President Joe Biden marked the 80th anniversary of D-Day on Thursday by pledging “we will not walk away” from Ukraine, drawing a direct line from the fight to liberate Europe from Nazi domination to today’s war against Russian aggression.

“To surrender to bullies, to bow down to dictators, is simply unthinkable,” he said during a ceremony at the American cemetery in Normandy. “If we were to do that, it means we’d be forgetting what happened here on these hallowed beaches.”

D-Day was the largest amphibious assault in history, and Biden called it a “powerful illustration of how alliances, real alliances make us stronger.” He said that was “a lesson that I pray we Americans never forget.”

The comment by the Democratic president was a reminder that American commitments around the globe hang in the balance during this year’s U.S. election. Donald Trump, the presumptive Republican nominee, has said he would not defend European allies that are “delinquent” in their own security spending.

The possibility of Trump’s return to the White House has left many of the continent’s leaders fearful that transatlantic unity, which was sealed in blood on D-Day and strengthened in response to Russia’s invasion of Ukraine, could fray or even rupture.

Trump has expressed little enthusiasm for Ukraine’s defense, criticizing the “endless flow of American treasure” and calling for Europe to shoulder more of the burden. He has also voiced admiration for Russian President Vladimir Putin.

Trump shared his own D-Day anniversary message on social media, praising U.S. soldiers as “immortal heroes.” He was silent on the country’s alliances.

Concerns about American reliability extend beyond Trump. Biden struggled to secure bipartisan congressional approval for U.S. military assistance for Ukraine, and months of delay contributed to Russian advances on the battlefield.

Ukrainian President Volodymyr Zelenkyy was in Normandy for anniversary events on Thursday and is expected to sit down with Biden in Paris on Friday. It will be their first meeting since Biden signed legislation with new money for Ukraine’s defense, and Zelenskyy has continued to push for faster and more aggressive U.S. support.

One such step took place recently, when Biden eased limitations on how Ukraine can use American weapons, allowing for some strikes into Russia in order to defend Kharkiv, a city near the border between the two countries.

Putin reacted angrily, saying he is prepared to use nuclear weapons to protect Russian sovereignty and suggesting that he could provide Russian weapons to those willing to strike Western targets.

The war and persistent threats of escalation were an ominous backdrop to the D-Day ceremony, and Biden warned that “democracy is more at risk across the world than any point since the end of World War II.”

While paying tribute to the American troops that stormed Normandy’s beaches on June 6, 1944, Biden said “let us be worthy of their sacrifice.”

“We must remember that the fact that they were heroes here that day does not absolve us of what we have to do today,” he said. “Democracy is never guaranteed. Every generation must preserve it, defend it and fight for it. That’s the test of the ages.”

Biden also highlighted “hundreds of thousands of people of color and women who courageously served despite unjust limitation on what they could do for their nation.”

Before the ceremony, Biden and first lady Jill Biden met with more than two dozen American veterans near Omaha Beach, where the fiercest D-Day fighting took place. Those who could stand were helped out of wheelchairs to pose for photos. Most shook hands with Biden or saluted; one hugged him.

Biden told a veteran that “you saved the world.” The president led the audience in singing happy birthday to another. Steve Spielberg and Tom Hanks, the Hollywood heavyweights behind movies and television shows about World War II, were nearby.

When Army veteran Robert Gibson approached, the first lady clutched his arm to help him stand next to the president as they shook hands.

“Don’t get old,” the 100-year-old man from New Jersey joked to the 81-year-old president, who was a toddler on D-Day.

This anniversary of the invasion is a particularly somber one because it will be among the last with living veterans. The youngest survivors are in their late 90s. Biden met one veteran who is 104.

In an interview with The Associated Press a few days ago, Gibson described himself as “living on borrowed time.”

He was part of the second wave of troops that landed on Utah Beach. Gibson said he expected this year would be the last anniversary ceremony that he could attend, but he was pleased to be back one more time.

“I want to see the beach again,” he said.

At the end of his visit to the American cemetery, Biden paused in front of the grave of John S. Greenfield, an Army private first class from Delaware. Greenfield landed at Omaha Beach with the 115th Infantry Regiment of the 29th Infantry Division.

As his regiment fought inland, Greenfield was killed during a German ambush, 10 days after D-Day. Greenfield’s family learned of his death when a package of cigarettes that has been mailed to him as a gift was returned undelivered, according to the Wilmington Morning News. The word “deceased” had been written over his name.

Standing at Greenfield’s grave, Biden made the sign of the cross and touched the letters engraved on the white marble headstone.

(AP)