President Emmanuel Macron’s visit to Washington was certainly grand theater: the hugs and kisses with President Trump, the dandruff whisked off his lapel, the first lady’s broad white hat, and then the 40-year-old French wunderkind rising before Congress to deliver a stern lecture in elegantly accented English on why the American president is wrong about multilateralism, protectionism, nationalism, Iran and climate change.

Mr. Macron no doubt planned the bait-and-switch for some time. Other world leaders have tried different approaches to dealing with Mr. Trump, from joining him in a game of golf, as Prime Minister Shinzo Abe of Japan did, to openly rebuking him, as President Enrique Peña Nieto of Mexico did this month. None have really worked.

Nor is there much likelihood that the young French president, not yet a year in office, will have changed Mr. Trump’s mind in any meaningful way, even after being proclaimed “perfect” by his host. At a meeting with a group of journalists on Wednesday evening, Mr. Macron said that contrary to common wisdom, he found Mr. Trump to be “very predictable,” which would suggest that he did not expect the American president to be swayed by his Gallic reason. He acknowledged that he expected Mr. Trump to opt out of the Iran nuclear deal, and his goal, Mr. Macron said, was to position himself as an “honest broker” for the aftermath.

If he achieves even that, it won’t be a bad outcome from the meeting. Mr. Macron’s goal from the outset of his presidency has been to assert France as the leader on global issues like climate change, European unity and resistance to right-wing nationalism and authoritarianism, and toward that end he has sought to forge comradely relations even with leaders who hold opposing views, whether by hosting the Russian president, Vladimir Putin, in the imperial splendor of Versailles or getting touchy-feely with Mr. Trump.