President Volodymyr Zelensky of Ukraine was already facing a daunting week as foreign officials gathered in Europe for talks about his country’s future.

The Trump administration was demanding $500 billion in Ukrainian mineral rights, it canceled Ukraine’s exemption from U.S. tariffs on steel and a leading American skeptic of military assistance for Kyiv, Vice President JD Vance, was on his way to Europe for a meeting with the Ukrainian leader.

But on Wednesday, things went from bad to worse. President Trump’s defense secretary, Pete Hegseth, delivered a harsh assessment of Ukraine’s prospects in its war with Russia. Then Mr. Trump announced that he had spoken with President Vladimir V. Putin of Russia, a call Mr. Trump characterized as the opening of talks to end the war — with no clear role for Mr. Zelensky.

The phone call also spelled the end of American efforts to isolate Russia diplomatically after its full-scale invasion of Ukraine nearly three years ago.

“He’s on his heels geopolitically,” Cliff Kupchan, chairman of Eurasia Group, a risk analysis firm based in Washington, said of Mr. Zelensky.

Mr. Trump’s actions in the last two days — which also included a prisoner swap with the Kremlin that freed an American teacher — signaled a thawing relationship between the United States and Russia that could favor Mr. Putin in a peace deal while leaving Ukraine on the sidelines.

Mr. Trump also called the Ukrainian leader on Wednesday, but in a social media post he did not mention how, or if, Mr. Zelensky would figure in peace talks.

Mr. Zelensky will meet with Mr. Vance and the secretary of state, Marco Rubio, at the annual Munich Security Conference, which opens on Friday, Mr. Trump said.

Negotiations to end the deadliest war in Europe in generations will shape the future of Ukraine, and the recent developments mean some of its territory is likely to remain under Russian occupation.

And they will shape Mr. Zelensky’s political future. He has little choice but to go along with American-led talks despite his deep skepticism, shared by most Ukrainians, of Mr. Putin’s readiness to negotiate without imposing onerous conditions or bringing more military and economic pressure to bear.

By Thursday morning, it was a sentiment swirling widely in Kyiv, a city now hit nightly with Russian missiles and exploding drones.

Volodymyr Fesenko, a political analyst, wrote on Facebook that Mr. Putin was most likely playing the Trump administration for time. “He is not going to compromise on ending the war, as Trump’s team wants,” he wrote.

Mr. Trump wasn’t the only one to deliver sobering news to Ukraine. Mr. Hegseth told European allies on Wednesday that it was “unrealistic” for Ukraine to return to its borders as they were before Russia’s military invasion began in 2014.

And he added that the United States did not support Ukraine’s goal of joining NATO to secure any peace settlement, calling it “unrealistic.”

Mr. Zelensky has played weak hands well before. In the opening days of Russia’s invasion, he popped out of a bunker to film selfie videos that rallied his country, and much of the world, to Ukraine’s cause.

Now he is again facing a pivotal moment for his country in a diminished position, sinking in domestic polls and getting a cold shoulder from his most important ally.

Mr. Zelensky has twice in recent days said he is willing to negotiate with Mr. Putin if Western allies offer security guarantees in a settlement. In his nightly address to the nation Wednesday, the Ukrainian leader was conciliatory, saying he had a “good and detailed discussion” with Mr. Trump.

“We discussed many aspects — diplomatic, military, economic — and President Trump informed me of what Putin had told him,” he added. “We believe that America’s strength is sufficient to pressure Russia and Putin into peace, together with us, together with all our partners.”

Mr. Putin, for his part, has signaled that Mr. Zelensky would need to face an election at home before Russia would accept his signature on a peace deal.

The demand suggests a Russian view of a potential three-step process for negotiating a settlement to the war, according to a person who has had recent conversations about settlement scenarios with senior Russian officials.

. It envisions an initial truce and preliminary deal, followed by elections in Ukraine and only then a binding peace settlement, said the person, speaking on condition of anonymity to discuss private conversations.

There have been some bright spots for Ukraine. Soon after his inauguration, Mr. Trump criticized Mr. Putin harshly, saying he was “destroying” Russia with the war.

And while Mr. Trump’s claim on Ukraine’s minerals comes at a big cost for Kyiv, it has also been viewed by Ukrainian officials as a hopeful sign.

The talks on mineral rights, which began on Wednesday with a visit to Kyiv by the American Treasury secretary, Scott Bessent, open a path for Mr. Trump to continue military aid while claiming to have secured a benefit for the United States.

“They’ve essentially agreed to do that, so at least we don’t feel stupid,” Mr. Trump said of Ukraine’s willingness to yield its natural resources, in an interview with Fox News that aired on Monday. “Otherwise, we’re stupid. I said to them, ‘We have to get something. We cannot continue to pay this money.’ ”

That was before Russia and the United States showed a new willingness to work together. On Tuesday, Mr. Trump’s friend and envoy, Steve Witkoff, flew a private jet into Moscow to retrieve an imprisoned American teacher, Marc Fogel, a notable gesture of conciliation by Moscow. In return, the Kremlin said, the United States would deliver a Russian cybercriminal, Alexander Vinnik, back to Russia.

Mr. Zelensky has rejected Mr. Putin’s repeated claims that he is an illegitimate leader, and that Ukraine needs to lift martial law and hold elections. (Ukrainian elections were delayed under martial law after Russia invaded in 2022. Mr. Zelensky’s five-year term, which would have expired last May, was extended under the law.)

Ukrainian officials say they view the Russian demand for democratic elections as part of a ploy to destabilize the government and compel Ukraine to let its guard down for a vote. They have urged the Trump administration not to endorse the idea.

“It is the Russians who are raising the topic of elections because they need their man in Ukraine,” Mr. Zelensky said in an interview with the British broadcaster ITV News that aired last weekend. “If we suspend martial law, we may lose the army. And the Russians will be happy because the qualities of spirit and combat capability will be lost.”

Inside Ukraine, however, his domestic opponents are quietly preparing for a possible campaign.

Despite his diminished status going into talks, it is too early to write off Mr. Zelensky, a former actor and an adept leader in a crisis, Mr. Kupchan, the Eurasia analyst, said. “He’s proven to be quite a skilled counterpuncher,” he said. “I don’t feel we’re in the final act of any play yet.”

Mr. Zelensky is preparing for talks as the momentum on the main front of the war, in the Donbas region of eastern Ukraine, has favored Russia for more than a year. It is unclear for how long Russia can sustain extraordinarily high casualties, which have been estimated by military analysts as at least in the hundreds daily.

And Ukraine is entering talks with one bit of leverage: its control over a few hundred square miles of Russian territory in the Kursk region captured last summer, an incursion that was deeply embarrassing to the Kremlin. Mr. Zelensky said he wants to trade territory in Kursk for Russian-held Ukrainian land, something Mr. Putin would almost certainly resist.

If the momentum of a few dozen or hundreds of yards of advances per day continued through negotiations, it would give an advantage to Moscow. Then, any delay by Ukraine in accepting cease-fire terms would cost Kyiv territory.

Russia’s progress has, though, slowed since November in month-on-month measures of captured territory, according to the Institute for the Study of War, a U.S.-based analytical group.

In January, for example, Russia captured about 40 fewer square miles than in December, the institute reported. Military analysts have cautioned it is not possible to determine how significant that decline is.

Anton Troianovski contributed reporting.

For President Vladimir V. Putin, one phone call marked a turning point as great as any battle in his three-year war.

In a lengthy call on Wednesday, President Trump delivered a message to Mr. Putin that encapsulated much of how the Russian leader sees today’s world: that Russia and the United States are two great nations that should negotiate Ukraine’s fate directly and move on to addressing even weightier global affairs.

It was the clearest sign yet that Mr. Putin, despite Russia’s disastrous failures at the outset of his Ukraine invasion in early 2022, could still emerge from the war with a redrawn map of Europe and an expansion of Russia’s influence in it.

The call came on the same day that Mr. Trump’s defense secretary, Pete Hegseth, declared that the United States would not support Ukraine’s desire for NATO membership. It also came as the Senate confirmed Tulsi Gabbard, widely seen as sympathetic to Mr. Putin, as the next director of national intelligence.

Taken together, the developments marked a payoff for Mr. Putin’s monthslong campaign of lavishing praise on Mr. Trump — apparently in the belief that the American president has the power to deliver a Russian victory in Ukraine.

“Putin is playing a very clever game,” Tatiana Stanovaya, a senior fellow at the Carnegie Russia Eurasia Center in Berlin, said. “He’s investing 100 percent into the effort to seduce Trump.”

In Moscow, news of the long-awaited call ushered in a wave of barely contained glee. Commentators claimed that the American-led three-year effort to isolate Russia had emphatically ended. They celebrated Mr. Trump’s glowing social media post after the call about “the Great History of Our Nations” and noted that the American president had spoken to Mr. Putin before he had called President Volodymyr Zelensky of Ukraine.

One Russian lawmaker said that Mr. Putin’s call with Mr. Trump “broke the West’s blockade.” Another said that Europeans were surely reading Mr. Trump’s post about it “with horror and cannot believe their eyes.” A third said it was a “day of good news.”

In a sign of the burst of optimism, Russia’s main stock market index jumped 5 percent on Thursday morning to its highest point since last summer, and its battered currency, the ruble, gained against the dollar to its strongest level since September.

Russian businesspeople hope that a peace deal with Mr. Trump could lead to sanctions against their country being dropped. The Kremlin said that, beyond Ukraine, Mr. Trump and Mr. Putin touched on “bilateral Russian-American relations in the economic sphere.”

Not all were happy. Some Russian cheerleaders of the war grumbled on social media that a deal with the United States could sell out the soldiers on the battlefield. A pro-war blog with more than a million followers, Two Majors, quoted a fighter who said that the discussion of Wednesday’s call “demoralizes and irritates me.”

Ms. Stanovaya and many other commentators noted that Mr. Putin’s chances of getting all he wants were far from assured. In particular, while Mr. Trump appears focused on ending the fighting in Ukraine, Mr. Putin wants a broader agreement with the United States that would push back NATO and allow Russia to reclaim a sphere of influence in Europe.

“Donald Trump spoke in favor of a speedy end to hostilities,” the Kremlin said in its summary of the call, hinting at that divergence. “Vladimir Putin, for his part, mentioned the need to eliminate the root causes of the conflict.”

On the diplomatic front, Mr. Putin still faces a Europe that is predominantly arrayed against him. Senior European defense officials gathering in Brussels on Thursday showed no sign of budging from their insistence that Ukraine be at the center of any peace talks and that Europe be at the table, too.

John Healey, Britain’s defense secretary, repeated the Biden administration’s mantra that there “can be no negotiations about Ukraine without Ukraine.”

It is unclear, however, how much leverage the Europeans would have over the U.S. on Ukraine diplomacy, despite their pushback.

The call sets up a complex negotiation whose contours — and participants — are still unclear. Mr. Zelensky will try to make the case for American support in a meeting with Secretary of State Marco Rubio and Vice President JD Vance in Munich on Friday.

Mr. Putin is likely to keep the military pressure on Ukraine while appealing to Mr. Trump’s ambitions as a peacemaker. Analysts say that what Mr. Putin cares about most is not how much territory he captures in Ukraine; rather, he wants a more comprehensive deal that keeps Ukraine out of NATO, limits the size of Ukraine’s military and reduces the Western alliance’s presence across Eastern and Central Europe.

Analysts doubt that Mr. Putin will agree to stop the fighting before he receives assurances that at least some of those wider demands will be met. He is signaling confidence that Russia has the personnel, equipment and economy to outlast Ukraine on the battlefield — and that Ukraine will collapse quickly if Mr. Trump should pull his support.

“They won’t last a month if the money stops,” Mr. Putin said last month, referring to Ukraine.

Still, Mr. Putin faces his own pressures, which some analysts believe could make him amenable to a deal in which he could come down from some of his demands. Russia’s military has been suffering roughly 1,000 casualties a day, according to Western officials, and the economy risks overheating, with the central bank’s benchmark interest rate up to a sky-high 21 percent.

Ilya Grashchenkov, an analyst of Russian politics based in Moscow, said that the call with Mr. Trump made Mr. Putin’s repeated doubling down on the Ukraine war “look like a successful bet in a casino.”

Russia absorbed huge losses in Ukraine, gambling that, eventually, “the global paradigm would change” and the West would tire of supporting the country, Mr. Grashchenkov said in a phone interview. “This change has happened, and now it is unclear how this bet will play out in the future.”

Ivan Nechepurenko contributed reporting.

Not so long ago, Taiwan basked in seemingly boundless, bipartisan support in Washington, where the island has long been regarded as a valiant democratic partner against China.

Now, a few weeks into President Donald J. Trump’s second term, Taiwan is adjusting to a shift in its relationship with the United States, its primary backer — one that does not focus on shared democratic ideals, and that is more uncertain and transactional. Mr. Trump has accused Taiwan of spending far too little on its own security and of gaining an unfair dominance in making semiconductors.

Taiwanese officials and businesspeople have been trying to assure the new administration of their commitment to cooperation. They have traveled to Washington for meetings, bearing charts detailing their military outlays, and attended inauguration events filled with the MAGA faithful. They have floated new deals that Taiwanese companies could broker with American businesses in gas and other fields, and tried to explain the value of Taiwan’s semiconductor manufacturing to American interests.

Underlying their efforts is an anxiety over what Mr. Trump may do, for instance, to press Taiwanese companies to move advanced semiconductor production to the United States. Mr. Trump has said he might soon impose tariffs on semiconductors. Taiwanese officials have been preparing to help Taiwanese businesses soften the blow of any such move.

“I think Taiwan just convinced itself that they had good relations with the U.S. and they had lots of friends in Congress, and they would be able to weather the storm,” said Bonnie S. Glaser, the managing director of German Marshall Fund’s Indo-Pacific program, who often speaks with Taiwanese politicians. “When Trump made those comments, I think it was a wake up call for people in Taiwan that they really didn’t know what was coming next.”

Governments around the world are trying to adjust to Mr. Trump’s combative approach. But the stakes for Taipei are especially high. The island depends on the United States for nearly all its major weapons. It sends nearly a quarter of its exports directly to the United States, and Washington is crucial in giving Taiwan political support against Beijing, which claims that Taiwan is its territory and must accept unification — by force, if deemed necessary.

Taiwanese officials and policy advisers said the island would quickly roll out measures to help its businesses hurt by any new U.S. tariffs. They spoke on condition of anonymity because of the sensitive and provisional nature of the plans, and declined to give details. Some officials have publicly hinted at the preparations. “We’re preparing for a range of scenarios,” the minister of economic affairs, Kuo Jyh-Huei, told reporters when asked about Mr. Trump’s threatened tariffs. “If we showed our hand now, that would not work to the benefit of everyone.”

Even if Mr. Trump holds off on the tariffs, Taiwan faces more pressure from his administration on other issues. They include the island’s big trade surplus with the United States, which climbed to a record $74 billion last year according to U.S. data, and its military spending and preparations, which many in Washington see as lacking, even though billions of dollars worth of orders of American military equipment are stuck in a backlog. The United States is committed by law to help Taiwan defend itself, and leaves open the possibility of intervening militarily if China tried to conquer the island.

“There’s a basic mismatch. We’ve been thinking that America and Taiwan are in a strong partnership, but America under Trump thinks Taiwan doesn’t do enough,” said Jason Hsu, a former Taiwanese lawmaker and technology investor who is now a senior fellow at the Hudson Institute. “Sooner or later, the Taiwan government will need to show up in town with a package ready to offer Trump.”

Publicly, the Taiwanese government is projecting calm confidence about relations with Washington. But Taiwanese officials’ efforts to build bridges into Mr. Trump’s inner circle during trips to Washington last month and in December, have yielded little so far, said three American officials familiar with their attempts, who described the interactions as limited.

Taiwan sent two economic officials to Washington this week to “better explain ourselves to Mr. Trump’s circle,” Mr. Kuo, the economic affairs minister, told reporters before their departure. Taiwan also hopes to buy more liquefied natural gas from Alaska, he has said.

“Taiwan is preparing some presents for Trump,” said Jeremy Chih-Cheng Chang, the chief executive officer of the Research Institute for Democracy, Society and Emerging Technology in Taipei. “They have already indicated some, as you have seen in news reports — like buying liquefied natural gas — but there are sure to be others.”

In January, executives from Taiwan Semiconductor Manufacturing Company — TSMC, the world’s most advanced chip maker — held talks with Mr. Trump’s nominee for commerce secretary, Howard Lutnick, said several people familiar with the talks who spoke on condition of anonymity.

In December, Taiwanese officials visiting Washington showed officials and Republican politicians a presentation designed to demonstrate that Taiwan has been rapidly increasing military preparations, according to people familiar with those discussions. They met with Michael Waltz, then a Florida congressman known for being hawkish on matters of national security, according to one of the people.

Taiwanese officials remain hopeful that they will find robust supporters in two men who were deeply critical of China in Congress: Marco Rubio, the secretary of state, and Mr. Waltz, now Mr. Trump’s national security adviser. But some former officials who strongly supported Taiwan in Mr. Trump’s first term have not been brought into his new administration, including Mike Pompeo, the former secretary of state.

“It’s very telling that some hard-line hawks on Taiwan have been left out,” said Christopher K. Johnson, the president of China Strategies Group, a consulting firm, and a former U.S. government intelligence officer. “It looks like Taiwan bet on some of the wrong horses.”

Half a dozen or so officials poised to take senior positions in the Pentagon have rejected the G.O.P.’s tradition of backing an expansive foreign reach, in favor of limiting U.S. military commitments abroad. They represent an ascendant foreign policy doctrine in a party that in recent years has chafed at committing more military support to Ukraine, and pushed NATO allies to spend more on their militaries.

In an opinion essay published last May, Mr. Trump’s nominee to serve as the Pentagon’s under secretary of defense for policy, Elbridge Colby, warned that Taiwan should not assume that it was indispensable to the United States. “America has a strong interest in defending Taiwan, but Americans could survive without it,” he wrote. He and other Pentagon officials have suggested that Taiwan should increase its military spending to at least 5 percent of its economic output, or about twice what it currently is spending.

The Taiwanese government has said it is committed to expanded military spending, though many Taiwanese experts and officials, privately, question the 5 percent target. President Lai Ching-te of Taiwan also faces a legislature controlled by opposition lawmakers who have accused his government of wasteful spending and reined in parts of this year’s defense budget.

At the same time, Taiwan has its own frustrations with the United States, including the big backlog of undelivered orders of arms and military equipment to the island.

“I do sense a soreness of being told to spend more when they haven’t received what they’ve already paid for,” said Steve Yates, a senior research fellow at the Heritage Foundation, referring to Taiwan. “The U.S. has to fix its defense manufacturing supply chain before it can reasonably put pressure on others to do and buy more.”

Ana Swanson in Washington and Amy Chang Chien in Taipei contributed reporting.