Trump Victory Will Signal a Shift in Ukraine War. To What Is Unclear.

As U.S. president, Donald J. Trump will inherit a role as Ukraine’s chief benefactor. But he has been skeptical about continuing aid to Kyiv.

With Donald J. Trump’s victory in the United States presidential election, Ukrainians now face an all-but-certain American policy shift in the midst of a war that is turning against them. Russia has made some of the swiftest territorial advances in recent months, and diplomatic efforts are underway by multiple countries to find a negotiated settlement.

Mr. Trump will enter office with a record of skepticism, if not outright hostility, to continued U.S. aid to Ukraine, and he has promised that he could end the war in one day — without saying how. It is unclear how any initiative by Mr. Trump would dovetail with existing cease-fire discussions, but his pledge to bring the war to a rapid end has stirred concern in Kyiv that he will pressure Ukraine into an agreement on unfavorable terms.

“His desire for a deal — and probably a quick one — does not bode well for sustained U.S. support,” the Royal United Services Institute, an analytical group based in London, wrote on Wednesday, referring to Mr. Trump.

Russia will most likely respond to Trump’s win by pressing its advantage of numbers on the battlefield in anticipation of reduced Western support, the group said.

Ukrainska Pravda, a Ukrainian news outlet, wrote in a commentary on the American election that the war in Ukraine was less central to U.S. politics than the wars in Vietnam or Korea had been. There, “American boys fought and died,” the site noted.

Ukraine has said all year that it is prepared to work with either a Republican or Democratic administration, and in September President Volodymyr Zelensky of Ukraine met with Mr. Trump while on a visit to the United States.

Mr. Zelensky wasted no time in offering his congratulations, writing on Wednesday that he appreciated “President Trump’s commitment to the ‘peace through strength’ approach in global affairs.”

“This is exactly the principle that can practically bring just peace in Ukraine closer,” he wrote. “I am hopeful that we will put it into action together.”

After assuming the presidency, Mr. Trump will inherit the United States’ role as armorer and financier in the war against Russia. The United States is Ukraine’s single most important benefactor for military and financial support, though taken together, the countries of the European Union provide more.

Mr. Trump has not only questioned the need to continue to support Ukraine; he has also spoken admiringly of President Vladimir V. Putin of Russia, while castigating Mr. Zelensky. And Mr. Trump’s pledge to end the war in a day has raised concerns in Kyiv that he would press a peace settlement on unfavorable terms to Ukraine.

“We’ll see, but I am very skeptical that the war will end quickly, in 24 hours, as Trump promised,” a former economy minister, Tymofiy Mylovanov, wrote on Facebook. Mr. Mylovanov noted, however, that Ukrainian government bonds were expected to rise in anticipation of a negotiated settlement.

As Mr. Trump racked up the electoral votes needed to win, the war was still raging in Ukraine. Air alarms sounded in Kyiv, and Ukraine’s general staff headquarters reported that Russia had launched 71 airstrikes by 10 p.m. on Tuesday.

Ukrainian soldiers viewed the election result as yet another challenge in an increasingly difficult situation. Oksana Vedmid, 32, a private, was in a bunker with a drone unit in eastern Ukraine early Wednesday outside the city of Chasiv Yar, watching for any movement of Russian forces while also checking in on the latest election news.

“It feels like a small loss of hope for better support in our difficult struggle, knowing his stance and sympathy toward our enemies,” she said by telephone, referring to Mr. Trump. “At the same time, I understand that the situation has become so tough recently that even the aid we’ve received hasn’t been enough to improve our position.”

Lt. Pavlo Velychko, reached by phone after returning from an overnight patrol, said that the result could prompt Europe to take a larger role in defending its eastern borders and Ukraine.

“We should not hope for a miracle from across the ocean,” he said, referring to the United States. “Europe is awakening. That will be a necessary prerequisite for successfully resisting the imperial encroachment of the Russians.”

Trends on the battlefield have been bleak for months and have grown more worrying for Ukraine in recent days.

Russian advances in the eastern Donbas region, creeping at first, began to accelerate in August and have picked up since. Ukraine, short of soldiers, has resorted to shifting troops between hot spots on the front to hold the line. Early signs of an unraveling are emerging in an army that, despite the odds, had largely held off a much bigger and better-armed adversary for more than two years.

The shuffle of soldiers has opened other sectors to attack. As positions fail or are at risk, soldiers are rushed from elsewhere to reinforce the lines, only for Russia to attack or menace the vacated sites.

Mobilization in Ukraine, which picked up over the summer with men being pulled from rock concerts or out of cars at roadblocks, has tapered amid deep reluctance to fight in the trenches, military analysts say. Desertion is a mounting problem. From January to September, Ukrainian prosecutors recorded about 51,000 cases of soldiers being away without leave, more than double the number who deserted the previous year.

Some of the army’s best troops were committed in August to an attack into the Kursk region of Russia in the hopes of diverting Moscow’s soldiers. But Ukraine has since lost about 40 percent of the territory it occupied there, and Moscow did not redeploy troops from the Donbas.

Russia has also honed its tactics for a grinding, methodical advance pushing through Ukrainian lines with infantry attacks. Battlefield maps in recent weeks have shown multiple, horseshoe-shape curves along the front as Russia sets up its troops to encircle Ukrainian positions.

Another risk looms as North Korean soldiers enter the war to aid Moscow’s efforts. Those soldiers have now joined the fight, according to U.S. and Ukrainian intelligence agencies, raising the specter of a surge in soldiers on the Russian side, though the numbers now deployed are not considered decisive.

Mr. Zelensky said on Monday that 11,000 North Koreans were already in the Kursk region of Russia.

The wobbly military picture for Ukraine clouds the prospects for a negotiated settlement. Mr. Trump has not said on what terms he would negotiate a halt in hostilities.

Delicate, multiparty talks are already underway and have gained some traction in recent months. It is unclear how a role for Mr. Trump in mediating would combine with those efforts, according to diplomats involved in the talks, who spoke on the condition of anonymity to discuss the efforts.

Short of an overall cease-fire, Mr. Zelensky has nodded in recent comments to the prospect of side deals to tackle specific issues, like a moratorium by both militaries on strikes on energy infrastructure and an agreement to safeguard commercial shipping in the Black Sea. Russia has been bombarding Ukrainian electrical infrastructure, and Ukraine has been striking at Russian oil refineries with a fleet of domestically produced, long-range drones.

Ukraine has in recent weeks also softened its stance toward a Brazilian and Chinese plan that Mr. Zelensky had initially dismissed as serving Russia’s interests.

A so-far-quiet diplomatic effort is underway to align that plan with Ukraine’s own 10-point proposal for negotiations, the officials familiar with the talks said. In the most recent movement on Ukraine’s plan, Canada last week hosted a conference on prisoner exchanges and on returning Ukrainian children abducted by Russia, one of the points in Ukraine’s plan.

Frustration with the United States has run deep among military units and in Kyiv over the slow deliveries of arms and restrictions prohibiting their use on targets inside Russia, other than along a narrow belt on the border. The current policies have led only to a losing situation on the front, according to Ukrainian officials, military analysts and diplomats.

Given all of the turns in the war, some Ukrainians took the news of Mr. Trump’s win in stride. “I am sure that it is overblown how important the elections are for Ukraine,” said Natalia Chepeliuk, 43, the director of a restaurant in Kyiv. “We still need to fight for our country no matter who is the U.S. president.”

Maria Varenikova, Liubov Sholudko and Nataliia Novosolova contributed reporting.

Our Coverage of the War in Ukraine

• Incendiary Devices on Cargo Planes: Western officials are investigating whether devices planted at shipping hubs in Europe may have been a test run by Russian operatives for placing them on planes bound for the U.S.
• Pessimism Reigns in Russia Over U.S. Election: Russian officials feel disrespected by the Democrats and betrayed by Donald Trump, who lavished praise on President Vladimir Putin but made decisions the Kremlin saw as benefiting Ukraine.
• U.S. Fears a Grim Phase: American military and intelligence officials have concluded that the war in Ukraine is no longer a stalemate as Russia makes steady gains, and the sense of pessimism in Kyiv and Washington is deepening.

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