In comments that stunned America’s allies in Europe and angered Ukraine’s government, President Trump on Tuesday appeared to blame Ukraine’s leaders for Russia’s invasion.

He also suggested that they do not deserve a seat at the table for the peace talks that he has initiated with President Vladimir V. Putin of Russia.

“You should have never started it,” Mr. Trump said, referring to Ukraine’s leaders. “You could have made a deal.” He followed up on Wednesday in a post on social media, calling Ukraine’s president, Volodymyr Zelensky, a “dictator without elections” and saying he had “done a terrible job” in office.

Here’s a look at how the war began, the state of the peace talks and Ukraine’s election record.

What caused the war in Ukraine?

There is no doubt that Russia started the war by invading Ukraine. Russian troops stormed over the border almost exactly three years ago, with the explicit aim of toppling the pro-Western government of Mr. Zelensky in Kyiv, the capital. Russia’s military attacked from the east and north, including from Belarus, as well as from the Russian-occupied southern province of Crimea. That attack started the biggest conflict in Europe since World War II.

Leaders around the world, including former President Joseph R. Biden Jr., denounced Russia’s invasion as an act of unprovoked aggression against a sovereign state, and the U.N. General Assembly passed a resolution calling for Russia’s immediate withdrawal. Since then, Russian firepower has leveled whole cities and killed more than 12,000 Ukrainian civilians, according to the United Nations.

Hundreds of thousands of soldiers have also been killed and wounded, and Russian soldiers have committed a series of atrocities, not least in the city of Bucha, north of Kyiv. The Kremlin has said its soldiers do not commit war crimes.

The International Criminal Court has also accused Mr. Putin of war crimes in Ukraine and issued a warrant for his arrest, along with another senior Russian official. Last year it also issued warrants for the arrest of two Russian commanders.

Mr. Putin and the Kremlin have referred to the invasion as a “special military operation,” avoiding the term “war,” and he has said he sought to demilitarize but not occupy Ukraine. He put forward several explanations for the move, saying that in part he was acting to protect civilians in Ukraine’s east.

He also characterized the invasion as a last-ditch effort to thwart what he called the West’s expansion toward Russia’s borders. The enlargement of the NATO military alliance to incorporate countries in Eastern Europe since the end of the Cold War, he claimed, was effectively a plot to destroy Russia.

And Mr. Putin said that Russia, and specifically the Bolshevik revolutionary leader Vladimir Lenin, created modern Ukraine, a position historians deride as false. Ukrainians voted in 1991 in a democratic referendum to leave the Soviet Union. Mr. Putin also said that the invasion aimed to demilitarize Ukraine and combat “Nazis,” an apparent reference to far-right parties and elements of the Ukrainian Army. Far-right parties won about 2 percent of the vote in the country’s 2019 election. Mr. Zelensky, who is Jewish, signed a law several months before the invasion combating antisemitism.

In a speech on the war’s first day, Mr. Zelensky vowed that his country would resist Russian aggression and framed Moscow’s invasion as an attack on freedom itself. “Putin began a war against Ukraine, and against the entire democratic world,” he said. Since then, Mr. Zelensky has repeatedly said that Ukraine stood as Europe’s first line of defense against Russian encroachment.

Before the full-scale invasion, Russia seized the Ukrainian province of Crimea, which it annexed illegally in 2014, and also took territory in the eastern Donbas region, including the provincial capitals of Donetsk and Luhansk.

What is happening on the battlefield?

In all, Russia now occupies around 20 percent of Ukraine, but so far it has failed in its key objectives of breaking Ukraine’s military and securing Kyiv. The fighting is largely confined to a front line in the east and south of the country, with Russian forces creeping forward amid heavy losses.

Last August, Ukraine launched a surprise incursion into the Russian region of Kursk, where Russian forces assisted by soldiers from North Korea have been fighting back.

Military experts say that in the immediate term, Ukraine has little chance of recapturing its lost territory, particularly if the United States slows or stops the flow of military aid.

What has happened in the peace talks so far?

Representatives of Ukraine and Russia held talks in the weeks after the start of the war in 2022 but failed to reach a cease-fire agreement. Since then, Ukraine has tried to gain international support for its own 10-point Peace Formula, which demands a full withdrawal of Russian forces, the prosecution of war crimes and the payment of reparations.

The prospect of peace talks, however, has gathered pace since President Trump’s inauguration last month. Mr. Trump held a lengthy call with Mr. Putin last week, which blindsided Ukraine’s government and allies in Europe and suggested that the two men intended to negotiate Ukraine’s fate directly without their involvement, a priority for the Kremlin.

In a major change from former President Biden’s policy that Ukraine would decide whether to make concessions in exchange for peace, the U.S. defense secretary, Pete Hegseth, said that it was unrealistic for Ukraine to regain the territory it held before Russia’s 2014 invasion, and that Mr. Trump did not support Ukraine’s entry into NATO. In a further blow to Ukraine, Mr. Hegseth said that after a peace deal, the responsibility for guaranteeing the country’s security would fall mainly on European countries rather than on NATO.

At a meeting in Saudi Arabia on Tuesday, Secretary of State Marco Rubio and Sergey V. Lavrov, Russia’s foreign minister, agreed to reset their countries’ relationship and to work on a peace plan for Ukraine. Mr. Zelensky, who was not invited to the meeting, sharply criticized it and said his country would “never” accept a peace deal if Ukraine did not have a seat at the negotiating table.

Why haven’t elections been held in Ukraine?

The Kremlin has called Mr. Zelensky an illegitimate leader because his five-year term has elapsed. Elections in Ukraine were suspended under martial law after Russia’s invasion, with frontline towns and cities governed solely by military administrations.

Mr. Trump also appeared to cast doubt on Mr. Zelensky’s legitimacy as president on Tuesday, and appeared to use that doubt to justify not inviting the Ukrainian leader to peace talks. “I would say that when they want a seat at the table, you could say the people have to — wouldn’t the people of Ukraine have to say, like, you know, it’s been a long time since we had an election?” Mr. Trump said. “That’s not a Russia thing. That’s something coming from me and coming from many other countries also.”

Mr. Trump also said Mr. Zelensky was “down at 4 percent in approval rating.” Although Mr. Zelensky’s approval rating has fallen from once-lofty heights, it is at around 50 percent in recent polls, not too far from Mr. Trump’s rating.

Mr. Zelensky became president after winning an election in 2019 by a landslide. A fresh election was due in 2024, but under the country’s constitution, it cannot be held while martial law is in force. Holding an election would also be a logistical nightmare, as Russian missiles rain down on the country and fighting rages.

Election experts say that any vote held during wartime would effectively disenfranchise citizens living in Russian-occupied areas, those who have fled the country as refugees and soldiers in combat.

However, internal political tensions over the use of martial law have been rising, and the mayor of Kyiv is among the officials who have accused the president’s office of abusing its powers. At the same time, Ukraine’s leaders have been under pressure from their allies over the issue, not least as part of wider efforts to demonstrate good governance.

Nataliia Klymyuk, who has been volunteering for 11 years to look after a memorial to war dead in Kyiv, the Ukrainian capital, said she had never had any illusions about President Trump.

On Wednesday, she stood among a crowd of people at the memorial, on Independence Square in central Kyiv, where tens of thousands of little flags fluttered, each representing a soldier killed during Russia’s relentless invasion. The mood was especially somber.

A day earlier, Mr. Trump, from his Mar-a-Lago estate in Florida, had blamed Ukraine for the violence. “You should have never started it,” he said, referring to Ukrainian leaders who did not, in fact, start the war.

His comment stunned many Ukrainians, who saw it as a blatant betrayal.

“I don’t believe in negotiations,” said Ms. Klymyuk, 51, who plants new flags at the site daily and clears away snow. Referring to President Vladimir V. Putin of Russia and President Volodymyr Zelensky of Ukraine, she added: “Trump has always been a friend to Putin, and I don’t believe that he suddenly became our friend. He is only pursuing his own interests behind Zelensky’s back.”

Marina Ivashyna, 30, who was passing through the square, said that her father had died in the war and that her husband was missing in action. “It is tough for me — I don’t believe anything good will happen,” she said, bursting into tears. “I don’t believe in these negotiations.”

Ms. Klymyuk’s and Ms. Ivashyna’s refrain represents a growing sentiment in Ukraine as the United States and Russia have moved toward a head-spinning reset of their relationship that could disadvantage Ukraine in the war. Ukrainians are becoming disillusioned with the Trump administration, many analysts say.

In December, a large percentage of Ukrainians said they trusted Mr. Trump, who was then the president-elect. On Wednesday, expressions of disappointment and even rage were everywhere: from the front in the east to the streets of Kyiv, from social media to the halls of government buildings.

“Many people were tired of Biden’s indecisiveness and had hopes that Trump would be able to force Russia to end the war, and we can see that they are now disappointed,” said Oleh Saakyan, a political analyst and co-founder of the National Platform for Resilience and Social Cohesion, a Ukrainian think tank.

In his news conference on Tuesday, Mr. Trump also denigrated Mr. Zelensky and suggested that new elections in Ukraine should play a part in the country’s negotiations with Russia. He deepened his criticism on Wednesday, calling Mr. Zelensky a “dictator” who took money from the United States to go to war with Russia.

“Ukrainians might not like their government, but they are fanatically devoted to the value of freedom of choice,” Mr. Saakyan said. “People in Ukraine get angry when freedom of choice is taken away from them, and that’s exactly what Trump did when he started dictating to Ukrainians that they need elections.”

A 36-year-old special operations soldier fighting in eastern Ukraine, who asked to be identified only by his call sign, Cap, for security reasons, went a step further. “I can be blunt: Trump is like Putin,” he said. “He’ll never tell the truth and will make up whatever he wants.” He added that Ukraine should not rely on Mr. Trump.

“Whenever soldiers hear what Trump is saying, it gives them a nervous twitch,” he said.

Yulia Hrebnyeva, a member of the City Council in the northern Ukrainian city of Chernihiv, said she had “no understanding whatsoever” of Mr. Trump’s speech on Tuesday, with its echoes of Russian propaganda.

“We were expecting from him actions that could help us win, not that he would just sit and talk with our enemy,” she said. Early in the invasion, Ms. Hrebnyeva’s house was hit by a falling Russian fighter jet. At the time, she was hiding in the basement with her children.

For many, Mr. Trump’s news conference on Tuesday was a moment of truth. They hoped he would uphold the United States’ commitment to Ukraine’s war effort. Instead, the president blamed Ukraine for the war and made several false claims, including that Mr. Zelensky had an approval rating of just 4 percent. In fact, recent polls put his approval rating between 42 and 57 percent.

For other Ukrainians, their confidence in the United States had already buckled over the weekend when it became clear that peace talks with Russia would begin without Ukrainian participation.

“Goodbye America,” Yevhen Dykyi, a political analyst and Ukrainian veteran, wrote on Facebook. “We must accept the reality that we no longer have an ally on the other side of the Atlantic.”

Even opponents of Mr. Zelensky have been angered by Mr. Trump’s comments. Oleksandr Notevskyi, an analyst at the Center for Policy Formation and a vocal critic of the Ukrainian president, lashed out at Mr. Trump for interfering in Ukraine’s domestic politics.

As much as he hoped that another leader would soon replace Mr. Zelensky, Mr. Notevskyi said, he believed strongly that such decisions should be made only by the Ukrainian people. Foreign criticism like Mr. Trump’s, Mr. Notevskyi said on social media, was not just “an attack on Volodymyr Zelensky.”

“It’s an attack on the President of Ukraine, on our sovereign government, and on the Ukrainian state,” he wrote.

“The most important trait of Ukrainians is our ability to unite under pressure and defend our choice,” Mr. Notevskyi later said in an interview. “The vibes are the same. But this time, the target of our rage will be someone else. No one will impose anything on us.”

Ukrainians worry that they have lost the United States as an ally.

“Several factors indicate that the U.S. is no longer a key partner for Ukraine,” said Mariia Zolkina, a Ukrainian political analyst at the London School of Economics. “Even before the start of the negotiations, Trump sacrificed those positions that were fundamental for Ukraine,” including NATO membership and control of territory. Mr. Trump, she said, “gave carte blanche to the occupation.”

Ihor Lachenkov, a Ukrainian civil activist and volunteer, wrote an angry post on Facebook criticizing Mr. Trump’s assertion that Mr. Zelensky could have negotiated. “I am so sick of all this,” he said. “Of course, it’s the bad Ukrainians who just refused to surrender and give up,” he added sarcastically.

Soldiers are also monitoring Mr. Trump’s speeches. His latest comments have left many enraged.

But a soldier from the 82nd Air Assault Brigade, who asked to not be identified as he was not authorized to speak to the news media, said Mr. Trump’s statements would not deter him and his friends.

“The primary task of the 82nd Air Assault Brigade is to liberate Ukrainian territory from occupiers and defend our country,” he said. “We will continue doing that, regardless of Trump’s statements.”

Oleksandr Merezhko, a member of Ukraine’s Parliament from Mr. Zelensky’s party and chairman of the Foreign Affairs Committee, said that despite Mr. Trump’s words it was important for Ukraine to remain in dialogue with the United States. “The situation is difficult, but not hopeless,” he said. “Trump himself gives advice in such situations: Never give up!”

Oleksandra Mykolyshyn contributed reporting from Kyiv and Yurii Shyvala from Lviv, Ukraine.

At the nation’s borders, federal workers keep the country safe in many ways: Some investigate sick passengers. Some examine animals for dangerous pathogens. And some inspect plants for infestations that could spread in this country.

Late last week, the Trump administration dispatched hundreds of those federal employees with the same message that colleagues at other agencies received: Their services were no longer needed.

The absence of these federal officers at the borders leaves Americans vulnerable to pathogens carried by plants, animals and people, experts warned.

The firings come even as the Trump administration is said to be readying plans to turn back migrants on the grounds that they might bring diseases like tuberculosis and measles into the country.

“Screening for communicable diseases at ports of entry is an important role of public health in order to prevent communicable diseases from entering our country,” said Dr. Carlos del Rio, an infectious disease physician at Emory University.

“Not having public health employees to do this job is concerning and makes us less safe,” he added.

The Centers for Disease Control and Prevention estimates that every day, nearly 30,000 planes travel in and out of the country. In 2019, more than 400 million travelers arrived via more than 300 ports of entry. About half of those people crossed the border between the United States and Mexico.

Border posts are manned by workers from multiple agencies. Employees from the C.D.C.’s Division of Global Migration Health screen people, animals and animal products for diseases, respond to reports of ill travelers and distribute medications as needed.

The Trump administration last week dismissed an unknown number of people from the C.D.C.’s 20 port health stations, leaving some entirely unattended, according to three officials with knowledge of the situation.

Calls to the port station in San Juan, P.R., on Wednesday, for example, were rerouted to the station in Miami, where a C.D.C. employee who declined to be identified said that no one would be at the San Juan post “for a very long time.”

Other port stations are in Anchorage, Atlanta, Chicago, New York, San Francisco and three cities in Texas.

C.D.C. officers can legally detain or conditionally release people and wildlife suspected of carrying any disease on a long list that includes measles, tuberculosis, pandemic influenza and viral hemorrhagic fevers such as Ebola and Marburg.

The Department of Agriculture employs entomologists, botanists and mycologists — experts in insects, plants and fungi, respectively — who inspect agricultural products for pests and pathogens. Many of those specialists were also let go on Friday.

“We’re such a critical program, it makes no sense,” said one U.S.D.A. official with knowledge of the situation, who asked not to be named for fear of retaliation.

“If we don’t work and those inspections don’t happen, things start piling up at the ports,” the official added.

Animal health experts have been particularly concerned about African swine fever and New World screwworm, two diseases that have been creeping closer to the United States and could have devastating impacts on the pork and beef industries.

On Tuesday, the U.S.D.A. said it had mistakenly fired several employees working on the country’s bird flu outbreak and was trying to hire them back, according to a report by NBC News. It’s unclear how many of the employees have returned to their positions.

Trump and Zelensky traded blows in an escalating feud

President Trump yesterday called Ukraine’s president, Volodymyr Zelensky, a “dictator” who took money from the U.S. to go to war with Russia. In a social media post littered with falsehoods, Trump didn’t mention President Vladimir Putin, or that Russia seized some Ukrainian territory in 2014 before its full-scale invasion in 2022.

Trump also suggested that the future security of Ukraine would not be an American problem.

“This War is far more important to Europe than it is to us,” he wrote on Truth Social. “We have a big, beautiful Ocean as separation.”

The feud began after White House and Kremlin officials in Saudi Arabia began peace talks that excluded Ukraine. After that meeting on Tuesday, Trump suggested that Ukraine had started the war. Afterward, Zelensky said Trump had been “caught in a web of disinformation.”

E.U.: Leaders met yesterday for a second emergency meeting seeking to recalibrate relations with the U.S. as Trump moved closer to Russia.

Arab leaders are working on a proposal for Gaza’s future

Envoys from five Arab countries are set to meet in Saudi Arabia tomorrow to begin fleshing out a vision for Gaza. They’re expected to meet again at a bigger summit on March 4 in Cairo.

Egypt, Jordan, Saudi Arabia, Qatar and the United Arab Emirates hope that countries in the region will help fund and oversee Gaza’s reconstruction, while keeping its residents in place and preserving the possibility of a Palestinian state, according to diplomats and officials. But Israeli leaders oppose postwar plans that would pave the way to Palestinian sovereignty.

What’s next: Egypt will likely propose a committee of Palestinian technocrats and community leaders, all unaffiliated with Hamas, who could run Gaza after the war, according to two Arab diplomats and two Western officials.

Hostages: Israelis are waiting anxiously for the expected release tomorrow of the bodies of four captives held by Hamas.

Israel: A military prosecutor charged five reservist soldiers with abuse of a Palestinian detainee.

Trump Media sued a judge in Brazil

President Trump’s media company sued a Brazilian Supreme Court justice yesterday, accusing him of illegally censoring right-wing voices on social media. Hours earlier, the judge had received an indictment that would force him to decide whether to order the arrest of Jair Bolsonaro, the former Brazilian president.

Context: Bolsonaro was indicted on Tuesday on charges that he plotted a coup after losing the 2022 election, including by participating in plans to assassinate the justice. Bolsonaro had called on Trump to take action against the justice in an interview with The Times last month.

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