When Donald J. Trump was last president of the United States, the wealthy monarchies of the Persian Gulf had a mostly harmonious relationship with his administration. As Mr. Trump prepares to return to the White House, the leaders of those Gulf countries have generally welcomed him back.

But this time around, the Gulf states and Mr. Trump appear to be diverging on several cornerstone issues, like Israel and Iran. Differences over energy policies could also be a source of friction.

It is unlikely that there will be major tensions or ruptures with U.S. allies in the Gulf. But Mr. Trump will be encountering a region that has seen drastic shifts since Israel launched its war on Gaza in response to the Hamas-led attack of Oct. 7, 2023, in which the Israeli authorities say about 1,200 people were killed and about 250 taken hostage.

The war in Gaza, in which at least 45,000 people have been killed, according to health officials in the enclave, has rippled across the region. In Lebanon, the Iran-backed militant group Hezbollah has been battered by more than a year of fighting against Israel. And in Syria, rebels toppled the regime of Bashar al-Assad.

Now, while Mr. Trump is filling his cabinet with Iran hawks and staunch defenders of Israel, Gulf leaders have publicly been urging a softer stance on Iran and a tougher line on Israel.

They have also been calling on the United States to stay engaged with the region.

For now, the Trump administration has appeared eager to engage with the Gulf powerhouses of Saudi Arabia, Qatar and the United Arab Emirates.

In December, Mr. Trump’s pick as his envoy to the Middle East, Steve Witkoff, was in the Emirati capital, Abu Dhabi, where he attended a Bitcoin conference along with Eric Trump, the president-elect’s son. He also went to Riyadh, Saudi Arabia, where he met with Crown Prince Mohammed bin Salman, Axios reported.

Here’s a closer look at the issues facing Mr. Trump as he navigates an evolving relationship with his traditional Gulf allies.

Engagement in the Mideast

One of the clearest calls in the Gulf for Mr. Trump to avoid an isolationist agenda came from Prince Turki al-Faisal, the former head of Saudi Arabia’s intelligence services.

In an open letter to the U.S. president-elect published in November in The National, an Abu Dhabi-based newspaper, Prince Turki referred to an assassination attempt against Mr. Trump and expressed his belief that “God spared your life” in part so Mr. Trump could continue the work he had started in the Middle East during his first term. That mission was to bring “PEACE, with capital letters,” he wrote.

During his first term, Mr. Trump’s administration brokered the Abraham Accords that saw several Arab countries establishing ties with Israel.

A similar message to Prince Turki’s was delivered a few days later by Anwar Gargash, an adviser to Sheikh Mohammed bin Zayed, the U.A.E. president, at a conference in Abu Dhabi.

With the Gulf surrounded by an increasingly turbulent region, Mr. Gargash said, American leadership and partnership remained essential. “We need robust leadership that balances humanitarian concerns with strategic interests,” he said.

Going Harder on Israel

On Israel, the most striking shift in messaging in the Gulf has come from the de facto leader of Saudi Arabia, the crown prince. Speaking at an Arab League summit in Riyadh recently, Prince Mohammed for the first time called the Israeli military campaign in Gaza a “genocide.”

Just before the war in Gaza erupted in October 2023, Saudi Arabia appeared to be on the verge of forging diplomatic relations with Israel without fulfilling its longstanding precondition for doing so — the establishment of a Palestinian state. Such a deal would have reshaped the Middle East.

Under one plan, Saudi Arabia would normalize relations with Israel in exchange for stronger defense ties with the United States and American support for a civilian nuclear program in Saudi Arabia.

But recent statements by Prince Mohammed suggest that any deals are a long way off.

In addition to his statement referring to genocide in Gaza, he has also made it clear that Saudi Arabia will not establish diplomatic relations with Israel until a Palestinian state is created. That is still a distant prospect given strong opposition to such a state within the government of Prime Minister Benjamin Netanyahu of Israel.

“I think that the crown prince wanted to make his position clear and beyond any shadow of a doubt,” said Ali Shihabi, a Saudi businessman who is close to the kingdom’s ruling family.

The United Arab Emirates — a signatory to the Abraham Accords — has also signaled a hardened stance toward Israel.

The U.A.E. foreign minister, Sheikh Abdullah bin Zayed, told his Israeli counterpart last week that the Emirates would “spare no effort supporting Palestinians.”

Despite Saudi Arabia’s public stance on the status of a normalization deal, U.S. diplomats have indicated that the kingdom may be privately open to advancing one under a second Trump presidency — contingent upon a permanent cease-fire in Gaza and a tangible commitment by Israel toward a path to Palestinian statehood.

“All of that is ready to go if the opportunity presents itself with a cease-fire in Gaza as well as understandings on a pathway forward for the Palestinians,” the departing U.S. secretary of state, Antony J. Blinken, said on Wednesday. “So, there’s tremendous opportunity there.”

Détente With Iran?

During Mr. Trump’s first term, both Saudi Arabia and the United Arab Emirates championed his administration’s hawkish stance on Iran, seeing Tehran as a dangerous rival in the region.

They cheered when Mr. Trump withdrew the United States from a nuclear deal with Iran and hailed his decision to authorize the assassination of Qassim Suleimani, the general who directed Iran’s militias and proxy forces around the Middle East, in January 2020.

But the dynamics of the region have changed since Mr. Trump’s first term.

Saudi Arabia and Iran reached an accord in March 2023 that reduced tensions in the Persian Gulf and opened the door to high-level diplomatic contacts.

Bahrain, after years of tension with Iran, has made overtures to the Iranian government, with King Hamad bin Isa al-Khalifa saying there was “no reason to delay” the resumption of diplomatic relations. The tiny island kingdom also condemned Israel’s targeting of Iran last October, when a shadow war between the two countries broke out into the open with tit-for-tat attacks.

For Saudi Arabia, the goal is clear: to create a stable regional environment conducive to Prince Mohammed’s dream of diversifying the oil-dependent Saudi economy. For Iran, decades of economic and political isolation, compounded by rising domestic unrest, have made reconciliation with Riyadh a necessity.

There are also indications that Iran might be open to negotiating with Mr. Trump. Many former officials, pundits and newspaper editorials in Iran have openly called for the government to engage with Mr. Trump.

So far, Mr. Trump, too, appears open at least in charting a different course from the “maximum pressure” campaign of his first term. In November, Elon Musk, a close adviser to Mr. Trump, met with Iran’s ambassador to the United Nations, Iranian officials said.

“We have to make a deal because the consequences are impossible,” Mr. Trump said in September, referring to the threat of Iran’s pursuing nuclear weapons.

Possible Frictions Over Oil

While the Gulf Cooperation Council countries — Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates — appear open to Mr. Trump’s transactional approach to diplomacy, they could find themselves at odds with his economic policies.

A central promise of his campaign was to bolster U.S. oil and gas production, a move that could hurt Gulf economies.

If the United States increases oil production, as Mr. Trump has pledged, producers in the Gulf would have less scope to raise output without prompting a price drop.

“Increased U.S. oil exploration and production will lower prices and jeopardize the oil-driven economies of the Gulf,” Bader al-Saif, an associate fellow at the London-based research institute Chatham House, said in a recent report.

Mr. Trump is also expected to accelerate liquefied natural gas projects, reversing President Biden’s freeze on permits and increasing U.S. exports, particularly to Europe.

Qatar, one of the largest producers of the gas alongside the United States, would most likely be most affected, but it has so far played down its concerns.

Five months after Ukrainian forces swept across the border in the first ground invasion of Russia since World War II, the two armies are engaged in some of the most furious clashes of the war there, fighting over land and leverage in the conflict.

The intensity of the battles recalls some of the worst sieges of eastern Ukraine over the past three years, including in towns like Bakhmut and Avdiivka, names that now evoke memories of mass slaughter for soldiers on both sides.

The fighting, in the Kursk region of Russia, has taken on a layer of significance for the territory’s potential to play a role in any cease-fire negotiations. Facing the prospect of an unpredictable new U.S. president — who has vowed to end the war swiftly, without clarifying the terms — Ukraine hopes to use Russian territory as a bargaining chip.

Russia, relying on North Korean reinforcements, hopes to knock that territory out of Ukraine’s grasp.

“Here, the Russians need to take this territory at any cost, and are pouring all their strength into it, while we are giving everything we have to hold it,” said Sgt. Oleksandr, 46, a leader of a Ukrainian infantry platoon. “We’re holding on, destroying, destroying, destroying — so much that it’s hard to even comprehend.”

He and other soldiers, asking to be identified by only a first name or call sign in accordance with military protocol, said that attacking North Korean infantry had made the battles far more ferocious than before.

“The situation worsened significantly when the North Koreans started arriving,” said Jr. Sgt. Oleksii, 30, a platoon leader. “They are pressuring our fronts en masse, finding weak points and breaking through them.”

Russia, with the help of an estimated 12,000 North Koreans, has retaken about half of the territory it lost over the summer. Its assaults over the past week have further eaten into the territory held by Ukraine.

But Ukrainian forces have also gone on the attack in recent days, seeking to secure an area west of Sudzha, a small town in Russia about six miles from the border that has become the anchor for Ukrainian forces, which seized about 200 square miles in August.

“If they keep pressing us and we don’t push back, the enemy will feel a sense of superiority,” said Andrii, 44, a military intelligence officer. “When someone keeps hitting you, and you don’t hit back, the attacker will feel psychologically comfortable, even relaxed.”

The Russians have largely thwarted the assault, but fighting goes on and the situation remains unpredictable, soldiers said.

The intensity of the battles could be glimpsed on the road approaching the Russian border: A steady stream of tanks, armored personnel carriers and other vehicles rolled past broken down and blown-up equipment.

Russian bombs and rockets exploded with thunderous force in border villages, and Ukrainian missiles could be seen streaking across the sky in the opposite direction.

Tens of thousands of drones hunted targets, too. They have transformed the battlefield, although Ukraine has improved its electronic warfare abilities, limiting the effectiveness of drones that rely on radio signals. Russia has now flooded the theater with drones guided by ultrathin fiber-optic cables, with a flying range of more than 10 miles.

The best current defense against them is a shotgun, Ukrainian soldiers said.

The renewed fighting comes against a deeply uncertain political backdrop. The U.S. president-elect, Donald J. Trump, spent months on the campaign trail questioning American military assistance to Ukraine. He has said he wants to bring the war to a swift end, but has not indicated how.

Russian forces have been on the offensive for more than a year in eastern Ukraine, making steady advances despite staggering losses.

With its incursion, Ukraine aims to create a buffer zone to protect hundreds of thousands of civilians in the city of Sumy, less than 20 miles from the border with Russia. Ukraine also wants to ease pressure on the eastern front by drawing Russians back onto their own land.

President Volodymyr Zelensky said the campaign had sent a powerful message to the world that Ukraine can do more than play defense.

“It’s one of our wins, I think one of the biggest wins, not just last year, but throughout the war,” Mr. Zelensky said on Thursday in Germany, while meeting representatives of nations providing military support to Ukraine.

Still, some military analysts have cautioned that Ukraine’s Kursk campaign could leave its forces increasingly stretched and losing ground in its own eastern Donbas region.

Many soldiers fighting in Kursk believe that the painful losses in eastern Ukraine would have been even worse without their campaign.

“We have to understand the Russians use their most elite soldiers and best reserves in this area,” said Capt. Oleksandr Shyrshyn, 30, a battalion commander in the 47th Mechanized Brigade. “Considering what they could be doing in other parts of Ukraine, it is good.”

He was still bleary-eyed after a battle, a few days earlier, to thwart a large Russian assault.

The Russians attacked Ukrainian positions in six waves, employing more than 50 tanks, armored personnel carriers and other vehicles.

While dozens of enemy soldiers were killed and injured and a large amount of the Russian equipment destroyed, Captain Shyrshyn said, the Russians advanced a couple of miles.

“When the first wave comes, we focus on it, deal with it, and then the next one comes,” he said. There is no time to redirect artillery or other resources as the next wave moves in from a different line of attack.

“We fall behind,” he said. “Then the next wave comes, and one of them manages to reach the required section and accomplish its task.”

It remains difficult, he said, to see how so many in the West view the war in Ukraine like a video game and refuse to see the threat Russia poses to the world.

He acknowledged the decline in Ukrainian morale over nearly three years of war, but said most soldiers still understood why they must fight. “Stopping will mean our death, that’s all,” he said.

North Korea’s entry into the war, some Ukrainian soldiers said, should alarm European nations and their allies.

The North Korean troops have fought as a disciplined, dedicated and fearless force, they said, typically moving in large formations on foot, even through minefields while under heavy artillery fire and being stalked by drones. The Ukrainian authorities on Saturday said that their forces captured two North Korean soldiers and that they were the first to be taken alive so far.

Sgt. Oleksandr, the platoon leader, said the carnage in Kursk was as terrifying as anything he had witnessed since joining the army in 2014.

“You look and can’t fully grasp where you are, seeing every day how many people we destroy,” he said.

He compared it with Bakhmut, when machine gunners had to be regularly replaced because they could not handle the pace of killing. “After two hours of laying down so many people, they couldn’t take it mentally,” he said.

“It’s the same here now,” he said, sharing a cellphone video showing the aftermath of a recent assault. The field was littered with bodies, torn and twisted and piled in ways that made it hard to count the dead.

“The worst is for the infantry,” he said. “When you’re sitting there, and they’re coming at you, and everything is flying at you.”

Anastasia Kuznietsova contributed reporting.

For the last decade or more, Europe’s governments have been trying to resist covert influence operations from adversaries like Russia and China.

Now they have a very different challenge: Fending off overt efforts by Elon Musk and Donald Trump’s MAGA movement to seize territory, oust elected leaders and empower far-right causes and parties.

Even before he retakes office, Mr. Trump is making threats — perhaps serious, perhaps not — to acquire the territory of NATO allies like Canada and Denmark. And Mr. Musk, the president-elect’s biggest financial supporter, is using his social media platform X to bring the far-right Alternative for Germany party into the mainstream and smear the leaders of Britain’s center-left Labour Party.

It is not clear if Europe’s political immune system has the antibodies to defend against these new incursions.

This is not the first time a Trump ally has attempted to build a bridge with the European far right. In 2018 and 2019, the Trump adviser Stephen K. Bannon held meetings with far-right politicians across Europe. But the political landscape now is very different. The governments of Germany and France have collapsed; far-right parties are on the rise in those countries, and are already in power in several others across the continent.

A senior official from the first Trump administration, who is in line for an even more senior role in the second, was blunt in his assessment: Europe, he said, has no idea what is coming its way.

‘A very rich person expressing his opinions’

Mr. Musk spent a $250 million slice of his $400 billion fortune to help Donald Trump get re-elected. He arguably had just as much influence on U.S. politics through his own notoriety and ownership of X, the social media network formerly known as Twitter.

He aggressively campaigned against Kamala Harris (in one case sharing a fake video of her describing herself as a “diversity hire” who does not “know the first thing about running the country”) and interviewed Trump live on the platform. He is now deploying a similar playbook in Europe.

In Britain, Mr. Musk revived a decade-old “grooming gangs” scandal that unfolded while Prime Minister Keir Starmer, whose center-left Labour Party is in power, was head of public prosecutions.

Fanning the flames that were kindled by right-wing media outlets, Mr. Musk has called Mr. Starmer “utterly despicable” and says he should be “in prison.” Last week he asked his 212 million followers to vote on whether “America should liberate the people of Britain from their tyrannical government.”

According to British media reports, Mr. Musk is also considering a $100 million donation to Britain’s far-right Reform Party, which would be the country’s largest political donation ever. The party’s leader, Nigel Farage, one of the chief campaigners for Brexit, has met Trump several times, most recently at Mar-a-Lago last month.

“MAGA hates Starmer,” the former Trump administration official told The Times. He spoke on the condition of anonymity to offer his candid views while he is being considered for a role in the second Trump administration.

“MAGA loves Meloni,” he added, referring to Italy’s right-wing prime minister, Giorgia Meloni, “as long as she meets her deportation targets.”

Mr. Musk’s SpaceX is also in talks with Ms. Meloni’s government to provide secure military communications through its Starlink satellite network. At a news conference last week, she described Mr. Musk as a “very rich person who is expressing his opinions.”

‘Musk is normalizing us’

In Germany, which is holding snap federal elections next month, Mr. Musk is encouraging voters to vote for the far-right AfD, offering it the legitimacy that has long been denied to a party under surveillance by Germany’s domestic intelligence service for its links to neo-Nazis.

In an opinion piece for a major German newspaper published Dec. 28, he called the AfD the last “spark of hope” for Germany. The country, he said, is “teetering on the brink of economic and cultural collapse.”

On Thursday he live-streamed a 75-minute conversation with Alice Weidel, the AfD’s candidate for chancellor, on X, giving her the same platform he gave Trump five months earlier.

Since Mr. Musk first endorsed the AfD in December, Ms. Weidel’s posts on X have routinely gone viral, in part because he reposts them, along with numerous neo-Nazi accounts that have been reinstated and amplified. Researchers watching the online scene say far-right German influencers now post on X in English to get Mr. Musk’s attention.

Germans won’t vote for the AfD just because an American billionaire asks them to. But social media is a tool that can shift public opinion, taking ideas that were once considered extreme and inserting them into the mainstream over time.

What has kept the AfD out of power despite becoming the second most popular party in the country is a national taboo against working with the far right. The memory of Hitler, who formed a coalition with centrist conservatives, has so far kept this firewall in place.

“The firewall between the AfD and the White House is officially gone and that makes the German firewall look silly,” the AfD’s co-leader, Tino Chrupalla, told me. “Musk is normalizing us.”

Overt vs. Covert

U.S. influence campaigns in other countries are not new. During the Cold War America lent its support to friendly nations and parties and intervened — sometimes aggressively — in countries seen to be ideological adversaries.

But now the MAGA movement seems to be intentionally sowing discord within U.S. allies. That’s disorienting for Europeans who grew up imbibing American lessons about democracy after World War II.

“I can’t remember a comparable case of interference in the election campaign of a friendly country in the history of the western democracies,” said Friedrich Merz, the leader and chancellor candidate of the center-right Christian Democrats. His party is leading in the polls but will need a coalition partner to form a government.

The United States remains the main guarantor of European security as the war in Ukraine has shown. It is also Europe’s biggest export market, making the prospect of tariffs a powerful threat for European economies. And Europe has no technology companies on par with those coming out of Silicon Valley, including Mr. Musk’s X platform and his Space X satellite company.

Europe’s dependency on Russian energy long hampered its response to the Kremlin’s meddling. But the dependency is much greater in the case of the United States.

Add to that the fact that the American interference is not covert, it is happening in broad daylight, which makes fighting back that much harder.

Exploiting existing grievances

Influence campaigns work best when they tap into existing grievances. As in the United States, Europe’s trust in institutions fell in the aftermath of the 2008 financial crisis and the pandemic. Voters have become more hostile toward immigration and more worried about the cost of living and the economy. There is a growing sense that centrist leaders on left and right have failed them on these issues.

Millions of people in Europe are angry with the establishment, said Matthew Goodwin, a conservative author and commentator. “It’s not being orchestrated by Trump or Musk.”

“Musk has not created the AfD,” Mr. Goodwin added. “It helps the AfD that he is getting them attention but the underlying driver of this are policy choices that were made over the past decade.”

Mr. Musk’s provocations in Europe may be designed for maximum chaos rather than electoral success. In Britain, he trashed Nigel Farage, leader of the far-right Reform Party, after Mr. Farage declined to endorse Mr. Musk’s demand that a far-right agitator be released from prison.

“Both the Kremlin and the forces around the libertarian-authoritarian camp around Musk want to sow chaos in Europe and get rid of the liberal democratic elites,” Thorsten Benner, director of the Global Public Policy Institute in Berlin, told the German outlet Die Zeit. “We have to arm ourselves against that. But the biggest danger for our democracies comes not from the outside but the inside. Those fighting election campaigns should focus on the problems that concern voters.”

Similar levels of infighting and chaos also exist within the broader MAGA movement. Back in United States, there are signs that those in Mr. Trump’s hard line anti-immigration inner circle are tiring of Mr. Musk, especially after a spat about whether the country should expand work visas for highly skilled immigrants. In an interview with the Italian newspaper Corriere della Sera on Sunday, Mr. Bannon called Mr. Musk “truly evil” and vowed to “take this guy down.”

Whatever the direct impact of American interference on Europe’s political map in coming years, Trump is determined to enforce his priorities in Europe whoever is in government.

“At the end of the day, Trump is going to be so much more aggressive with Europe in terms of advocating uncompromisingly for the U.S. position that it doesn’t actually matter who’s in charge,” the former Trump official said. “They key thing is America First. Everything else is a distraction. Trump is going to use American strength to get his way.”

For six weeks, South Korea has lurched through its worst political crisis in decades, throwing the resilience of the country’s democracy into question. On Tuesday, it takes the biggest step toward a resolution, when the Constitutional Court begins deliberating whether to remove or reinstate the country’s impeached president.

The eight justices on the court will be the final arbiters on the fate of President Yoon Suk Yeol, who was impeached and suspended from office on Dec. 14 by the National Assembly for his short-lived declaration of martial law 11 days earlier.

The stakes are high. Rival groups of citizens have rallied for weeks, some in front of the court, either calling for Mr. Yoon’s ouster or demanding his return to office. Hard-liners on both sides have warned of “civil war” if the court does not rule in their favor.

If Mr. Yoon is removed, it will be another crushing blow to the country’s conservative camp: He will be the third conservative president in a row to be ousted, imprisoned or both before or after their term ended.

But if the deeply unpopular leader is allowed to return to office, it could set a precedent for future leaders to use martial law as a political tool, said Ha Sang-eung, a professor of political science at Sogang University in Seoul.

“I wonder what other democracies around the world would think of that happening in South Korea,” Mr. Ha said.

Mr. Yoon has vowed to triumph at the Constitutional Court. But his lawyers have said he will not attend the first hearing on Tuesday, citing fears that criminal investigators might try to detain him for questioning on insurrection charges if he leaves his fortified residence in central Seoul. His absence is expected to cut the Tuesday hearing short. But the court can proceed with its deliberations from the second hearing, set for Thursday — with or without him.

“President Yoon will defend himself at court as often as is necessary,” said his lawyer, Yoon Kab-keun.

Mr. Yoon’s martial law lasted only six hours after being voted down by lawmakers in the opposition-led National Assembly. But his attempt to put South Korea under military rule for the first time in four decades has unleashed a prolonged political uncertainty in a key ally of the United States, which has expressed concern over Mr. Yoon’s move.

While Mr. Yoon faces a parallel criminal investigation on charges of insurrection, the focus for resolving his presidency now shifts to the Constitutional Court: Its decision could help dispel some of that uncertainty, or it could add to the turmoil if its decision angers the public.

As the country’s political polarization has deepened in recent years, the court has handled a growing number of cases only it can settle: officials, prosecutors and judges impeached by the National Assembly. Mr. Yoon is the third South Korean president in the past two decades to be impeached.

In 2004, President Roh Moo-hyun was impeached by the National Assembly for violating election law, but he was reinstated by the court, which ruled that his offense was not serious enough. In 2017, the court ousted Park Geun-hye, another impeached president, for corruption and abuse of power.

“When the country is drifting without a skipper or without knowing who the skipper is, the Constitutional Court sets it back on course,” said Jung Ji Ung, a lawyer and president of a bar association for Gyeonggi, the populous province that surrounds Seoul.

South Korea has a separate Supreme Court, but it created the Constitutional Court in 1987 as the ultimate interpreter of its Constitution. Located in Seoul’s quiet old town, the court has often attracted rival activists holding banners and loudspeakers when it neared historic verdicts.

In 2005, it abolished a centuries-old practice of allowing children to adopt only their father’s family name. In 2009, it voted against a ban on nighttime protest rallies, allowing citizens to gather after hours to express their grievances, as they have in recent months for and against Mr. Yoon. In 2015, the court decriminalized adultery. In 2019, it struck down a 66-year-old law that made abortion a crime punishable by up to two years in prison.

As the number of impeachment cases grows, the court has become more politically important and so have its nine justices, who each serve a term of six years. Three are chosen by the president, three by the chief justice of the Supreme Court and three by the political parties.

The current court has eight justices, and one vacancy. Two were selected by Mr. Yoon and his party; three by the former and current Supreme Court chief justices; and three by Mr. Yoon’s predecessor, Moon Jae-in, and his Democratic Party, the current opposition.

Mr. Yoon can be removed from office if six or more justices agree he should be, but he might not be able to rely on partisanship in the court to save him. In the past, the justices have not always voted based on who backed their appointments: The court ruled unanimously to remove Ms. Park, even though some of them had been appointed by her or her party.

The court’s ruling will depend on the gravity of any constitutional and legal offenses found to be committed by Mr. Yoon, said Bang Seung-Ju, a professor at Hanyang University School of Law in Seoul. It will also weigh whether a decision not to expel him would pose a greater disadvantage to the constitutional order and national interest than would his removal, such as by furthering political instability, he said.

Prosecutors to the court are appointed by the National Assembly and say that Mr. Yoon committed insurrection when he sent armed troops into the Assembly, ordering them to seize the parliament and detain his political enemies. Since he took office in 2022, Mr. Yoon has been locked in a standoff with the National Assembly, which he called “a den of criminals” when justifying his martial law decree.

Mr. Yoon also violated the Constitution by banning all political activities and placing the news media under military control, prosecutors say.

State prosecutors have already arrested a former defense minister and several military generals on charges of helping Mr. Yoon commit insurrection. Mr. Yoon ordered the generals to break down the doors at the National Assembly, “by shooting if necessary,” and “drag out” lawmakers, the prosecutors said.

Mr. Yoon Kab-keun, the president’s lawyer, called those testimonies “corrupted.”

But legal analysts including Noh Hee-bum, a former research judge at the Constitutional Court, expect the court to unseat Mr. Yoon as early as February, in order to help ease the country’s political uncertainty and because there is enough evidence against him.

“It’s a matter of time,” Mr. Noh said.

One young soldier from North Korea said he didn’t know where he was fighting when he was sent from his isolated homeland to the frontline of the war between Russia and Ukraine. When asked whether his parents knew where he was, another North Korean soldier shook his head.

The three-minute video clip that President Volodymyr Zelensky of Ukraine posted on the social media ​platform X on Sunday showed a Ukrainian official questioning two North Korean prisoners of war with the help of a Korean interpreter. ​The Ukrainian authorities announced their capture​ on Saturday, saying they were the first North Korean troops to be taken alive. Mr. Zelensky later offered to exchange them for Ukrainian prisoners of war held in Russia.

The soldiers’ answers came in footage provided and edited by Ukraine, which controlled the production and release of the video. It offered a tiny, but rare, glimpse into the mind-set and preparedness of ​an estimated 11,000 North Korean troops deployed to help Russia’s war against Ukraine.

They appeared to back up what South Korean and U.S. officials have said in recent weeks: North Korean troops were taking heavy casualties in a foreign war waged in an unfamiliar territory while their government was keeping their deployment a secret to its people.

South Korea’s National Intelligence Service told lawmakers in Seoul on Monday that it estimates 300 North Korean soldiers have been killed and 2,700 others wounded in battles​ against Ukraine. The White House has put the toll even higher.

​Memos found with dead North Korean soldiers indicated that their government had urged the highly indoctrinated troops to end their own lives rather than be captured​ in the battlefield, according to South Korean lawmakers who briefed journalists after a closed-door meeting with the spy agency, echoing an assertion made by Mr. Zelensky. One North Korean soldier was trying to blow himself up with a grenade, shouting the name of ​North Korea’s leader, Kim Jong-un, when ​he was shot by Ukrainian troops, they said.

North Korea has not responded to reports of its troops captured or killed by Ukraine forces. ​It has never publicized the ​deployment ​or large shipments of ​North Korean artillery shells and other weapons​ sent to Russia to help its war against Ukraine​, although ​they marked the country’s first intervention in a major armed conflict overseas in decades.

In the video released by Mr. Zelensky, the voice of an official questioning the North Koreans was distorted, perhaps to prevent their identification, and the captured troops were clearly still wounded. Ukraine said the soldiers had received medical care and had been taken to Ukraine’s capital, Kyiv, for interrogation. But by posting the video clip online, Ukraine also appeared to use the POWs in its messaging to the West.

The Ukrainian leader has seized the involvement of North Korean troops for Russia as a way to try and galvanize more support from allies. South Korea, too, has cited North Korea’s growing military alliance with Russia as a source for international concern.

Experts say that comments from prisoners of war should be assessed in light of the power imbalance between captors and captives, with the knowledge that the prisoners may not be speaking freely and could be motivated by their own safety concerns or a desire for good treatment.

According to the rules governing treatment of prisoners of war under the Geneva Conventions, governments are supposed to protect a prisoner of war from being made into a “public curiosity,” a concept that is sometimes interpreted as not presenting them in any public setting.

Lying in a bed with both his hands wrapped in white bandages, one of the two North Korean POWs looked bewildered when he indicated — by nodding or shaking his head — that he didn’t know he was fighting Ukraine ​when he was captured or that he was now in Ukraine.

When he was sent to the front line on Jan. 3, he said he was only told that the North Korean troops “would train as if we were in real combat.”

“I saw my colleagues dying next to me,” he said. “I was hiding in a dugout when I got injured.”

When asked whether he wanted to return home, the soldier asked if the Ukrainians were good people. When the interpreter said yes, he said in a weak but pleading voice: “I want to live here.”

The other North Korean soldier had a bandage wrapped around his ​wounded jaw and did not speak. He nodded when he was asked whether he had parents in North Korea. But he shook his head when​ he was asked whether they knew where he was.

“​The video clip of the two soldiers shows that Kim Jong-un has not been able to find a way to justify his country’s participation in the Russia-Ukraine war to his people,” said Kang Dong-wan, an expert on North Korea at Dong-A University in South Korea. “It also showed that the North Korean troops are being wasted as cannon fodder.”

The two soldiers belonged to the Reconnaissance General Bureau, the North Korean military’s intelligence arm, the South Korean lawmakers told journalists in a briefing. The lawmakers said that when the soldiers were sent to the war, their government had promised to treat them as “heroes.”

The soldiers were captured in the Kursk region of western Russia, where North Korean forces were fighting to help Russia regain territory seized by Ukraine during a surprise cross-border incursion last summer.

​The North Korean troops were shooting at drones flying in the distance in futile attempts to destroy them, the South Korean intelligence agency told lawmakers, citing battlefield footage that it analyzed. They were also making reckless charges at their enemies without proper artillery support from the rear, it was quoted as saying.

Mr. Kim is believed to reap billions of dollars worth of oil, food and weapon technologies in return for its supply of troops and weapons to Russia, according to South Korean analysts and officials. But the troop deployment was so rushed that the ​North Korean soldiers were poorly prepared for modern warfare, especially drone attacks, they said.

On Sunday, Mr. Zelensky said that Ukraine was “ready to hand over Kim Jong-un’s soldiers to him if he can organize their exchange for our warriors who are being held captive in Russia.”

“For those North Korean soldiers who do not wish to return, there may be other options available. In particular, those who express a desire to bring peace closer by spreading the truth about this war in Korean will be given that opportunity,” he added.

Professor Kang said that by exposing the face of one North Korean soldier and his wish to remain in Ukraine, the Ukrainian authorities were endangering his safety should he be sent back to North Korea, where his statement would be seen as an act of betrayal.

​If any North Korean POWs wanted to defect to South Korea, the Seoul government was ready to negotiate with Kyiv, the South Korean lawmakers quoted the intelligence agency as saying.

The flight recorder of the Jeju Air passenger jet that crashed last month, killing ​179 people, stopped recording for​ its last four minutes, South Korean officials said on Saturday, a significant setback for investigators.

Data extracted from the so-called black box, consisting of the ​cockpit voice recorder and the flight data recorder, is generally crucial in investigations of aviation accidents. Officials in South Korea, who have been working with the United States’ National Transportation Safety Board​, have said that the ​flight data for the plane’s last four minutes​ would be ​especially important in this crash.​

But on Saturday, South Korea’s Ministry of Land, Infrastructure and Transport said that for reasons ​not yet determined, the black box of the Boeing 737-800 had stopped recording then.

“We plan to investigate why the data was not recorded,” the ministry said in a news release. ​It also said that other data and analysis would be used to try to understand what happened in last month’s disaster.

Jeju Air Flight 7C2216​, coming from Bangkok with 181 people on board, was preparing to land at Muan International Airport in southwestern South Korea at 8:59 a.m. on Dec. 29 when ​its pilot reported, “Mayday, mayday, mayday,” and, “Bird strike, bird strike,” according to officials. The pilot also told the air traffic control tower that he was “going around,” meaning he would abort his first landing attempt and circle in the air to prepare for a second one.

But he apparently did not have enough time to make a full circle. Instead, the plane approached the runway from the opposite direction and landed on its belly, without its landing gear deployed. Seeming unable to control its speed, it overshot the runway. Four minutes after the Mayday emergency report, the plane slammed into a concrete structure off the southern end of the runway and exploded into flames.​

A key question has been: What happened during ​those four minutes?

“The black box data is crucial in ​the investigation,” said Hwang Ho-won, the chairman of the Korea Association for Aviation Security. “If the​ investigators don’t have it, it will create a serious problem ​for them.”

The missing data adds mystery to the crash, which was the worst aviation disaster on South Korean soil and the deadliest worldwide since that of Lion Air Flight 610 in 2018, when all 189 people on board died.

Mr. Hwang said black boxes could be damaged by impact, fire or prolonged exposure to deep water. But it was hard to explain how the Jeju Air black box failed to record in its last four minutes, he said.​

He said that investigators might be able to reconstruct part of the conversation inside the cockpit based on interviews with control tower officials. Radar and other data suggested that the plane tried ​but failed to gain altitude after reporting a bird strike and hurried to land​, Mr. Hwang said.

Investigators have said they were looking into various possibilities, including that of the plane losing use of one or both of its engines in its last minutes.

Most of the 179 ​people who died were South Ko​reans returning home from a Christmas holiday in Thailand. The two survivors were both crew members found with injuries in the plane’s tail section.

The disaster prompted a national outpouring of grief, with memorials set up across ​South Korea, and came as the country was also dealing with a political crisis set off by President Yoon Suk Yeol’s short-lived imposition of martial law and his impeachment by Parliament.