After Moscow and Washington danced around the issue of a summit for the better part of seven months, President Trump said on Friday that he would meet next Friday with President Vladimir V. Putin of Russia to discuss an end to the war in Ukraine.

Mr. Trump announced on social media that the two leaders would meet in Alaska, without immediately providing any other details. Given that the meeting will not involve Ukraine, chances of any immediate breakthrough are considered slim.

Still, a summit would represent a marked change in U.S. policy. The West has treated Mr. Putin largely as a pariah since he invaded Ukraine in 2022, causing hundreds of thousands of deaths and widespread destruction for both countries. The mere fact that an American president is willing to meet with him is considered a diplomatic victory for the Kremlin.

Alaska was part of the Russian Empire until 1867, when Czar Alexander II, staggering under war debts, sold it to the United States for $7.2 million.

Why is the summit happening now?

Ever since Mr. Trump took office in January, the United States and Russia have repeatedly raised the possibility of a summit between the American president and Mr. Putin.

While the Russian leader has been eager for a meeting, Mr. Putin balked at taking any concrete steps toward ending the war while he believed that Russia was advancing into Ukraine.

Mr. Trump, initially supportive of Russia and critical of U.S. military aid to Ukraine, repeatedly held off on a meeting while ending the war appeared impossible. He repeatedly expressed his frustration. Then he had made Friday the deadline for imposing new sanctions unless Mr. Putin ended the war.

Mr. Trump made good in part on those threats on Thursday, raising tariffs on Indian imports to the United States to 50 percent to penalize it for continued imports of Russian oil.

The Russian request for a summit came just as the deadline loomed for Mr. Trump’s new primary and secondary sanctions. Word of the meeting emerged soon after Steve Witkoff, Mr. Trump’s special envoy, held a meeting with Mr. Putin in the Kremlin on Wednesday, although neither side has detailed what was said.

What does Putin want from a summit?

It is possible that Mr. Putin is using the summit as another stalling tactic, as well as a way to try to improve frayed ties with Washington.

On a larger scale, the summit corresponds to Mr. Putin’s worldview, that great powers should determine their own spheres of influence, much the way that Stalin met with President Franklin D. Roosevelt and Prime Minister Winston Churchill of Britain in Yalta in 1945 to carve up postwar Europe.

Mr. Putin believes that Russia’s vast nuclear arsenal still makes it a world power, even though Russia produces very little that the rest of the world wants apart from energy.

Mr. Putin, having called the 1991 breakup of the Soviet Union “the greatest geopolitical catastrophe of the century,” has sought for decades to reassert Moscow’s control over Ukraine.

Russia and Ukraine have held three rounds of talks in Istanbul, and Moscow has used those meeting to try to achieve what it has been unable to win on the battlefield.

Mr. Putin will most likely make the same maximalist demands at any meeting with Mr. Trump: claiming eastern Ukraine as Russian; keeping Ukraine out of NATO; preventing the alliance from expanding into former Soviet realms; limiting the size of Ukraine’s military and ensuring that its government is friendly toward Moscow.

What’s at stake for Trump?

One of Mr. Trump’s campaign promises was to end the war in Ukraine in 24 hours. That deadline has long past, but he still considers himself a supreme deal maker. He has also made no secret of wanting a Nobel Peace Prize, and has linked his deserving of the prize to his efforts in Ukraine, among other conflicts.

His position on the war has been volatile. Earlier this year, he seemed to align himself with the Kremlin, limiting military aid to Ukraine for a time and browbeating President Volodymyr Zelensky during a notorious Oval Office meeting in February.

But as his frustration with Mr. Putin grew, he recently authorized more arms sales intended for Ukraine. He criticized Russia’s bombardment of Ukrainian cities as both “disgraceful” and “disgusting.” And a month ago, he directly criticized Mr. Putin.

“We get a lot of bullshit thrown at us by Putin, if you want to know the truth,” Mr. Trump told reporters during a cabinet meeting. “He’s very nice to us all the time, but it turns out to be meaningless.”

This week, the American president has been back on the peace theme. “Everyone agrees this War must come to a close, and we will work towards that in the days and weeks to come,” Mr. Trump wrote on his social media platform.

What leverage does the U.S. have over Russia?

Although Mr. Trump has threatened severe direct and secondary sanctions against Russia in order to try to end the war, he has conceded that they might not have any effect.

While previous American presidents might have agreed to a summit as a reward for concessions toward a peace deal, there is no sign that Mr. Putin has changed his attitude toward rejecting any such outcome.

Continued energy sales have allowed Russia to endure the toughest Western sanctions imposed thus far, and the country has minimal direct trade with the United States. Mr. Trump has not imposed the sharp tariffs on Russian imports levied against some American trading partners.

Mr. Trump said in an interview with CNBC on Tuesday that “Putin will stop killing people if you get energy down another $10 a barrel.” But Mr. Trump has not moved to sanction China, the largest importer of Russian oil, and Indian officials have said they intend to continue buying Russian oil.

Could the summit achieve a breakthrough?

One of the main actors in Russia’s war on Ukraine, namely Ukraine, will not be represented at the summit. Mr. Trump has said that he will meet with Mr. Zelensky soon afterward, but that absence has already limited the outcome. Europe, which also has a large stake in the outcome of the war, will also not be represented.

Despite the enormous toll that the war has taken on Ukraine in death and destruction, polls indicate that a solid majority of Ukrainians reject the idea of making the territorial and other concessions demanded by the Kremlin.

The refusal by both sides to make concessions has long stymied any effort at a negotiated settlement, and there are few signs of optimism now.

“Is it a real shift in the resolution of the Ukraine conflict?” wrote a Russian tabloid, Moskovsky Komsomolets, about the summit. “Or will it again turn out to be a false start, hype and confusion?”

Some Ukrainian soldiers expressed similar sentiments.