump presidency, as described by Peter Baker of The Times: “Rule 1 at the G7 Meeting? Don’t Get You-Know-Who Mad.” Mr. Macron cautiously avoided trying to draft a joint communiqué, perhaps recalling how Mr. Trump pulled his signature off the one reached last year in Canada in a tantrum over something Canadian Prime Minister Justin Trudeau said.