During his first term in office, President Trump described the European Union “as a foe,” established “to hurt the United States on trade.”

He repeated the charge at a cabinet meeting on Wednesday, but in more vulgar terms: “The European Union was formed in order to screw the United States. That’s the purpose of it, and they’ve done a good job of it.”

Then he said he was preparing to hit Europe with 25 percent tariffs on cars and other goods.

After Mr. Trump’s embrace of Russia and his warnings that Europe had better fend for itself, the president’s latest attack added to the increasing view of European leaders and analysts that he and his team of loyalists consider America’s traditional allies in Europe as adversaries not just on trade, but on nearly everything.

Some officials and analysts see the Trump administration as merely indifferent to Europe; others see open hostility. But there is a common view that the fundamental relationship has changed and that America is a less reliable and predictable ally.

Mr. Trump has rebuffed NATO and aligned himself with the longstanding, principal threat to the alliance: Russia. Vice President JD Vance has attacked European democracy while calling for the door to be opened to far-right parties. Elon Musk, the billionaire Trump aide, has heaped contempt on European leaders and openly endorsed an extremist party in Germany.

Equally shocking to European leaders, the United States this week refused to condemn Russia’s invasion of Ukraine at the United Nations. It instead broke from its allies and voted with Russia, Belarus and North Korea, all authoritarian governments.

European leaders are scrambling to assess and mitigate the damage. The prime minister of Britain, Keir Starmer, arrives at the White House on Thursday — the second such visit this week, after President Emmanuel Macron of France — still hoping to persuade Mr. Trump not to abandon Ukraine and to remain engaged in Europe. But Mr. Trump describes himself as a disrupter, and Mr. Macron got little for his attempt at seduction.

Friedrich Merz, 69, the conservative politician likely to be Germany’s next chancellor, has expressed strong doubts about the trans-Atlantic relationship he and his country have been committed to for decades.

On Sunday evening, after his party won the most votes in the German election, Mr. Merz said that after listening to Mr. Trump, “it is clear that the Americans, at least this part of the Americans, this administration, are largely indifferent to the fate of Europe.”

He wondered whether the American nuclear umbrella over NATO would remain — and even whether the alliance itself would continue to exist.

“My absolute priority will be to strengthen Europe as quickly as possible so that, step by step, we can really achieve independence from the USA,” he said.

His comments were a remarkable measure of the dismay felt by European leaders over the American reversal of policy on Ukraine and, perhaps more so, for its outright backing of far-right parties that despise European governments and support Russia.

Mr. Merz’s remarks were reminiscent of a 2017 statement by Angela Merkel, then the German chancellor, after contentious alliance meetings with Mr. Trump. “The times in which we could rely fully on others — they are somewhat over,” she said. She encouraged Europeans to “take our fate into our own hands.”

Her comments were considered a potentially seismic shift, but a real reorientation of European security policy never materialized. Matters are more serious now, said Claudia Major, who directs security policy at the German Institute for International and Security Affairs.

“In Munich, Vance declared a culture war and said: ‘Join us or not. We have the right values and you have it wrong,’” she said. His speech, she added, made it clear that “the country that brought us back our freedom and our democracy is turning against us.”

She is not alone in the assessment. Several analysts said the Trump administration’s actions showed that it was not merely indifferent to Europe, but was out to undo it. The distinction holds real consequences for how Europe can respond.

“There is no question the intention is there to destroy Europe, starting with Ukraine,” said Nathalie Tocci, director of Italy’s Institute of International Affairs. “The empowering of the far right is instrumental to the goal of destroying the European Union.”

The reason, she said, is that the Trump administration sees Europe not merely as a competitor, but also as an economic and even ideological threat. It wants to undermine the power of the European Union to regulate trade, competition and hate speech. The latter is a major topic for Mr. Vance, as he criticized what he called news media censorship and political correctness.

The European Union is the largest trading bloc in the world, capable of striking back against Washington economically and in tariff terms, representing the “economic foe” Mr. Trump railed against in his first term.

That power is being used against high-tech and social media companies whose leaders surround and subsidize Mr. Trump, like Mr. Musk, who owns the social media platform X. They, too, have an interest in weakening “the Brussels Effect,” as Anu Bradford of Columbia University Law School called it.

The Brussels Effect is the power of the European Union to establish global rules and norms, and it is particularly important in the realms of climate regulations, digital competition, platform accountability and artificial intelligence.

But if the Trump administration feels it necessary to destroy that threat, then there is little European nations can do to appease the White House, some warned.

If Mr. Trump and his team “are out to push the far right and destroy European democracy, then no amount of European purchasing of American LNG or weapons will matter,” said Ms. Tocci, of Italy’s Institute of International Affairs. By increasing dependency, she added, “it could be a kind of double suicide.”

U.S.-European relations tend to go in cycles, with important strategic debates in the past over Iraq or Afghanistan or even Vietnam. But now the clashes are simultaneously ideological, strategic and economic, said Camille Grand, a former NATO and French official with the European Council on Foreign Relations.

“Facing hostility on all three fronts at once is quite a shock to Europeans,” said Mr. Grand. “Adding all three together you can wonder whether you are no longer a partner but a rival and, perhaps, even an adversary.”

Every country in Europe is doing a reassessment of where it is vis-à-vis Washington, he said. What isn’t clear is whether, as in Mr. Trump’s first term, “you have an unpleasant roller-coaster ride that leaves you sick but you end up where you started, or whether the whole relationship now derails.”

Linas Kojala, director of the Geopolitics and Security Studies Center in Vilnius, Lithuania, urges calm, because “there is no real alternative to the U.S. security guarantee” for a long time to come. “Declaring the trans-Atlantic relationship has collapsed would be like stepping off a ship in the middle of the ocean with no other vessel in sight.”

So for now, he said, “Europe must swallow” the Trump criticism and “do everything possible to keep the relationship intact.”

But it is unlikely to return to where it was, Alex Younger, a former chief of Britain’s foreign intelligence service, MI6, told the BBC last week. “We are in a new era where, by and large, international relations aren’t going to be determined by rules and multilateral institutions,” he said, but “by strongmen and deals.”

Matthew Kroenig, a former defense department official who is now at the Atlantic Council in Washington, calls himself a “normal Republican” and says that “there has been a bit too much hysteria over the past couple of weeks.”

After all, Mr. Kroenig said, the first Trump term was also marked by “a lot of tough rhetoric against allies and a lot of deferential language toward Putin, but in the end, NATO was strengthened.”

Others are less sure.

Mr. Trump has been engaged in “a policy of rapid, unilateral concession of long-held positions on fundamental interests to persuade the aggressor to stop fighting,” said Nigel Gould-Davies of the International Institute for Strategic Studies, speaking of Russia in Ukraine.

“The established name for such a policy,” he said, “is ‘strategic surrender.’”

Whether it will produce the outcome Mr. Trump desires is not clear, he said. What is clear is that it is undermining allied trust in the credibility and common sense of the United States.

It is imperiling old allies in Europe.

And it is “making Russia a more powerful, assertive and attractive ally to America’s adversaries around the world,” he said.