Davos is coming just in time for the inauguration of Donald J. Trump 2.0, and Europe is anxious. Mr. Trump is like an asteroid heading for Earth, argues Hubert Védrine, a former French foreign minister, and debates about the impact will dominate the cozy, internationalist bubble that gathers each year in the pricey snow of the Swiss Alps.

Mr. Trump talks variously about huge new tariffs, about seizing Canada, Greenland and the Panama Canal, about tying American involvement in European defense not only to Europeans increasing their military spending but also decreasing their trade surplus with the United States.

Mr. Védrine and other analysts caution that Mr. Trump likes to talk big and then bargain, and that threats and issues come and go. As his former national security adviser, John Bolton once told USA Today, working in Mr. Trump’s White House was “like living in a pinball machine,” as Mr. Trump careened from one issue to another.

But one of the dominant topics in Davos is likely to be Ukraine. Mr. Trump says he wants to end the war in a day, which virtually no one takes literally, not even his special adviser for Ukraine, Keith Kellogg. Mr. Trump or no, Ukraine is slowly losing the war, and negotiations are coming to try to end the bloodshed, probably this spring.

But on what basis is the key question. President Vladimir V. Putin of Russia is facing high inflation and interest rates but has put his country on a wartime economy in what he presents as an existential conflict with the West. Despite very high casualties, he is so far able to replenish his losses with major financial incentives: 70 percent of his forces are contract soldiers and only 7 percent are draftees, said Zaki Laïdi, a French analyst who advised the European Union’s former foreign policy chief, Josep Borrell Fontelles.

Mr. Putin believes that he is winning the war and that Western resolve to keep supporting Ukraine at such high economic cost, with so little Ukrainian progress in the trenches, is waning, argues Liana Fix of the Council on Foreign Relations in Washington. So even if Mr. Putin agrees to a request or even a demand from Mr. Trump to enter negotiations, he is considered unlikely to agree to an unconditional cease-fire and will insist on stiff terms to end the war.

In his regular year-end news conference and television spectacular, Mr. Putin repeated his contention that Ukraine is not really an independent state. Any negotiations, he said, would start from “the current realities on the ground” and be based on Russia’s position in talks with the Ukrainians in Istanbul in 2022: that Ukraine agree to abandon its NATO aspirations and become a neutral state, accept strict limits on the size of its armed forces and change some of its laws to respect Russian interests. Whether Mr. Putin would accept Ukrainian membership in the European Union is unclear, but doubtful, given that his opposition to a much weaker association agreement between Kyiv and Brussels led to the 2013 Maidan uprising.

“Putin wants a reordered world, with Ukraine under control and NATO rolled back,” Ms. Fix said. An American official, speaking anonymously because of the sensitivity of the topic, said that Mr. Putin wanted “not just a neutral Ukraine but a neutered one.”

Mr. Putin’s stated intentions to reorder the security architecture in Europe, undermine NATO and divide Washington from Europe go well beyond Ukraine and must not be ignored, said Norbert Röttgen, a foreign policy expert and legislator with the Christian Democratic Union, the party expected to win Germany’s election in late February. “The future of Europe is a security issue, and we must make this war a failure for Russia,” he said. “Because even if it succeeds at all the lesson is that war works.”

It is not clear how to ensure that Russia fails without a sharp and rapid increase in European support for Kyiv. European leaders talk about the need to do so and spend more to defend themselves. But they are divided over how urgent a danger Russia represents to them. They have their own financial difficulties, with low growth and aging populations, and they disagree on how much to spend on their own militaries, even as Mr. Trump is expected to demand that Europe also take over much of the burden for supporting Ukraine.

Mr. Trump’s disinterest in multilateral alliances and his desire to shift to concentration on China means that responsibility for European security “is ours now for the first time since December 1941, and Europe is not prepared for this fundamental change,” Mr. Röttgen said.

Mark Rutte, the new secretary general of NATO, who will be at Davos, argues similarly, that Europe must do more in its own defense to support Ukraine so it can negotiate from strength and deter Russia in the future, no matter who is the American president. European allies “must shift to a wartime mind-set,” he said. He will urge NATO to set a new goal for military spending at 3 percent or even 3.5 percent of gross domestic product at the next alliance summit meeting this summer in The Hague.

Given that Russia is not about to collapse, Mr. Laïdi said, “We in Europe need to deter Russia and amp up our defense and start working seriously together.”

Mr. Röttgen echoed that call. Europe simply must do more and more efficiently, and do it through NATO, with less nationalism, he argued. “Europe needs to understand that its defense industry is about security and not just about jobs,” he said.

Ukrainian leaders understand that negotiations are coming. For some time now, President Volodymyr Zelensky of Ukraine has stopped insisting that the war can end only with a full restoration of Ukrainian control over its 1991 borders, including Crimea and large chunks of eastern Ukraine, long occupied by Russian troops. Mr. Zelensky, who will visit Davos, instead is emphasizing security guarantees for his country after the fighting stops, insisting that only membership in the NATO alliance will be satisfactory.

That is unlikely to happen, most analysts and officials in Washington and Europe agree. But many, including Mr. Rutte and key members of the outgoing Biden administration, argue nonetheless that just another big push of support for Ukraine this year will bring Mr. Putin to a more serious negotiation. But it is unclear where that big push will come from.

“We still hear that Ukraine is fighting our war, but let’s tell the truth,” said Charles A. Kupchan, a former Obama administration official and senior fellow at the Council on Foreign Relations. “The United States has a policy without a strategy,” insisting that the West will support Ukraine as long as it takes and that Ukraine alone can decide when and how to negotiate, as if Washington had no interests of its own, he said. “That’s dangerous and it’s turning Ukraine into a failed state,” he said.

Some see Russia and its desire to continue the war collapsing under economic and business pressure, Mr. Kupchan said. “But I see the opposite: Russia is OK and Ukraine is running out of gas, without enough manpower or air defense, and it’s not like it’s all sitting in Western warehouses — we don’t have it.”

But even if fighting ends, the toughest issue, everyone agrees, is Ukraine’s future security. Is there a possible form of NATO membership and collective security that covers only part of sovereign Ukraine? Would membership in the European Union, also considered far down the road, be sufficient? What would Russia tolerate, and could any promises not to invade again be trusted?

Some argue — and think Mr. Trump may demand — that Europe should handle Ukraine’s security and suggest putting in European troops after a cease-fire. But would they be there to monitor a cease-fire or to police one? And if so, given the enormous size of Ukraine and its long borders with Russia, how many thousands of troops would be necessary? How much would all that cost? Would it pull troops away from defending NATO members and undermine their trust in the alliance’s commitment to collective defense? And would they not require American air cover?

The suggestion of European troops, originally floated by the Estonians and sometimes mentioned by President Emmanuel Macron of France, has been greeted with considerable skepticism, including by Poland, which has its own long border with Russia.

A senior German official, also speaking anonymously in normal diplomatic practice, calls the whole discussion premature and irresponsible, giving Russia an easy way to divide Europe and the United States. First, he said, one has to see how the war ends.

For Mr. Röttgen, the war is less about territory than about Ukraine’s sovereignty. “Ukraine must emerge as a sovereign, viable country,” he said. That at least feels doable, but what remains unclear is how to ensure that the Ukraine that emerges will not be invaded again.

Dozens of Uyghur men who fled persecution in their native China only to find themselves detained in Thailand have entered the second week of a hunger strike in Bangkok. Their fast is a last-ditch effort to pressure the Thai government to halt what the detainees fear is imminent deportation to China, where they face the risk of torture and imprisonment.

The men, who have been in Thai detention centers for more than a decade, started their hunger strike on Jan. 10, two days after they were given “voluntary return” forms to sign, according to accounts from two of the detainees.

All refused to sign the forms, but they were then required to pose for photographs. These instructions set off panic among the detainees because the same series of events in 2015 preceded Thailand’s abrupt deportation of 109 other Uyghurs to China.

The Thai authorities have said that there are no plans to send them back, and denied that a hunger strike is taking place.

One of the detainees secretly communicated with a reporter and an activist, who shared his voice messages with The New York Times. The second detainee’s account was relayed by a family member. Four other people familiar with the matter also confirmed the details. The detainees have virtually no access to anyone except for monthly visits from a doctor.

Uyghurs are Turkic-speaking Muslims, many of whom live in the far western Chinese region of Xinjiang. Determined to eliminate perceived threats of ethnic separatism, the Chinese authorities placed the region under tight surveillance starting in 2014. Later, they detained as many as one million Uyghurs and others in internment camps and prisons, stepped up birth control measures for Muslim women and placed Muslim children in boarding schools.

The persecution prompted thousands of Uyghurs to flee. The detainees in Thailand were part of a wave of more than 300 who left China in 2014 using the Southeast Asian country as a transit point in a bid to get to Turkey, which is home to a sizable Uyghur community.

On Friday night, the men were still refusing food and drinking only small amounts of water, according to a voice message from one of the detainees that was sent to Arslan Hidayat, a Uyghur-rights activist based in Washington, who shared the message with The Times. The precise number of men on the hunger strike remains unclear.

Earlier Friday, the detainee had said that he had it “on good authority” that the Thais would hand the Uyghurs over to China by Monday.

In a separate message on Jan. 13, the detainee said: “We are desperately seeking help from those living in the free world. You all know what will happen to us if we are sent back to China.”

Separately, a brother of another detainee told a reporter that he texted with him on Friday. “It has been seven days since we are on a hunger strike. But they don’t care and they are not responding to us,” the detainee wrote in the text message, which was viewed by The Times. “This morning, we are requesting to meet the U.N. but they are not allowing us.”

Both detainees and the second’s brother, like others cited in this article, asked not to be identified for fear of reprisal.

The Thai immigration authorities have repeatedly refused to allow the United Nations’ refugee agency access to the men, unlike other groups such as the Rohingya Muslims from Myanmar, according to Bryony Lau, the deputy Asia director of Human Rights Watch.

The hunger strike has increased concern among rights activists about the health of the detainees. Many are already malnourished, have chronic illnesses like heart and lung disease, and little access to health care. Five Uyghurs have died in detention, including two children.

This month, a Cambodian former opposition politician was shot in Bangkok in broad daylight, making other refugees and dissidents who have fled to Thailand fearful for their safety.

On Friday, Thailand’s defense minister, Phumtham Wechayachai, said the issue of the Uyghurs had been discussed that day at a meeting of the country’s National Security Council. He said they talked about how to “strictly adhere to the laws, and do things without creating problems for our country and other countries.”

When asked by a reporter whether the Uyghurs would be deported on Monday, Mr. Phumtham, who is also Thailand’s deputy prime minister, said, “I only just heard this from you.”

Lt. Gen. Thanit Thaiwacharamas, the acting deputy commander of the immigration bureau, denied that the Uyghurs were on a hunger strike.

In a statement, China’s Foreign Ministry said it “was not aware” of reports that the Uyghurs could be sent back to China. It added that its basic stance was a firm “crackdown on any form of illegal immigration.”

The detainees’ plight has raised concerns in the United States and in the human rights community. On Wednesday, Marco Rubio, President-elect Donald J. Trump’s pick for secretary of state, said he would lobby Thailand to not send the Uyghurs back. Speaking in a Senate hearing, he added that the situation was “one more opportunity for us to remind the world” about the persecution that Uyghurs face.

Angkhana Neelapaijit, a senator in Thailand, said she had raised the issue of the hunger strike with Thailand’s National Security Council. She said she was pressing the Thai police to allow her to meet with the Uyghurs, and plans to hold a hearing in Parliament about their situation at the end of the month.

She recalled how in 2015, as head of Thailand’s National Human Rights Commission, she was blindsided by the previous deportation of Uyghurs. The United Nations refugee agency has called that move “a flagrant violation of international law.”

At that time, protesters in Turkey ransacked the Thai Consulate in Istanbul, and the police in the capital, Ankara, used pepper spray to push back Uyghurs trying to break through a barricade outside the Chinese Embassy.

Thailand’s prime minister then, Gen. Prayuth Chan-ocha, said that China had guaranteed the Uyghurs’ safety and promised they would have “access to fair justice.” But China’s state broadcaster later aired images of the detainees with hoods on their heads as they boarded a plane to China.

Omer Kanat, the executive director of the Uyghur Human Rights Project, a nongovernment group, said that his organization later learned that a few of the deportees had received long prison sentences, but that the fate of most was unknown. “They disappeared.”

Muktita Suhartono contributed reporting from Bangkok, and Vivian Wang from Beijing.

Could this be the year, as President-elect Donald J. Trump has promised, when Russia’s war against Ukraine is brought to an end?

The possibility of peace brings “tears to my eyes,” said Valeria, 30, an English teacher from eastern Ukraine.

As Mr. Trump prepares to return to the White House on Monday, he is promising peace in Ukraine, but publicly offering no strategy for how to achieve it — aside from his stated desire to meet with President Vladimir V. Putin of Russia. So Ukrainians can only guess at what the coming months will bring.

No one, Valeria said, wants peace more than Ukrainians. But having suffered so much loss, with hundreds of thousands killed and injured, Ukrainians will not accept peace at any price, she said. She asked that her family name not be used out of fear for the safety of her father, who is still living under Russian occupation.

“Europe and America must remember that any cease-fire or negotiations will only be legitimate if they respect the sacrifices made by Ukrainians and ensure a just, secure and independent future for Ukraine,” she said.

Since Mr. Trump won re-election in November, The New York Times has spoken with dozens of Ukrainians — soldiers at the front, villagers forced to flee their homes and people in cities far removed from the battlefield but subject to missile bombardments — about their hopes and fears before his inauguration.

Many people feel frustrated — embittered by what some view as an overly cautious approach by the Biden administration, and having endured months of delays in receiving American military assistance last year after it was held up in Congress. The war is still raging, with Ukraine facing a powerful opponent and deeply dependent on American military support.

The Trump administration, most agree, will bring change. But many worry that the change will not be good, particularly if military aid is withheld.

“Some say this is the end for Ukraine,” said Anna, 29, an artist who asked not to use her surname out of concern that Russians would harass her online. “But since I consider him an unstable person,” she said of Mr. Trump, “I can’t say for sure.”

“I hold out hope for justice and that Russia will face consequences for everything it has done,” she added.

On the front lines, soldiers often say they are not only defending their home but standing as a shield protecting the rest of Europe from a revanchist Russian regime.

Maj. Yaroslav Galas, 53, who serves in the 128th Transcarpathian Mountain Assault Brigade, said he thought Mr. Trump’s desire to be seen as a winner would ultimately ensure he backs Ukraine.

“Trump understands that the victory of Russia and the defeat of Ukraine is the defeat of the United States and his personal defeat as president,” he said. “This is how the world would see it.”

Andrii, 44, a military intelligence officer fighting in the Kursk region of Russia, said every Ukrainian had experienced so much horror that the end of the war could not come soon enough.

“War is terrifying, and it needs to end,” he said, asking that his surname not be used in accordance with military protocol for soldiers interviewed at the front. “Maybe Trump will do something about it.”

But if Mr. Trump withholds military support as a way to pressure Kyiv into accepting a bad deal, he said, it may not work out the way he expects.

“It will be bad,” he said. “It will turn into a guerrilla war.”

“We won’t give up,” he said. “Many good people will die.”

Andrii was a local businessman in the border city of Sumy when the Russians stormed across in February 2022. He hid his four children, he said, picked up a gun and has barely put it down since.

“We organized ourselves and started fighting them off,” he said. “We pushed them out of the city, set up checkpoints, and they didn’t get through. There was no government, just regular people organizing and doing it.”

While political infighting and social tension within Ukraine have grown since the beginning of the war, he believes people would rally together again in the event of a catastrophic collapse of the front.

In a cemetery on the outskirts of Sumy this month, row upon row of blue and gold Ukrainian flags fluttered in a cold wind.

Kateryna Zakharuk, 25, sat by the grave of her husband, Ivan.

When their village was occupied by Russian forces in the opening days of the war, he banded together with friends to fight behind enemy lines, burning Russian ammunition depots and even capturing a prisoner, she said.

The Russians were driven back across the border, and Ivan joined the army. He was killed on Feb. 17, 2024.

Ms. Zakharuk visits his grave every week, she said.

“My friend’s brother, who was also Ivan’s friend, is buried there,” she said, pointing to the headstone. “My relative is buried over there. A boy from my village is buried right there. There are so many familiar people here.”

She has seen how Russian forces have laid waste to entire cities, leaving nothing but ashes, and worries that Sumy could suffer the same fate without American support.

“Not only are human lives ruined,” she said, “but all memories are destroyed.”

Valeria, the English teacher, said her hometown had already been ravaged. Her family is from Kreminna, in eastern Ukraine, which has been occupied by Russian forces since early in the war.

Her father is still there; she has not seen him in years.

“I don’t know if I ever will see him again,” she said. “As cynical as it may sound, even though he is alive, part of me has already said goodbye to him.”

She said she did not know what Mr. Trump would do, but hoped Ukraine would “have the primary voice in such serious decisions as our future, especially on matters of war and peace.”

“Unfortunately,” she said, “there’s a growing sense that the fate of Ukrainian citizens is often being discussed without our participation.”

Liubov Sholudko and Anna Lukinova contributed reporting.

As a truce took hold on Sunday in Gaza, potentially ending the longest and deadliest war in a century of Israeli-Palestinian conflict, two men used the same metaphor to describe how they felt.

“The weight on my chest has lifted,” said Ziad Obeid, a Gazan civil servant displaced several times during the war. “We have survived.”

“The rock lying on my heart has been removed,” said Dov Weissglas, a former Israeli politician. “We want to see the hostages home, period.”

But — both men also had a “but” — Mr. Obeid has not seen his damaged house in northern Gaza for more than a year. How bad, he wondered, is the damage? And who will rebuild a decimated Gaza?

Mr. Weissglas worried about the condition of the hostages set to be freed gradually over the next few weeks from dank quarters in the territory. And he grimaced about exchanging them for hundreds of Palestinian detainees, many of whom are serving life sentences for attacks on Israelis. “There is relief,” he said, “wrapped in caution, fears and concern.”

Privacy can be hard to come by in India. Life is a communal swirl of relatives, neighbors and friends. Cities are crowded, and prying eyes are everywhere.

Enter Oyo, a popular hotel-booking platform. The company, backed by big names in venture capital, built a hip reputation as a gateway to “love hotels” for unmarried couples. Inside its budget rooms, young lovers who might otherwise be left to steal furtive kisses in the nooks and crannies of public parks or shopping malls could exert their passions behind closed doors.

Now, Oyo is stepping back from its image as a refuge for hookups. This month, it revised its policy guidelines to give some partner hotels the discretion to deny rooms to young couples unless they provide proof of marriage.

So far, the change applies only to Meerut, a midsize city northeast of New Delhi. The company said the new policy was a response to complaints by civil society groups and was formulated “in line with local social sensibilities.”

Oyo’s move spurred memes and a backlash on social media, especially among 20-somethings. To many, it drove home the tension between traditional values and modern ideals that defines life for millions of young Indians.

Premarital sex is still largely taboo in this deeply conservative country, where marriages are traditionally arranged by families. It is widely viewed as a malign import from the less-inhibited West, and as an affront to Indian culture that is either to be policed or left unacknowledged.

The stigma around sex before marriage is about “family honor,” said Chirodip Majumdar, an associate professor at Rabindra Mahavidyalaya, a college in the eastern state of West Bengal. Nonetheless, more young people are doing it anyway, studies show.

Attitudes about premarital sex vary along class lines, Mr. Majumdar said, with higher-income people viewing it more favorably. “They have more scope of social interactions, more knowledge about birth control mechanisms, more exposure to Western culture,” he said.

Many young Indians, too, have embraced liberal attitudes toward dating and sex that transcend caste, class and religion, which still often dictate arranged marriages.

Dating apps like Tinder are popular, as are hookups. A 2022 study published in the journal Sexuality & Culture found that 55 percent of young adults in four cities in India “engaged in hooking up, indicating that the norm regarding sexual behavior might be shifting.”

Neha, a 34-year-old counselor based in Bengaluru, said she and her husband rented Oyo rooms twice a week when they were dating. Neha, who asked that her last name not be used, recalled the judgmental glances that hotel owners, including those that did not use the Oyo platform, often directed her way.

At some hotels, the proprietors questioned their marital status before turning them away.

But Oyo became such a core part of their romance that when the couple got married in 2017, their animated video wedding invitation contained a reference to the hotel platform.

“Everyone knew we were using Oyo,” Neha said, adding, “So we put that in our wedding invite.”

The lack of private spaces in India to engage in intimacy created a market for companies like Oyo.

It is not uncommon to see young lovers exchange stealthy kisses in nearly empty movie theaters or under the archways of abandoned monuments in the blazing heat of a Delhi summer. Bathroom stalls and fitting rooms are all fair game. Cybercafes can be a make-out zone.

In the acclaimed 2024 movie “All We Imagine as Light,” which explores the intersecting lives of three women in Mumbai, one of the characters finds a deserted patch of forest to have sex with her boyfriend.

Manforce, which bills itself as India’s best-selling condom brand, last year featured a series of humorous ads with couples getting it on in private corners of public spaces — a car, a park, a cinema.

Oyo was founded in 2013 and is backed by investment firms, including SoftBank. It expanded to the United States in 2019, and last year it bought the Motel 6 chain.

In India, it offers rooms for as little as 500 rupees, or less than $6, a night, no questions asked. The platform became popular with small-hotel owners, who by signing up with Oyo are required to abide by its standards and use its branding.

On Google, one of the first search questions for Oyo is “Can I stay in Oyo with my girlfriend?” Although Oyo also serves solo business travelers and other customers, the company leaned into its image, offering room searches under filters like “relationship mode.”

Now, however, it is pursuing more families.

In an ad released last year, a young couple sits at the dinner table with the woman’s family. Their marital status is unclear. After she tells her father that they have booked a weekend trip with Oyo, he looks at them, horrified.

When the couple says it is more fun with family, the father expresses confusion: “What are you talking about?” The next frame shows the entire family checking into a sparkling Oyo hotel. The father then says, “This is what you’re talking about!”

Pragati K.B. contributed reporting.