President Trump is no fan of the European Union. He has repeatedly claimed that the bloc was created to “screw” America, has pledged to slap big tariffs on its cars, and this week enacted global steel and aluminum levies that are expected to hit some $28 billion in exports from the bloc.

But for months, E.U. officials hoped that they could bring the American president around, avoiding a painful trade war. They tried placating the administration with easy wins — like ramped-up European purchasing of U.S. natural gas — while pushing to make a deal.

It is now becoming clear that things won’t be that simple.

When American tariffs on steel, aluminum, and products that use those metals kicked in on Wednesday, Europe reacted by announcing a sweeping package of retaliatory tariffs of its own. The first wave will take effect on April 1, imposing tariffs as high as 50 percent on products including Harley Davidson motorcycles and Kentucky bourbon. A second wave will come in mid-April, targeting farm products and industrial goods that are important to Republican districts.

European officials have been clear that they were not eager to take that aggressive step: They wanted to negotiate, and they still do.

“But you need both hands to clap,” Maros Sefcovic, the European Commission’s trade minister, said on Wednesday. “The disruption caused by tariffs is avoidable if the U.S. administration accepts our extended hand and works with us to strike a deal.”

Mr. Trump reacted to the European Union’s move on Thursday, calling it “nasty” in a social media post and threatening to hit back with a 200 percent tariff on Champagne, wine and other alcohol from France and across the European Union if the bloc does not retreat from its tariffs on whiskey.

As a tit-for-tat trade war kicks into gear, Europe is facing a difficult reality. It is not clear to many European officials what exactly Mr. Trump wants. Tariffs are sometimes explained by administration officials as an effort to level the playing field, but they are also cited as a tool for raising money for U.S. coffers to pay for tax cuts, or floated as a way to punish the E.U. for its regulation of technology companies.

Mr. Trump has said that Europe has “not been fair” with its trading practices, and on Thursday he called the bloc “hostile and abusive.”

On average, Europe’s tariffs are just slightly higher than U.S. tariffs — about 3.95 percent on average, compared to America’s 3.5 percent on European goods, based on an ING analysis. But it is the case that certain products face notably higher tariffs when shipped to Europe — cars, for instance, are tariffed at 10 percent.

Mr. Trump has also taken issue with the way Europe and other nations tax producers, and has suggested that future U.S. tariffs will also respond to those policies. In part because of that, some of the tariff rates he has floated — like 25 percent on cars — would be far above the ones he criticizes in Europe.

Nor has the Trump administration appeared eager to wheel and deal. Mr. Sefcovic went to Washington in February, but he has acknowledged that he made little progress on that trip. President Trump has not spoken individually with Ursula von der Leyen, the European Commission president, since taking office.

Without a clear understanding of what is driving Mr. Trump, and without trusted intermediaries within the administration, it is hard to figure out how to strike a deal that will prevent pain for consumers and companies.

“It doesn’t feel very transactional, it feels almost imperial,” said Penny Naas, a trade expert at the German Marshall Fund. “It’s not a give and take — it’s a ‘you give.’”

That is why the E.U. is now underscoring that it can hit back if forced, and that there will be more to come if the Trump administration goes ahead with the additional tariffs that it has threatened. The bloc is aiming to keep its measures proportionate to what the U.S. is doing, in a bid to avoid escalating the conflict.

But it has also been preparing for months for the possibility of an all-out trade war, even if it hoped to avoid one.

“If they move ahead with those, we will respond swiftly and forcefully, as we have today,” Olof Gill, a European Commission spokesman, said during a news conference on Wednesday. “We have been preparing assiduously for all of these outcomes. We showed today that we can respond swiftly, firmly and proportionately.”

The question is what might come next.

Mr. Trump has promised additional tariffs on European goods, including so-called reciprocal tariffs that could come as soon as April 2. He’s also talked about significantly ramping up tariffs for specific products, like cars.

“It’ll be 25 percent, generally speaking, and that will be on cars and all other things,” Mr. Trump said in late-February comments in the Oval Office. “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, but now I’m president.”

European officials have been clear that if things get bad enough, they could use a new anti-coercion tool that would allow them to put tariffs or market limitations on service companies. That could mean technology firms, like Google.

While Europe sells the United States more physical goods than it buys from it, it runs a big deficit with the U.S. when it comes to technology and other services — in large part because Europeans are a big market for social media and other internet-based companies.

Mr. Sefcovic has listed the anti-coercion tool as a hypothetical option to “protect” the European market from external meddling, and other European leaders have been more vocal about the possibility of using it on the United States specifically.

But since Europe does not want to worsen the trade war, hitting American technology firms is seen as a tool for more extreme circumstances.

“It’s more the nuclear option,” said Carsten Brzeski, a global economist for ING Research.

For now, European officials are hoping that the threat of retaliatory tariffs will suffice to drag America toward the negotiating table. The measures are expected to hit products that are important in Republican strongholds: Bourbon from Kentucky, soybeans from Louisiana.

As workers and companies stare down bleak forecasts, the theory goes, they will call their political contacts and pressure them to negotiate.

The spirits industry — poised to be hit hard by 50 percent tariffs on whiskey — has already voiced alarm. The industry was seriously affected by an earlier and less extreme version of the retaliatory tariffs during Mr. Trump’s first administration.

“Reimposing these debilitating tariffs at a time when the spirits industry continues to face a slowdown” will “further curtail growth and negatively impact distillers and farmers in states across the country,” Chris Swonger, the chief executive of the Distilled Spirits Council, said in a statement on Wednesday.

Political turbulence is already causing pain for some American companies. Tesla’s sales in Germany plunged in February and have slumped across Europe, highlighting anger at Elon Musk, the company’s chief executive and a close ally of Mr. Trump.

But the administration has indicated a willingness to accept some economic pain in exchange for its long-term trade goals — which involve nothing short of rewriting the rules of global trade.

“There is a period of transition, because what we’re doing is very big,” Mr. Trump said in an interview on Fox News on Sunday.

To Europe, a world where Mr. Trump is bent on reorganizing the global order is a more treacherous one. The unfolding conflict risks permanently undermining its most important trading relationship, one that it has long viewed as mutually beneficial, while damaging its close alliance with the United States.

“There are no two economies in the world as integrated as the United States and Europe,” Ms. Naas said. “Decoupling is not really an option, at the moment, so now we’re going to be stuck in this tariff paradigm.”

Ana Swanson contributed reporting.

On a ship that caught tuna for American consumers, fishermen said they were fed so little that they resorted to eating the bait. On another, a worker said he was beaten repeatedly by the captain, sometimes with a metal hook. On a third, a man who experienced severe burns in a kitchen accident said he was denied medical care and survived only by treating himself with Vaseline.

All three boats offloaded their catch to other vessels, remaining at sea for months. For those who wanted to leave, there was little hope.

These accusations are central to a new lawsuit filed by four Indonesian fishermen. They say they want to right a wrong that, according to them, was tolerated by one of America’s oldest tuna brands, Bumble Bee Foods.

They are suing the company in federal court in California, accusing it of being aware of and benefiting from forced labor on ships operated by its suppliers. Bumble Bee, which is based in San Diego, said it would not comment on pending litigation.

“I want justice,” Muhammad Syafi’i, one of the plaintiffs, said in a Zoom interview from his home in the Indonesian city of Yogyakarta. “For myself, for my fate. And for my friends who are still out there.”

In 2021, he was employed as a cook on a boat that caught tuna that was sold to Bumble Bee (but also had to help with the fishing). He was forced to fork over nearly half of his $320 monthly salary for months. That July, he was severely burned when hot oil from his wok spilled onto the lower half of his body. He said the captain refused to get him medical care for months. Eventually, he was allowed to return home.

Rights groups say the growing global demand for tuna — an industry worth over $40 billion — is abetting human rights abuses. Much of that demand comes from the United States, the world’s largest seafood importer in terms of money. About 80 percent of the seafood eaten in America is imported.

The International Labor Organization, a United Nations agency, estimated in 2021 that there were roughly 128,000 people trapped in forced labor in the global fishing industry. The figure, it said, was most likely higher.

In 2022, the environmental group Greenpeace said that it had been able to track fish caught by a ship that U.S. authorities had flagged as using forced labor, using codes on a Bumble Bee can sold in a grocery store in Arlington, Va. That raised the possibility of more tainted products being on U.S. supermarket shelves.

Bumble Bee, which has been owned by the Taiwanese tuna trading company FCF since 2020, did not respond to those accusations. The next year, the company agreed to remove some claims about its fishing practices from its marketing materials, after it was accused by the Global Labor Justice-International Labor Rights Forum of falsely claiming that its supply chain was fair and safe.

In a report last December, Greenpeace said it had found 10 Indonesian fishermen, who said they were lured by promises of good jobs but later were subjected to violence and hunger every day on the seas. When their ordeal was over, the men said that they often ended up with little or no money.

The accounts from Greenpeace helped form the basis of the lawsuit, which was filed on Wednesday in a U.S. District Court in San Diego. The plaintiffs sued under a law that authorizes survivors of human trafficking, regardless of their citizenship, to sue companies that knew or should have known that they were benefiting from forced labor.

The lawsuit, filed by Mr. Syafi’i and three others, Akhmad, Angga — both of whom go by one name — and Muhammad Sahrudin, seeks unspecified monetary damages from Bumble Bee.

Many of the workers onboard such tuna ships are often poor Indonesians, who are lured by brokers with the promise of high pay. Enforcement of labor laws is often weak in Indonesia, especially in informal sectors like fishing. Rights groups say there is also a lack of official oversight, making it easy for companies to exploit workers.

Mr. Syafi’i said he was still shaken about his experience on a Chinese-flagged vessel called Lu Rong Yuan Yu 211. He returned to Indonesia in July 2022 and had the first of many surgeries. He says he still cannot lift heavy objects, and his genitals, which were severely burned, have not fully healed. He was given about $6,000 in compensation by the broker who found him the job.

He is now unemployed. “I no longer have the desire to work on a ship, ever again, even if they offer me a huge amount of money,” he said. He says he wants to share his experience with other fishermen before they head out to sea.

Before he took that job, he said a friend had told him, “that life on a boat is work, eat, sleep. Repeat. But in reality, no one dared to be truly open about the real conditions.”

Bit by bit, the traces of Shanghai’s coronavirus lockdown in 2022 have disappeared from around Fu Aiying’s stir-fry restaurant. The smell of rotten eggs, from when officials carted her off to quarantine without letting her refrigerate her groceries, is long gone. The testing booths manned by workers in hazmat suits have been dismantled.

Even her neighbors have moved away, from the century-old neighborhood that had one of the city’s highest infection rates. Soon, the neighborhood itself will vanish: Officials have slated it for demolition, saying that its cramped houses had helped the virus spread. Ms. Fu’s restaurant is one of the few businesses still open, in a row of darkened storefronts and caution signs taped to doorways.

But the boarded-up windows have done little to contain the emotional legacy of that time, a grueling, monthslong lockdown of 26 million people. Some residents, who had prided themselves on living in China’s wealthiest city, found themselves unable to buy food or medicine. They wondered when they might be dragged off to quarantine, forcibly separated from their children.

Ms. Fu spent 39 days in a mass quarantine center, with no idea of when she’d be allowed out. After she was finally released into the still-locked-down city, she had to sneak into her restaurant for rice and oil, because she didn’t have enough food at home.

She felt like a part of her had been permanently dulled. “Since my time in quarantine, I don’t have a temper anymore. I don’t have a personality anymore,” said Ms. Fu, 58, tearing up.

Perhaps no country was as deeply reshaped by the pandemic as China, where the outbreak began in the central city of Wuhan five years ago. For three years afterward, longer than anywhere else, the Chinese government sealed the country’s borders. In the final year, 2022, it declared an especially harsh “zero-tolerance” policy for infections, imposing lockdowns like the one in Shanghai, nationwide. Officials insisted on the restrictions even as the rest of the world decided to reopen and live with the virus.

Years later, the shadow of that experience still lingers. In another Shanghai neighborhood, which held the dubious distinction of being locked down the longest — 91 days — one woman said shortages during that time had once forced her to pay $11 for a head of cabbage. She now stockpiles at least a week’s worth of groceries.

Another woman, Yan Beibei, a college counselor in her 30s, once planned to buy a house in Shanghai’s more affordable outskirts. But during the lockdown, her neighbors helped ensure that she had food. Now, she wants to stay near people she trusts, even if that means delaying homeownership.

“You have to figure out which places feel safer,” she said.

Before the pandemic, the ruling Communist Party’s controls could feel distant to many Chinese, or a worthwhile trade-off for the country’s huge economic gains. But the lockdowns made clear that the party was willing to sacrifice those gains, and people’s safety more broadly, at the whims of one man, Xi Jinping.

Local governments spent tens of billions of dollars on testing, vaccination, payments to health care workers and other related costs in 2022 alone, according to incomplete budget reports. Still struggling to recover financially, some localities have delayed payments to civil servants or cut benefits to retirees. Hospitals have gone bankrupt.

Ordinary people are hesitant to spend money, too. Many saw their savings dwindle as the lockdowns forced companies and factories to shut down. Empty storefronts are a common sight even in major city centers. Ms. Fu, the restaurant owner, said business was half what it had been before the pandemic.

Still, Ms. Fu did not want to dwell on her memories. “Even thinking about it is painful,” she said. “Let’s not talk about it.”

The silence may be a coping mechanism for some residents. But it is also carefully enforced by the Chinese government. The restrictions at times set off intense public anger, including the biggest protests in decades.

The government has worked to squelch any discussion about its response to the pandemic, let alone attempts to reckon with it. Art exhibits about the lockdowns have been shut down. Even today, many social media users use code words like “face mask era” to avoid censorship.

The government has also not pulled back much of the expanded surveillance it introduced then. It has urged cities to hire more neighborhood workers who were in charge of tracking residents’ movements during the pandemic, to strengthen monitoring of public sentiment.

On Shanghai’s Urumqi Road, where some of the biggest protests occurred, in 2022, a police truck is still parked at a busy intersection of hip boutiques and restaurants. Some workers at businesses there declined to discuss the pandemic, citing the political sensitivity.

But silence is not the same thing as forgetting. Many Chinese were shaken by the seeming arbitrariness of the restrictions, as well as the abruptness of the government’s decision, in December 2022, to end them. The government had not stockpiled medicine or warned medical professionals before doing so, and hospitals were overwhelmed as infections skyrocketed.

The mother of Carol Ding, a 57-year-old accountant, fell sick in that wave. Ms. Ding managed to secure her mother a much-sought-after hospital bed — other patients slept in the hallways or were turned away, Ms. Ding recalled — but the hospital didn’t have enough medicine. Her mother died.

“If you had so much power to lock people down, you should have the power to prepare medicine,” Ms. Ding said.

She added that time had done little to ease her emotional pain. “I think it’ll take at least 10 years for all this to go away or be diluted,” she said.

To the casual observer, these pandemic aftershocks may not be immediately evident. Tourists once again stroll Shanghai’s glittering Bund waterfront. Hipster coffee shops and soup dumpling joints are again drawing long lines of customers.

The apparent bustle, though, masks a struggling economy. With well-paying jobs hard to find, more and more people have turned to gig work. But their earnings have fallen as their ranks have grown. And they’re scrambling for fewer and fewer dollars, as people cut down on spending.

Lu Yongjie, who runs a parcel delivery station in a working-class neighborhood of Shanghai, said shipping companies once paid him 20 cents per package. That has now fallen to about 14 cents, he said.

Still, he had to accept the lower prices: “If you don’t do it, someone else will.”

If there is a cure for China’s post-Covid hangover, it may lie with what propelled the country’s prepandemic rise: the doggedness and ambition of ordinary people, like Marco Ma, a 40-year-old restaurant owner.

Since the pandemic, Mr. Ma had shut down four of the six locations of his Korean street food restaurant. His fourth-grade son, once a star pupil, now struggled with paying attention, which Mr. Ma attributed to extended online schooling. He kept expecting the next year to be better, but, in reality, business only got worse.

Still, “I think 2025 will be a turning point,” he said. “You grab onto whatever pieces of news, or whatever to cheer yourself up. What can you do? You have to keep living.”

Siyi Zhao contributed research.

A United Nations commission on Thursday accused Israel of targeting hospitals and other health facilities in Gaza that provide reproductive services, including an I.V.F. clinic where thousands of embryos were destroyed, in what it called an effort to prevent Palestinian births.

The report by the U.N. Commission of Inquiry on the Occupied Palestinian Territory, called that and other actions that cause harm to women and girls “genocidal acts” and accused Israel of punishing Palestinians collectively for the Hamas-led Oct. 7, 2023, attack that killed 1,200 people.

Israel’s mission to the United Nations in Geneva immediately rejected the report, saying in a statement that the commission was engaged in “a shameless attempt to incriminate” the Israeli military “to advance its predetermined and biased political agenda.” Israel’s prime minister, Benjamin Netanyahu, accused the United Nations Human Rights Council of attacking the country with “false accusations.”

The commission, set up by the Human Rights Council in 2021 and made up of three lawyers with expertise in human rights, said its report drew on earlier investigations it had carried out since the Hamas attack on southern Israel and on some 25 interviews conducted over recent months with medical experts, as well as victims and witnesses of the violence in Gaza. Some of the testimony was aired over two days of hearings in Geneva this week.

The report marked the first time a United Nations committee has found that Israel has committed genocidal acts under the Rome Statute, which created the International Criminal Court, and under the international treaty that criminalizes genocide.

“Israeli authorities have destroyed in part the reproductive capacity of the Palestinians in Gaza as a group, including by imposing measures intended to prevent births, one of the categories of genocidal acts in the Rome Statute and the Genocide Convention,” the commission said.

Israeli officials have long accused the rights council of singling Israel out, arguing that U.N. officials and committees condemn the country with far greater frequency than it does dictatorships like North Korea. In February, Gideon Saar, the Israeli foreign minister, said Israel would stop participating in the council, accusing it of demonizing Israel.

The Israeli military’s bombardment and invasion decimated Gaza’s health care system in a way that aid groups and international bodies have called “systematic.” The report said this included damage to clinics and other facilities that provide maternity services affecting more than half a million women and girls of reproductive age in Gaza.

Israel has said that Hamas fighters have embedded themselves in hospitals and other buildings. Under international law, if there is doubt about whether a hospital is being used for military purposes, it should be presumed not to be, according to the Red Cross, and civilians should not be targeted.

The report cited in particular the destruction of Al Basma I.V.F. clinic, Gaza’s largest fertility clinic, which was destroyed in December 2023 by artillery fire, which is typically less accurate than missiles. The commission heard from expert witnesses that the clinic’s destruction caused the loss of some 4,000 embryos and other reproductive material from Palestinian patients for whom it often represented a last chance to have children.

The circumstances of the destruction of the clinic are not entirely clear, but Chris Sidoti, a member of the panel, said at a news conference that Israeli military commanders had detailed knowledge of the location and services provided by all the medical facilities in the enclave.

The commission said that it did not find any evidence that the facility was a legitimate military target at the time that it was attacked by Israeli forces. “It is not possible to say the destruction of the building was unintentional or accidental,” Mr. Sidoti said.

The Israeli military did not immediately respond to a request for comment on the claim.

The commission also said that Israel’s blockade of Gaza, which curbed humanitarian aid and access to medical care, had caused severe reproductive harm to women and girls, which it said was calculated to bring about the physical destruction of Palestinians as a group. Women and girls died from pregnancy and childbirth complications because of Israel’s siege, the commission said. That, it declared, amounted to the crime against humanity of extermination.

The commission also documented what it said were wide-ranging abuses, including forced stripping and nudity, sexual harassment, rape or threats of it, and the sexual torture of detainees, which it said had become standard operating procedures for Israeli security forces toward Palestinians.

Israeli forces who invaded Gaza after the Oct. 7 attack have detained men, women and children by the thousands. The New York Times has previously reported on accounts by nearly a dozen detainees or their relatives who described being stripped, beaten, interrogated and held incommunicado. Israeli military officials say that soldiers routinely order detainees to strip for security reasons to be sure that they are not carrying weapons, including explosive vests.

The U.N. committee said that the frequency, prevalence and severity of sexual and gender-based violence showed it has been “increasingly used as a method of war by Israel to destabilize, dominate, oppress and destroy the Palestinian people.”

The U.N. panel also said it had documented cases of rape and severe physical assaults carried out against Palestinian detainees in Israel’s Sde Teiman detention center. An Israeli military prosecutor charged five reservist soldiers with abuse of a Palestinian detainee, including using a sharp object to injure his rectum. But the commission noted that the five were not ultimately indicted for any sexual offense, although prosecutors had initially suspected them of doing so.

The commission said that it had not seen evidence that the Israeli authorities have taken any effective measures to prevent acts of sexual violence and that it had not seen any move to identify and punish perpetrators despite witness and other evidence.

On the contrary, “the lack of effectiveness shown by the military justice system to prosecute cases and convict perpetrators sends a clear message to members of the Israeli Security Forces that they can continue committing such acts without fear of accountability,” Navi Pillay, a former U.N. human rights chief and the commission’s chair, said in a statement released with the report.

Israel’s mission said that Israeli military orders unequivocally prohibit sexual violence and that any allegations were investigated in accordance with international norms.

Previous commission reports to the U.N. Human Rights Council have identified what it said were war crimes and crimes against humanity committed by Israel and Palestinian armed groups in the Gaza war. A report released last year found signs that participants in the Oct. 7 Hamas-led attack on Israel committed sexual violence in multiple locations and said that some hostages held in the Gaza Strip had been subjected to rape and sexual torture.

Although the commission said in its new report that Israel had carried out two categories of genocidal acts, it stopped short of concluding that Israel had committed genocide, a determination that requires a higher standard of proof of intent.

The committee has no legal standing. But Mr. Sidoti said that its findings would help inform the deliberations of the International Court of Justice, which is considering a South African case accusing Israel of genocide, and the International Criminal Court, which in November issued warrants for the arrest of Prime Minister Benjamin Netanyahu and the former defense minister, Yoav Gallant, over alleged war crimes in Gaza.

Israel denies that it has committed genocide in Gaza, characterizing the claim as a perversion of history.

The reports may also form part of the evidence presented in a number of cases brought in national courts or under universal jurisdiction considering the legality of providing arms to Israel, Mr. Sidoti said.

Aaron Boxerman in Jerusalem contributed reporting.

In the weeks after President Emmanuel Macron called a snap election last summer that resulted in a deeply divided French Parliament, if his name came up it was often to call for his resignation.

The unpopular president, long derided by critics as aloof, all-controlling and arrogant, looked certain to ride out the final three years of his term as a lame duck atop an unstable government of his own creation, with a rotating cast of prime ministers, and little to show for it.

But President Trump has changed that. The American leader has abruptly reversed 80 years of friendly policy toward Europe, withdrawing support for Ukraine and siding with Russia, leaving European leaders panicked and lost. In doing so, he has made this Mr. Macron’s moment.

The French president, who once seemed on the verge of disappearing, is now in the headlines daily. Mr. Macron has gathered European leaders repeatedly in Paris, rushed to Washington and later to London, and generally become the focal point of Europe’s struggling effort to stand on its own feet.

After years of warning of the “imminent brain death” of NATO, Mr. Macron’s admonition now seems prescient as Mr. Trump threatens to turn his back on the alliance.

Mr. Macron’s talk of European boots on the ground to help keep the peace in Ukraine, rejected not long ago as impossible by incredulous allies, is now a plan being worked through as a plausible way to stem the fighting.

Similarly, Mr. Macron’s vision of a Europe with “strategic autonomy” from the United States was once largely dismissed as a distant idea from a man more prone to sweeping statements than follow through. The Russian invasion of Ukraine has since caused him to put more emphasis on a “European pillar” within NATO. But other European leaders seem ready to follow him toward the goal of allowing Europeans to better defend themselves.

“Crises are very good for a president. They put them back in the center,” said Vincent Martigny, a professor of political science at the University of Nice, Côte d’Azur.

In addition, he said, “Macron is the only one who can be the leader.”

Germany’s next likely chancellor, Friedrich Merz, has yet to form a government. Though the crisis has pushed Prime Minister Keir Starmer of Britain closer to the European Union, his country is no longer an E.U. member. And it is not clear that the efforts by Prime Minister Giorgia Meloni of Italy to mediate tensions with European allies particularly interest Mr. Trump.

So Mr. Macron has stepped into the leadership vacuum.

After Vice President JD Vance castigated European leaders during his speech at the Munich Security Conference last month, signaling the American president’s radical shift in foreign alliances, the French president and his office sprang into action.

Mr. Macron called a first meeting of European leaders in Paris almost immediately after the conference ended, followed by a second one the next day. He was the first European leader to go to Washington to speak directly to Mr. Trump, briefing his fellow European Union colleagues on the meeting afterward.

A few days after a disastrous visit to the White House by the Ukrainian president, Volodymyr Zelensky, both Mr. Macron and Mr. Starmer coached their ally on how to repair the situation.

According to a French diplomat close to Mr. Macron, the French president speaks to Mr. Trump every second day, on average, and to Mr. Zelensky and Mr. Starmer even more regularly.

The path forward for Europe now appears to follow much the course Mr. Macron has pointed to for years.

In recent days, his once distant-seeming plan for European troops to enforce any peace deal between Russia and Ukraine has begun to take more solid form. Britain and France have already committed troops, and, the Danish foreign minister, Lars Lokke Rasmussen, said on Monday that his country was also prepared to take part.

On Tuesday, Mr. Macron welcomed military leaders from some 30 countries who gathered in Paris for a defense and security conference, to solicit further commitments.

One of Mr. Macron’s boldest gestures has been to open discussions with European leaders about sharing the protection of France’s nuclear arsenal with them. Besides Russia, France and Britain are the only two countries in Europe with nuclear weapons.

The suggestion spoke to the leadership status Mr. Macron wants for France, a country that has long prided itself on the independence of its nuclear arsenal.

But it also reflects the new distrust of the American commitment to European allies, and Mr. Macron’s conviction that Russia’s aggression would expand farther if left unchecked without the promise of nuclear protection.

“We are entering a new era,” he said during a televised speech at the top of the French news last week. “Peace is no longer guaranteed on our continent.”

He added, “I want to believe the United States will remain by our side, but we must be ready if that doesn’t happen.”

Yet it remains far from certain whether any of Mr. Macron’s frantic action will prove successful. Ukraine has said it would be open to a cease-fire with Russia, and Moscow responded on Thursday by saying that it, too, was open, though more discussion was needed.

Mr. Trump’s own position has been mercurial, both badgering Europe to spend on its own defense and, on Thursday, threatening it with a 200 percent tariff on wine and alcohol.

Mr. Macron’s presumption of European leadership has also at times irritated some allies. During a call to debrief his fellow European leaders about his trip to Washington, Ms. Meloni of Italy challenged Mr. Macron about in what capacity he had gone to the White House, according to people familiar with the call.

Italy’s defense minister, Guido Crosetto, accused Mr. Macron of offering European troops to Ukraine without having “the decency” to consult other E.U. countries.

“You don’t send troops like you send a fax,” Mr. Crosetto, whose government has opposed deploying troops to Ukraine, wrote on X, the social media platform.

Then there are all the practical issues, of how Mr. Macron will fund such a spending increase while France is facing a budgetary crisis.

He has prepared his country for the threat of war, announcing an increase of military spending over the next five years — with no additional taxes, he promised — and an expansion of weapons manufacturing. After the United States, France is the second biggest arms exporter in the world.

Other European countries, too, have announced that they will increase their military spending, potentially aided by proposals from the European Commission, including a €150 billion, about $164 billion, loan program to pay for more weapons and technology.

But the larger existential crisis has eclipsed all finnicky practicalities for the moment. In France, recent polls show the president’s approval rating is up from 4 to 7 points to the high 20s and low 30s — the biggest jump since the arrival of Covid in 2020, according to the monthly barometer by the French Institute of Public Opinion.

The French populace largely agree with him — that Europe must continue to support Ukraine and invest more in its own defense against a potential Russian threat, and that the United States can no longer been seen as a dependable ally.

Even many of the president’s political opponents have praised his diplomatic efforts and agreed with his analysis.

“I’m not a Macronist at all, but he was pretty good. The important thing is to try to unite people and convince them that the situation is pretty serious and that we obviously need a national mobilization,” said Cédric Perrin, a senator with France’s Republican Party who presides over the French Senate’s foreign affairs and armed forces committee.

Rather than the man meeting the moment, it seems the moment has arrived to what Mr. Macron has been saying since soon after he was first elected in 2017, when he delivered his first long speech at the Sorbonne extolling the urgent need for Europe to step from America’s shadow.

Back then, a Czech politician, Andrej Babis, who months later became the country’s prime minister, offered a back-handed slap: “He should really concentrate on France.”

Today, many in Europe concede Mr. Macron was right all along.

“In Czechia we strongly appreciate the leadership of the president of France,” said Czech Ambassador to France, Jaroslav Kurfürst. “Emmanuel Macron has earned a lot of credibility in our part of the world.”

Reporting was contributed by Emma Bubola in Rome, and Aurelien Breeden in Paris.