Difficult as it was to achieve, the cease-fire in Lebanon was the easy part.

After helping to strike the deal this week, President Biden insisted that “peace is possible,” reflecting hopes that the cease-fire between Israel and Hezbollah in Lebanon could be a first step toward ending conflicts across the broader Middle East.

But the obstacles to peace beyond Lebanon are formidable, and any regional realignment is likely to fall to Mr. Biden’s successor, Donald J. Trump.

Both Israel and Iran, the regional power that backs Hezbollah, wanted an end to the fighting in Lebanon, each for its own reasons. All but decimated, Hezbollah had little alternative.

But that does not mean peace is close in Gaza. Israel and Hamas remain far apart on a cease-fire of their own. Key regional powers like Saudi Arabia still insist on a Palestinian state, a prospect that looks ever more distant. And, not least, looming over any diplomatic effort is the prospect of a nuclear-armed Iran.

In his address to Israelis explaining why he had agreed to the Lebanon cease-fire, Prime Minister Benjamin Netanyahu was unequivocal: “The first reason is to focus on the Iranian threat.”

Iran will be Mr. Trump’s first order of business in the region. That is not only because it is the linchpin of the threats facing Israel, but also because it continues to enrich uranium that can quickly be turned into weapons, and time is running out to reach a new deal to curb its production.

There are factors that work in Mr. Trump’s favor, however. Iran, which blessed the cease-fire between Israel and Hezbollah, is trying to show the incoming Trump administration that it is again open to a negotiated deal over its nuclear program, diplomats and analysts say.

With its allies Hezbollah and Hamas badly damaged and its own air defenses shown to be vulnerable, Iran wants to avoid a direct military confrontation with Israel and obtain economic relief from punishing sanctions over its nuclear program, they say.

So Tehran has been eager to display a renewed willingness to bargain over its rapidly expanding nuclear enrichment, which is within weeks of being weapons-grade, before Mr. Trump enters office.

The Iranians, along with everyone else in the Middle East, are trying to appeal to Mr. Trump’s “deal-making ambitions,” said Sanam Vakil, Middle East director for Chatham House. They are showcasing their compliance in Lebanon and have re-engaged with the Europeans, dangling the potential for a new nuclear deal, she said.

“But getting from here to the table and to a deal is a very difficult process, and the clock is ticking,” she said.

In his first term, Mr. Trump pulled out of the 2015 nuclear deal with Iran, insisting it wasn’t tough enough. He established a “maximum pressure” policy, reimposing severe American economic sanctions on Iran and adding more. Iran, its economy in ruinous shape, would like to avoid “maximum pressure 2.0,” said Ali Vaez, director of the Iran Project at the International Crisis Group.

Iran and the European countries that helped negotiate the 2015 deal and failed to preserve it — Britain, France and Germany — are currently trying to explore the possibility of a new deal, coupled with discussions about how to de-escalate tensions in the larger Middle East, where Iran has sought to expand its Islamic revolution.

The hope is to convince Mr. Trump to refrain from implementing a new set of harsh economic sanctions as soon as he returns to the presidency in January.

“Trump may be ready for ‘maximum pressure 2.0,’ but Iran can no longer support ‘maximum resistance 2.0,’” said Mr. Vaez. “They want to avoid another costly showdown with Trump and explore a deal,” he said, thinking that Mr. Trump can deliver the U.S. Congress to support one, as previous Democratic presidents could not.

To that end, Iran’s deputy foreign minister will meet European officials in Geneva on Friday, to build on an earlier meeting at the U.N. General Assembly in September.

Those same European countries sponsored a resolution last week censuring Iran for not being transparent with the U.N.’s nuclear watchdog, perhaps to display to Mr. Trump that they, too, are willing to be tougher on Iran.

Iran regularly insists that its nuclear program is for purely civilian purposes, but it is enriching uranium to a level that has no civilian use but that is close to military-grade. European officials have low expectations for the meeting on Friday, but see it as a way to prepare for Mr. Trump’s presidency and to influence his policy on Iran.

The Europeans do not want to be sidelined by any direct U.S.-Iran deal. Since Mr. Trump left the presidency, Iran’s open cooperation with China and especially with Russia has troubled Europeans, whose security is threatened by Russia’s aggression in Ukraine and Mr. Trump’s ambivalence about the NATO alliance.

“I have no expectation the meeting will produce concrete results, but it’s an opportunity for the Europeans and Iran to explore the outlines of a deal, what Iran is willing to put on the table,” said Kelsey Davenport, director for nonproliferation policy at the Arms Control Association. Once Mr. Trump takes office, the time for a new deal will be short, only some six months, she said.

That is because the 2015 deal that suspended international sanctions against Iran expires next October. If there is no new deal before then, the Europeans are expected to move in the United Nations to restore them, in what are known as snapback sanctions.

“Multilateral maximum pressure,” with U.N. sanctions on top of American ones, “is what Iran really wants to avoid,” Ms. Davenport said. The Iranians “have been very smart to signal early and clearly their willingness to negotiate with Trump.”

There are already tensions between those around Mr. Trump favoring maximum pressure and his own stated preference for a deal, she said. “That’s another reason for the Europeans to push Trump to move quickly.”

But in the effort for a broader Middle East peace, an Iran nuclear deal is just one, very difficult piece of an intricate puzzle, especially if Mr. Trump pushes to revive a Saudi-Israel normalization that seemed in the cards before the Gaza war.

After the deaths of tens of thousands of Palestinians, that deal seems farther away than ever, with the Saudis and the leaders of Persian Gulf states pressing for concrete progress toward a Palestinian state, and relations warming with their traditional enemy, Iran.

Unlike during Mr. Trump’s first term, Saudi Arabia and Gulf leaders have been less eager to confront Iran than to manage it, moving toward a clear-eyed rapprochement.

“The Saudis have no illusions about Iran,” which could still be disruptive in the region even without Hezbollah, said Suzanne Maloney, an Iran expert and director of the foreign policy program at the Brookings Institution. “A weaker Iran is not necessarily a less dangerous Iran,” she said.

If there is no nuclear deal and American maximum pressure is enhanced by the snapback sanctions, Iran, weakened by its confrontation with Israel, might then choose to go ahead and develop its own nuclear deterrent, analysts said.

Such a move would be in violation of Iran’s commitments under the Nuclear Nonproliferation Treaty and be a challenge for Israel and the United States, which have vowed to prevent Iran from ever getting the bomb.

Israel, too, is making its own calculations with a new sense of confidence and trying to ascertain what a President Trump might be willing to do or allow “to continue to degrade and weaken Iran,” said Hugh Lovatt of the European Council on Foreign Relations.

“It’s dealt with two of Iran’s tentacles from its point of view, and they now see Iran as vulnerable and open to attack,” he said.

Washington risks overconfidence that “Iran is back in the box” after the damage done by Israeli strikes to Hezbollah, Hamas and its own missile and nuclear facilities, said Ms. Maloney.

Even if weakened, “Iran can very much still play the spoiler,” she said.

For decades, American zoos have raised tens of millions of dollars from donors and sent the money to China for the right to host and display pandas. Under U.S. law, those funds were required to be spent protecting pandas in the wild.

But the Chinese government instead spent millions on apartment buildings, roads, computers, museums and other expenses, records show. For years, China refused even to account for millions more.

Regulators with the U.S. Fish and Wildlife Service, which oversees the payments, have for two decades raised concerns about this with American zoo administrators and Chinese officials alike. The U.S. government, on three occasions, froze payments to China over incomplete record keeping, documents show.

Zoos, too, have known that the money was not always going toward conservation. But they worried that if Fish and Wildlife cut off the money altogether, China could demand the return of its bears. Zoos count on pandas for visitors, merchandise sales and media attention.

Ultimately, the regulators allowed the money to keep flowing and agreed not to check the spending in China so thoroughly, according to records and former officials.

“There was always pushing back and forth about how the U.S. shouldn’t ask anything,” said Kenneth Stansell, a former Fish and Wildlife official who traveled to China throughout the 2000s to discuss pandas. He said his Chinese counterparts argued that “it shouldn’t be of any concern to the U.S. government.”

None of this has been revealed to the public.

Where Did The Money Go?

Zoos in the United States pay about $1 million a year to get pairs of pandas from China, an arrangement that regulators allow under a provision of the Endangered Species Act. Animal-rights groups have sued over similar payments for elephants, rhinos and tigers, saying that regulators were distorting the spirit of the law.

Pandas have so far escaped such scrutiny.

Panda rentals have been touted as a major conservation success. But a New York Times investigation found that what the program has done best is breed more pandas for zoos. And the conservation money at the heart of the program has been spent in ways that zoos do not reveal when fund-raising.

The Times used two decades of financial reports, internal correspondence, photos and archival records to track more than $86 million from American zoos to a pair of organizations run by the Chinese government. Zoos elsewhere in the world have contributed tens of millions of dollars more. In wildlife conservation, that is a huge sum, far larger than what zoos have spent in overseas donations for any other species.

Zoos approve which projects get financed and then list them in annual reports to the Fish and Wildlife Service. Those records show that funds were allocated to build apartment buildings far from nature reserves. China also bought computers and satellite television for local government offices and built at least three museums with the money, according to the records.

And American money helped transform a panda breeding center in western China into a bustling attraction that, according to an architect’s plans, may soon welcome as many visitors as Disneyland.

Those payments represent only what was documented. Zoo administrators have at times struggled to persuade their Chinese partners to disclose the spending.

“You had to take their word,” said David Towne, who until 2016 was the director of a foundation representing American zoos with pandas. “China felt it was not our business — that we got the pandas, and we shouldn’t tell them how to spend the money.”

Early agreements gave zoos the right to verify funding on the ground. But contracts signed recently by the National Zoo in Washington and by the San Diego Zoo make no mention of checking how money is spent.

American zoo administrators have acknowledged, in letters to regulators, that the numbers do not always add up.

Zoos in Europe, which also rent pandas, reached a similar conclusion. At Edinburgh Zoo, where two pandas lived until last year, an administrator said in 2021 that its money couldn’t be tracked because “the funds from all zoos are pooled,” according to meeting minutes. As a result, the Scottish zoo could not identify any “specific works, projects or outcomes” that it had funded.

This has been a problem for decades. When Fish and Wildlife officials asked Memphis Zoo in 2007 to identify which Chinese areas would benefit from $875,000 allocated for panda monitoring, the zoo had no answer. It wrote in an annual report that its Chinese partner had provided “NO ADDITIONAL INFORMATION.”

In a statement to The Times, the zoo acknowledged problems.

“Memphis Zoo was not able to control the funding that was sent to China as, once it was there, it was no longer in the hands of Memphis Zoo officials,” the statement said. “And there was not always information provided regarding the funding once in China.”

Melissa Songer, a conservation biologist at the National Zoo, which recently welcomed two new pandas, said that China had put donor money to good use. “They have done so much in terms of setting aside protection and doing all the right things — stopping logging, investing,” she said. “And part of that money is coming from zoos around the world.”

The National Zoo did not answer written questions about funding. The San Diego Zoo declined to comment. China’s national forestry bureau and its zoo association, which together oversee panda exchanges, also did not respond to questions.

China has indeed expanded its network of nature reserves, and some American money was allocated for patrol trucks, small ranger stations, equipment and other items needed to protect land, records show. Mr. Stansell, the former regulator, said that, on visits to China, he did see some conservation projects. And Mr. Towne, the former panda foundation director, said that, even in the absence of hard evidence, he saw signs of progress, including more professional staff working in the reserves.

But pandas live on only a portion of that land, and their habitat is shrinking. China has built roads and developed tourism in and around nature reserves, piercing the natural habitat and leaving pandas isolated in ever-smaller populations, Chinese and American scientists have concluded.

Their report estimated that wild pandas have less territory to roam than they did in the 1980s, before the influx of funds from foreign zoos.

“It’s in everybody’s interest to portray these conservation efforts as great successes,” said Kimberly Terrell, who traveled to China while working as director of conservation at Memphis Zoo.

“There was never any real evaluation of the programs,” she added. “In some cases, it was really hard to see the connection between those programs and giant panda conservation.”

(Dr. Terrell, now a scientist at Tulane University in Louisiana, settled an unrelated gender discrimination lawsuit against the zoo in 2018.)

The Fish and Wildlife Service said it takes federal law “very seriously” and requires “sufficiently detailed financial accounting data” from zoos with pandas.

Dan Ashe, the agency’s former director, called the funding disagreement between China and the United States “a technical matter.” Mr. Ashe said that he had approved new reporting standards to maintain a program that he felt significantly benefited conservation. “We had to come up with a solution,” he said.

Mr. Ashe now heads the industry association for American zoos.

A Secret Compromise

In 2010, Mr. Ashe led a delegation of senior American wildlife officials to China for a high-stakes meeting.

The panda-rental program was on the verge of falling apart, records show. If he could not reach an agreement with his Chinese counterparts, pandas in Atlanta, Memphis, San Diego, and Washington might have to return to China.

The program’s finances had been rocky from the start.

Early money had gone to what Zoo Atlanta called a “drastic expansion and construction” of a panda breeding center in Chengdu, western China. Millions more went toward infrastructure in and around nature reserves, including roads, buildings, and water hookups — money that regulators questioned. One National Zoo project, a mixed-use building with apartments and office space, was 30 miles from a nature reserve.

“While we understand the need for establishment of an infrastructure in China, we feel strongly that construction of facilities alone will not accomplish the goal of enhancing the survival of pandas in the wild,” regulators at the Fish and Wildlife Service wrote to the National Zoo.

The zoo industry pushed back. “Conservation activities in the wild cannot occur if the infrastructure does not exist,” the industry group currently headed by Mr. Ashe, now called the Association of Zoos and Aquariums, responded.

The Fish and Wildlife Service ultimately approved most of the funds.

Then, in 2003, regulators froze money to China because of a lack of documentation, records show. But they soon gave in to Chinese demands for less detailed reporting.

“The service thought that was a reasonable way to move forward to keep the program going,” Mr. Stansell, the former agency official, said.

Back and forth it went for years, with the Chinese groups sometimes withholding information or spending money on projects with only loose connections to conservation, and American regulators periodically freezing funds.

Zoo Atlanta submitted a funding proposal for a 27,000-square-foot building, 48 sets of office furniture and 50 miles of road, along with computers and a copy machine, for “nature reserve infrastructure projects” in the northwestern Chinese province of Gansu, records show. Zoo Atlanta declined to comment, saying it did not have information on old projects.

So, when Fish and Wildlife officials landed in Beijing in 2010, years of money issues were coming to a head. The Chinese groups had stopped reporting their spending altogether, and the American regulators had frozen $12 million in payments over two years, according to internal National Zoo documents.

The zoo’s employees acknowledged that they couldn’t verify spending and fretted about losing their pandas. “The goal is to find a compromise,” they wrote.

“This is a good opportunity to ‘update’ the process,” another document read.

The zoos disclosed none of this publicly. “All of that money goes back into conservation research in China,” Don Moore, a National Zoo administrator, told ABC News that year, even as the zoo’s payments were frozen.

Ultimately, the zoos got the compromise they wanted. Fish and Wildlife regulators agreed to reduce oversight. Going forward, zoos could approve Chinese funding proposals directly, rather than sending them to the agency for review, Mr. Ashe said in an interview.

“What it did was put the accountability in the right place,” he said. The zoos are “accountable to demonstrate that they are reporting significant and meritorious conservation projects, not the Chinese.”

Panda Disneyland

Even with more lax reporting requirements, problems persisted.

Three of the zoos paid for office equipment for local government forestry bureaus.

Other money went to captive pandas, rather than to pandas in the wild. Memphis Zoo earmarked hundreds of thousands of dollars for animal enclosures, bamboo and veterinary facilities at Shanghai Zoo.

In 2017, a Chinese government group failed to show how the San Diego Zoo’s money had been spent, records show. In a letter to regulators, the zoo blamed a change in leadership at China’s national forestry bureau.

Animal-rights groups and scholars say that the heart of the problem is lax enforcement of the Endangered Species Act.

“It’s really alarming that they’re approving these things in the first place,” said Delcianna Winders, an animal-law professor at Vermont Law and Graduate School. “And then there’s no follow-up to track that the money is actually going to what it’s supposed to be going to.”

The Fish and Wildlife Service said that the donations were “an important tool to support conservation of endangered and threatened species.”

American zoos continue to advertise that they are saving a species in the wild. But in western China, where the wild panda ecosystem is more fragmented than ever, panda tourism is booming.

The Chengdu breeding center, which American zoos helped renovate two decades ago, now has 11 million visitors a year and its own IMAX theater. It is a zoo in its own right, one that controls a third of the world’s pandas. The campus is so large that tourists take shuttle buses from one end to the next.

On a visit in August, visitors thronged through the gate at 7 a.m. to catch a glimpse of the pandas before they retreated to air-conditioned enclosures.

The center is planning a satellite facility, its second. When complete, the complex expects to host 20 million annual visitors, more than Disneyland, according to an architecture firm’s plan.

The development is part of a larger Chengdu tourism push that includes new resorts and an international panda festival. The Chinese state news agency Xinhua said the goal was to “fully tap the brand value, cultural value and economic value of the giant panda.”

Joy Dong and Eve Sampson contributed reporting. James Lambert, Dylan Freedman, Kirsten Noyes and Muyi Xiao contributed research.

It sent a shock through Paris, a city striving to transform itself into one of the great cycling metropolises in the world: a bicycle rider, crushed under the wheels of an SUV in a bike lane just a few yards from La Madeleine, the landmark neoclassical church, in what prosecutors suspect was a deliberate act of road rage.

A murder investigation has been opened, and last week, Mayor Anne Hidalgo led the Paris City Council in a minute of silence for the cyclist, Paul Varry, a 27-year-old who was also a cycling advocate. Ms. Hidalgo, a member of the Socialist Party, delivered an emotional speech in which she signaled she would continue to roll out her famously aggressive policies that aim to drastically reduce the role of the automobile in Parisian life.

“I am truly angry,” she said. “The future does not belong to cars.”

An outpouring of emotion over Mr. Varry’s Oct. 15 death has put a spotlight on the dangers facing cyclists in a city that has seen an explosion in bikes and cycling lanes in recent years. But it has also underscored the frustrations that motorists increasingly feel in a place that has chosen to limit the movement, speed and parking options of cars.

In recent weeks, as cycling organizations, spurred by the death of Mr. Varry, have demanded more protections from aggressive drivers, others have complained about Parisian bikers themselves, some of whom have earned a reputation as dangerous risk-takers.

Ratcheting up tensions this month is a new policy banning motorists from driving through the four arrondissements, or districts, in the heart of the city, rekindling the argument that Ms. Hidalgo’s anti-car stance is impractical, bad for business, and caters mostly to wealthy liberals who can afford to live in the city center.

“She is putting a garrote around Paris,” Patrick Aboukrat, a boutique owner in the fashionable Marais neighborhood, said this week, placing his hands on his neck for effect.

The debate in the French capital reflects the challenges facing policymakers around the world as they ask constituents to alter ingrained life habits in the fight against climate change. Ms. Hidalgo’s experiment — which has turned many Parisian streets into whooshing parades of pedaling commuters — is also unfolding in a city that has long harbored an innate tension between the big-city need for speed and the more languorous pleasures of “la belle vie.”

If the rest of France thinks of the stereotypical Parisian as eternally in a hurry, and perhaps a little rude along the way, it is also the place that gave rise to the 19th Century concept of the flâneur, the strolling, poetically minded observer of city life, who required time to adequately savor it. The German cultural critic Walter Benjamin even asserted, in what may be an urban myth, that some flâneurs slowed their roll by walking with a turtle on a leash.

Ms. Hidalgo, in her fiery speech last week, effectively embraced the turtle. Going “very quickly from point A to point B,” she said, “is not living in a civilized way in a city. In a city, one stops, one takes one’s time. We respect others.”

But for some Parisians, especially pedestrians, it is cyclists streaking wantonly through intersections who have become the threat. A recent article in Le Monde described the rising trend of “bicycle bashing,” noting social media complaints about bikers bearing the hashtag #cyclopathe.

Ms. Hidalgo, who took office in 2014, announced this week that she would not seek a third term. She has made reducing car traffic a signature effort.

Her government has already turned roads on the banks of the Seine into walking and bike paths, created hundreds of miles of new bike lanes elsewhere, and reserved most of the Rue de Rivoli, a key east-west thoroughfare, for cyclists.

The city has reduced the speed limit on Paris’s ring road and plans to remove 60,000 parking spaces by 2030. It is currently enacting a soft rollout of the new traffic restrictions in the First, Second, Third and Fourth arrondissements, on the right bank of the Seine, an area that encompasses the Louvre museum, the Tuileries gardens and neighborhoods like the Marais. Buses and taxis are exempt from the prohibition, but regular drivers must have a specific destination inside of the zone in mind.

In an interview last week, Mr. Aboukrat, the head of a merchants’ association called Comité Marais Paris, said his group is planning to take legal action to stop the ban, which he predicts will harm his business.

“People will look on Waze and see that it is a forbidden zone, and they won’t come,” he said, referring to the navigation app.

Yves Carra, a spokesman for the group Mobilité Club France, until recently known as L’Automobile Club Association, said he is frustrated that the Paris government, which represents about 2 million people within the boundaries of the city, is making decisions that affect the 12 million-plus people who live in the metropolitan area.

The car, he said, was a valid technological response to Paris’s suburban sprawl; Ms. Hidalgo’s policies, he said, was detrimental to “the people who need these cars to be able to move around and live.”

Mr. Aboukrat agreed. “It’s stunning for a Socialist mayor to stop the banlieues from coming in, or to cut off their liberty to circulate,” he said, referring to working-class suburbs.

Ms. Hidalgo, among other things, has argued that her policies have contributed to significant reductions in the amount of air pollution in the city.

Parisians’ love for bicycles has a long history, including what has been described as a sort of “fever” for its precursor, the velocipede, in the 19th century. During World War II, the bicycle became the principal means of transport on Parisian streets, according to Clément Dusong, a scholar of urbanism, but it fell out of favor after the war and the city began adapting to the automobile.

Mr. Varry, the cyclist who was killed, hailed from a close-in suburb, Saint-Ouen-sur-Seine, where he had made the cause of cyclists “the commitment of his life,” according to the City Council there.

According to the authorities, Mr. Varry was riding a bicycle in a cycling lane near La Madeleine on a Tuesday evening. The driver of the SUV, a 52-year-old man, began illegally driving in the lane as well, and at some point, ran over Mr. Varry’s foot. Mr. Varry banged his fist on the hood. Shortly thereafter, prosecutors say, the driver, whose teenage daughter was in the SUV with him, ran Mr. Varry over.

The motorist, whose name was not disclosed by prosecutors, has been detained. A lawyer for the man described him as a father of four who worked as a sales representative. He said that his client was trying to turn right, and did not run Mr. Varry over deliberately.

The incident sparked more than 200 protests across France, including one on Oct. 19 that gathered roughly 1,000 people in Paris. It has also spurred cyclists to talk about road rage they have experienced from drivers; some have even likened it to the #MeToo movement.

“What Paul’s death showed is that there are a lot of cyclists who experience dangerous things on a daily basis, but it has received very little media coverage,” said Antoine Breton-Godo, a cyclist in his 20s. “So it was a trigger.”

A recent poll in Le Parisien newspaper suggested that the effort to limit cars is supported by roughly half of residents, with 27 percent saying the Hidalgo government is doing a good job, and 23 percent saying that more should be done. Ms. Hidalgo is supporting a protégé and fellow Socialist, Rémi Féraud, in the 2026 mayoral election. Mr. Féraud said he plans to continue with Ms. Hidalgo’s transportation policies.

In direct response to Mr. Varry’s death, France’s transportation minister, François Durovray, created a new “mission against violence to protect all users of the road.” This month, a pro-cycling group that Mr. Varry belonged to, Paris en Selle, or Paris in the Saddle, announced it had drawn up a list of 200 intersections and 25 major roads that they say are in urgent need of changes to make them safer.

Ms. Hidalgo said that she hoped that someplace in Paris would be named in Mr. Varry’s honor, adding him to the list of martyrs and heroes whose names already adorn the city streets.

Late at night, half a dozen Ukrainian infantrymen leaned over a map spread on wooden pallets inside a building. Within an hour they would embark on one of the most dangerous deployments of the war, a nighttime operation across the Dnipro River.

Vyshyty, a company commander, was issuing orders for an operation last May. The unit would be providing support for assault troops, he told them. “If they retreat, you hold positions, give them covering fire, and evacuate the heavily wounded,” he said.

The men of 126th Territorial Defense Brigade are among elite forces of the Ukrainian army. Trained by British special operations forces, among others, they have been conducting cross-river operations, alongside marine infantry brigades and special intelligence units, against Russian forces in the southern Kherson region for the best part of two years.

Over several weeks this spring, commanders and soldiers of the brigade allowed a team of reporters to accompany them on operations. They also described some of their earlier operations that had not been previously reported. Because of security restrictions, some details and locations have been withheld and soldiers are identified only by first names or call signs.

For months the Dnipro River has been a brutal battlefront, as Ukraine attempted a show of force with an amphibious assault against Russia’s western flank. The Ukrainians took untold casualties as they clung to tenuous positions in the village of Krynky on the eastern bank.

The 126th Brigade has been in the forefront of the river operations, conducting reconnaissance and assaults.Their exploits illustrate the desperate cost of the war as Ukraine has tried to make gains against a vastly superior force.

Formed by volunteers in the city of Odesa in the days after Russia’s full-scale invasion of Ukraine in 2022, the 126th Brigade had few members with military experience. But its volunteers included entrepreneurs, self-declared hippies and geeks who made qualities like training and good leadership a priority.

“It was a bit of a miracle,” said Rul, 38, the brigade’s chief sergeant major. “We did not know each other but our minds all went in one direction.”

With training from British, American and Swedish instructors, the brigade adopted elements from NATO drills, which differed from Ukrainian and Soviet models in their attention to detailed preparation and a focus on keeping soldiers alive.

“Good management saves lives,” said Rul. “And if you want to win, you have to save more lives than the Russians do.”

The 126th fought at the city of Mykolaiv, and in the counteroffensive in 2022 that recaptured Kherson. The hardest test of all, soldiers and commanders said, has been the assaults across the Dnipro.

Ordered to punch through Russian positions beyond the village of Kozachi Laheri on the eastern bank in August 2023, Krab, one of the brigade’s commanders, led a platoon across the river and advanced 800 meters from the riverbank. But fighting was so intense, the soldiers ran out of ammunition and discovered the real difficulty of a cross-river assault: bringing supplies across half a mile of water.

Forced to pull back, they were soon fighting with their backs to the river.

Two months later, in October, the 126th joined units from several marine brigades in a large-scale amphibious assault on the village of Krynky on the eastern bank. That operation has become notorious among Ukrainian forces as a “suicide mission,” in which wave after wave of men were ordered across the river to attack Russian positions with little gain.

Russian firepower was so heavy, soldiers and marines said in interviews at the time, that men were cut down midstream or before they set out, as they were loading into boats. When they reached the eastern bank, they had to clamber over corpses to disembark into a moonscape with no shelter but bomb craters and splintered trees.

The 126th Brigade units took their share of casualties — one company lost half its men over months of fighting — yet it was the brigade’s reconnaissance and assault units that first forged a route into Krynky and established positions there. In recognition of its capabilities, the 126th has been selected to become a new marine brigade.

Those assault troops all came back alive from Krynky after seven days of fighting, said Mudri, 31, their commander, who met them as they returned.

But the Russian shellfire intensified after the first week, soldiers in infantry units that followed up on the initial assault said. Serhii, a 41-year-old father of three, said his unit fought for six hours to advance just 80 yards. The unit was so pinned down that they could not evacuate the wounded for four days, he said.

“The medic bled out and died,” Serhii said. “He was lightly wounded but he died.”

Others described nearly drowning in the river, weighed down by their weapons and kit when their boats were sunk.

Rybak, 41, who ran a small angling company before the war, was thrown in the water when his boat hit a mine. Unable to move his legs — he later discovered his back was broken — he managed to paddle to the riverbank.

He said he hid among the corpses of fallen comrades for six hours, slipping in and out of consciousness, clinging to the bank by digging two commando knives into the grass. He was later rescued by a passing boat but only by chance.

Through October fighting was at close quarters, house to house, with Russian soldiers in one building and Ukrainians in the next, Serhii said. The men sheltered in basements. Neither side could go out to recover the dead.

Animals were eating the corpses, Serhii recalled.

By November the Russian troops had pulled back and were flattening the houses with aerial guided bombs. Ukrainian troops were scattered and without communications.

Ihor, a commander in the assault battalion, took a unit into Krynky for nine days and scoured the bombed-out buildings to register which units and men were still alive and fighting.

“Thanks to that we worked out who was where,” he said. “We named it Chaos Street.”

The brigade began supplying its men with ammunition, food and water by drone since the route across the water was so dangerous. They held positions in Krynky through the winter but the Russian bombardment steadily demolished all cover.

By early this past summer the brigade was starting operations at a different part of the river.

“The good thing is there is good soil so you can dig in,” Vyshyty, the company commander, told the squad readying for the operation last May. Russian positions were close, he said, so he advised the men to whisper to avoid detection.

In a village a safe distance from the river, the men geared up, swinging on body armor and packs, jumping to shift the weight. They cracked jokes and smoked cigarettes as the tension grew. One soldier asked the commander to let them know the result of a boxing match while they were on positions.

Then suddenly they fell silent, piled into vehicles and slid away into the night.

The route in was the most dangerous part of the operation, Vyshyty, 27, said after the men departed. They would face Russian artillery fire, guided bombs and the most lethal of all, attack drones, as they drove to the riverbank and loaded onto boats.

Both sides had jamming devices to guard against drones but the protection was imperfect, Vyshyty said. “Something will go wrong,” he said with a shrug, “or nothing will go wrong.”

He stayed up till dawn monitoring the operation and allowed Times reporters to join him. Two engineers arrived back from the riverbank. They paced around the room, high from adrenaline after a dash to evade drones as Vyshyty debriefed them.

In the early hours bad news came through from Krynky. The brigade’s last unit, trapped in the village for weeks, had finally received orders to pull out. They made it to the pick up point but just before dawn their boat was hit by a Russian drone. One of the brigade’s most experienced soldiers was killed.

“He was the best warrior,” Vyshyty said a few days later.

Yurii Shyvala contributed reporting from Kherson, Ukraine.

Prime Minister Justin Trudeau of Canada on Friday night landed in Florida to see President-elect Donald J. Trump at Mar-a-Lago, two officials with direct knowledge of the visit said, after a threat by Mr. Trump to impose across-the-board tariffs on goods from Canada and Mexico on Day 1.

The visit makes Mr. Trudeau the first head of government from the Group of 7, a key forum of global coordination consisting of the world’s wealthiest democracies, to visit the president-elect.

Mr. Trudeau and Mr. Trump were to dine together on Friday evening, one official said, along with a delegation of senior Trump allies poised for top trade and security positions in his new administration.

Mr. Trudeau was accompanied on his visit by Dominic LeBlanc, Canada’s minister of public safety. The Canadian prime minister was expected to stay in the area overnight, but not at Mar-a-Lago, Mr. Trump’s private club and home in Palm Beach, Fla.

The Trump transition team did not respond to requests for comment, and there was no information released about Mr. Trump’s schedule on Friday.

Mr. Trudeau has been scrambling to formulate a plan to respond to the threat made this week by Mr. Trump to impose a 25 percent tariff unless Mexico and Canada take action to curb the arrival of undocumented migrants and drugs across their borders into the United States.

Mr. Trump said he would sign such a measure on his first day in office, a move that could potentially cripple trade across the continent.

The threat was also seen as an opening salvo in what would most likely be a long renegotiation of the trade agreement among the three North American nations known as the USMCA —United States, Mexico, Canada trade agreement, the successor to the North American Free Trade Agreement.

Mr. Trudeau has tried to project calm and confidence, saying that he believed that Mr. Trump would see that tariffs would harm both countries, which are each other’s biggest trading partners. About 80 percent of Canada’s oil and 40 percent of its gas are exported to the United States, and the two countries are deeply intertwined through the joint manufacturing of cars, as well as in multiple other industries.

The Mar-a-Lago visit on Friday, which was initially reported by The Globe and Mail newspaper on the basis of tracking Mr. Trudeau’s plane, is intended as a direct effort by Mr. Trudeau to show that he has a plan to address Mr. Trump’s border concerns, and that tariffs should be avoided for the sake of both nations’ economies.

Mr. LeBlanc, the Canadian public safety minister, was given the task of drafting tougher border measures. He said this week that he was preparing to deploy additional staff, as well as drones and helicopters if needed, to better manage the border between the two countries.

The security and trade issues at the heart of the Friday meeting were also reflected on the Trump side of the table: The dinner, an official said, was attended by Gov. Doug Burgum of North Dakota, whom Mr. Trump picked to be interior secretary; Howard Lutnick, who is Mr. Trump’s selection for commerce secretary; and Mike Waltz, Mr. Trump’s choice for national security adviser.

Mr. Trudeau’s response to Mr. Trump’s tariff threats contrasts sharply with that of Mexico’s president, Claudia Sheinbaum. Mr. Trudeau and other senior Canadian officials have sought to distinguish Canada’s position from Mexico’s, highlighting that Canada is better aligned with the United States and Mr. Trump’s agenda on three key issues: the borders, restrictions on China and bringing well-paying jobs back home.

Ms. Sheinbaum has been firmer, threatening retaliatory tariffs if Mr. Trump made good on his threat.

The split has driven a wedge between two allies, Canada and Mexico, who were able to leverage their relationship to negotiate a favorable agreement during Mr. Trump’s first presidency. The trade pact is officially up for renegotiation in 2026, but analysts say they believe that Mr. Trump’s decision to put tariffs against the two U.S. neighbors on the table even before he takes office indicates that a renegotiation of that agreement could come sooner than planned.

Mr. Trudeau is facing considerable pressure over how to handle this difficult moment. The imposition of tariffs on Canada would throw the country into recession, economists believe, as doing business with the United States is the lifeblood of the economies of several Canadian provinces.

But Mr. Trudeau is in a precarious political moment, too, after nine years in power. He faces elections in the coming months, and polls show his party, the Liberal Party, is set to lose badly to the Conservatives led by Pierre Poilievre.

And as Mr. Trudeau has been trying to define a negotiating position to counter Mr. Trump’s unilateral tariff threat, the leaders of some provinces have charged ahead with their own proposals. Most prominently, Doug Ford, the premier of Ontario, has said that Canada should ditch Mexico and directly negotiate a new deal with Mr. Trump.

“To compare us to Mexico is the most insulting thing I’ve ever heard from our friends and closest allies, the United States of America,” Mr. Ford said earlier this week, adding that Mr. Trump’s descriptions of Canada were “like a family member stabbing you right in the heart.”

Mark Walker contributed reporting from West Palm Beach, Fla.

On the lamp posts in northeast Dublin, campaign posters are stacked one on top of the next, the faces of prominent politicians and newcomers competing for attention ahead of Ireland’s general election on Friday.

But Janice O’Keeffe, 44, who was collecting a cup of coffee on Thursday morning from a cafe on Sean McDermott Street, said she was still undecided. One thing was certain: She was fed up with the establishment.

“They’ve had 100 years to prove themselves and they haven’t done much,” she said of Ireland’s two main political parties, Fianna Fáil and Fine Gael.

The two parties, both of which are broadly center-right, have run the Republic of Ireland for alternating periods since the founding of the modern Irish state in the early 20th century. At the last general election, in 2020, neither won a big enough majority to govern alone. So, along with the Green Party, they formed a coalition that kept out their main opposition: Sinn Féin, which had won the popular vote for the first time.

As Ireland heads to the polls, many voters have voiced disillusionment with the government, citing issues like the steep cost of living, health care and immigration.

Despite that, the duopoly of Fianna Fáil and Fine Gael is expected to hold, partly because neither is willing to enter a coalition with Sinn Féin, a left-wing nationalist party that for decades was ostracized because of its history as the political branch of the Irish Republican Army.

In the last election poll from The Irish Times, Fianna Fáil, Fine Gael and Sinn Féin were neck-and-neck, with 21 percent, 20 percent and 19 percent, respectively.

Here in northeast inner-city Dublin, locals say the issues facing voters feel particularly acute. There is vast wealth inequality in the district, with pockets of affluence existing alongside deprivation. A boom in commercial development and an influx of well-paid tech workers from multinational firms lured by Ireland’s corporate tax breaks has added to the feeling among some longstanding communities of being left behind.

Then, just over a year ago, the city was left reeling after a knife attack set off a night of rioting and looting. The outburst of violence, which was stoked by anti-immigrant rhetoric and far-right disinformation, shone a spotlight on deeper societal issues that remain largely unresolved.

Surging demand for housing has overwhelmed limited rental stock, exacerbated by a failure by successive governments to invest in public housing. And as the number of new immigrants reached its highest level this year since 2007, a fault line has grown in Irish society and toxic narratives have gained a toehold, experts say.

“There is this real polarization at the moment, and our focus has to be: How do we help these kids growing up here?” said Jonathan Dowling, 38, a youth work leader at Belvedere Youth Club in the north inner-city. “I don’t tell people, ‘Don’t sell drugs,’ or ‘Don’t commit crime’ or ‘Don’t be racist,’” he said. “We create a platform for them to see that there is right, there is wrong and here’s your opportunity, and it’s down to them to make a decision.”

Dean Murray, 26, another youth worker, said there were often negative stereotypes about the area, where he also grew up, but that the community was tight-knit.

“Most people from here love it,” he said. For most of his peers, the biggest issues were the cost of groceries and lack of housing, he said, adding, “I think people just want change from that constant perpetuating cycle of government saying they are going to do things, and then not.”

The range of proposed solutions to Ireland’s issues is reflected by the broad swath of candidates vying for Dublin Central constituency’s four seats. There are the established candidates from the country’s center-right parties, along with Mary Lou McDonald, the leader of Sinn Féin; progressive left candidates; a nationalist anti-immigration candidate; and even Gerry Hutch, a man prosecutors have described in court as the head of a crime family.

On Wednesday, Gary Gannon, a center-left Social Democrat, was knocking on doors in the fading evening light in a final push for votes. He has represented this Dublin constituency since 2020. Concerns about housing have been a major theme for constituents, he said, but he felt the emphasis on immigration concerns had lessened since last year.

“What breaks down fear is connection,” he said. “The far-right agitators who have built their name on immigration, people realized once they stopped talking about immigration, they started talking about lessening reproductive rights, and attacks on LGBT people, and people realized that doesn’t resonate with them.”

He said the city needs “strong legislators,” not just someone to give voice to grievances. “But it can be a bit of a harder sell to say, ‘I’m not just going to speak to your anger, I am going to work to resolve it,’ because that becomes a long process,” he acknowledged.

A short walk away in the East Wall neighborhood, Malachy Steenson, a right-wing nationalist candidate running on an anti-immigration platform, offered a decidedly different vision as he knocked on doors. Mr. Steenson said traditional media had overlooked the importance of immigration to voters in neighborhoods like East Wall, adding, “Our obligation is to our own.”

Adrienne McGuinness, 55, and Dawn Everard, 54, were canvassing for him and said they became politically active two years ago in frustration over the state housing asylum seekers.

“We pay taxes, we all work, and then everything feels like it’s getting dumped on us,” Ms. Everard said. Ms. Guinness added, “We definitely are forgotten.”

Some right-wing nationalist and anti-immigration candidates may win seats, said Gail McElroy, a professor of politics at Trinity College Dublin. “It will be a big issue in certain local constituencies where there are plans to provide accommodation for large numbers of asylum seekers,” she said, adding, “The mainstream parties are kind of avoiding it,” focusing attention instead on the economy.

Sinn Féin is hoping that those disillusioned with the status quo may turn to them. After a surge in support in 2020, the party had been expected to perform well at this election, but its polling numbers have sagged during the second half of this year, thanks in part to internal party scandals.

On Thursday, Ms. McDonald, the party’s leader, appealed to people who might have traditionally steered away from the party to “lend” their support in order to challenge the two main parties.

“If you want a change of government, vote for Sinn Féin,” she said, standing in front of government buildings. “Lend us your vote for this election.”

Despite the disillusionment with establishment parties, the country’s unique form of proportional representation that uses ranked voting insulates it from the wild swings seen in other democracies, said Professor McElroy. As a result, she said, “The system rewards those with less extreme positions.”