For some Europeans, the most embarrassing revelation of the now very public phone conversation between Donald Trump and Ukraine’s president on July 25 was not the attempt by Mr. Trump to interfere in the judiciary system of a foreign country for his own political benefit. Nothing the American president does could surprise any longer.

What they found particularly disappointing, instead, was the servility with which his young counterpart, Volodymyr Zelensky, sought to ingratiate himself with Mr. Trump, pretending that he had won the Ukrainian presidency by imitating him, claiming to have appointed a new prosecutor general who would be “100 percent my person,” and happily joining in the Euro-bashing that has become one of Mr. Trump’s trademarks.

Masks were falling off. So this popular maverick comedian turned real-life politician after playing one in a TV series, this promising reformer that President Emmanuel Macron of France had hosted at the Élysée even before he was elected, was in fact another spineless, unprepared leader jumping into President Trump’s every trap.

Chancellor Angela Merkel of Germany and President Macron have been wise enough not to comment on this pathetic turn of events. Privately, French diplomats insist that Paris still actively supports Mr. Zelensky — even more so in light of the American meltdown. What is at stake in Ukraine for the European Union is far too important, and the risk of seeing Mr. Trump’s dirty work derail laborious efforts to reform that post-Soviet country far too real.