It is disquieting to recall the moving ceremony on the beaches of Normandy that marked the 80th anniversary of D-Day 11 months ago, a celebration of the ironclad alliance between the United States and Europe, and their shared resolve to meet “the test of ages” and defend Ukraine.

That phrase from former President Joseph R. Biden Jr., standing shoulder to shoulder with President Emmanuel Macron of France, was part of an address in which he proclaimed NATO “more united than ever” and vowed that “we will not walk away, because if we do, Ukraine will be subjugated and it will not end there.”

I stood in the Normandy sunlight, musing on the young men from Kansas City and St. Paul and elsewhere who clambered ashore on June 6, 1944, into a hail of Nazi gunfire from the Normandy bluffs, and listening to words that drew a direct line between their singular courage in the defense of freedom and the struggle to defeat another “tyrant bent on domination.”

That “tyrant,” for Mr. Biden, was President Vladimir V. Putin of Russia, since absolved of responsibility for the war he started in Ukraine by President Trump, the America-first leader who has been a perennial coddler of autocrats, denigrator of NATO, and opponent of a European Union formed, in his words, to “screw the United States.”

Never did I imagine, less than a year ago, that so much so dear to so many could unravel so fast; nor that the 80th anniversary on Thursday of V-E Day, or Victory in Europe, would come with so many Europeans no longer sure whether to regard Mr. Trump’s America as ally or adversary.

American troops wading ashore in Normandy, France, in the first wave of D-Day invasion, on June 6, 1944.Credit…Robert M. Sargent/United States Coast Guard