NATO’s New Boss: Affable, Pragmatic and Ready for Trump, if Required

Mr. Rutte, known as a flexible pragmatist, will bring his experience at conciliation to the 32-nation military alliance when he takes over as secretary general from Jens Stoltenberg on Oct. 1.

As it celebrates its 75th anniversary with a summit in Washington this week, NATO, which was founded to deter the former Soviet Union from further expansion in Europe, has found renewed purpose in its support for Ukraine against Russia’s invasion. Beyond that challenge, NATO faces a Russian government forging stronger ties with China and Iran.

Leading member states like France and Germany are dealing with the empowerment of far-right parties with clear sympathies for Moscow. Hungary and Turkey are authoritarian democracies. And there are new demands.

Then there is the strong possibility that Donald J. Trump, a vocal skeptic about NATO and aid to Ukraine, will return to the White House as the leading presence in what remains an American-dominated alliance.

But Mr. Rutte, 57, has managed four difficult and different ruling coalitions in the Netherlands with aplomb, putting the need for agreement before personal ideology. He is a known quantity for other leaders, and has been praised both by President Biden, who pushed him to take the job, and by Mr. Trump, who once said after an Oval Office meeting, “I like this guy!”

Unlike Mr. Stoltenberg, a Norwegian, Mr. Rutte comes from a country fully integrated in both NATO and the European Union. “That is really substantively important now, because we really need both organizations to work more closely together,” said Camille Grand, a former assistant NATO secretary general now at the European Council on Foreign Relations. That synergy will be necessary to enable Europe to do more for its own defense as Washington turns toward Asia, he said.

“He is a nice and easy guy, but also extremely tough, who does not suffer fools gladly,” said Robert de Groot, a former Dutch ambassador to the European Union who has worked closely with Mr. Rutte since 2011. “He’s extremely kind and loyal, but he will drive you like he drives himself.”

Mr. Stoltenberg said he was hesitant to give Mr. Rutte any advice, “but what is obvious is that the main task for NATO is to ensure that we are united.”

Mr. Rutte, the son of a car dealer, has a penchant for finding common ground, rather than pushing his own point of view.

He is a private person of regular habits who lives alone, does not cook, drives an old Saab and goes to the same summer house every year. Those habits limit what he considers to be distracting choices that divert him from his real love — politics and his job.

He is particularly fascinated by American politics and regularly sees Robert A. Caro, the author of a seminal biography of Robert Moses, the urban planner who helped create modern New York City.

In an interview, Mr. Caro described his friendship with Mr. Rutte and a childhood friend, Koen Petersen, now a Dutch senator. In 2015, the two men sought out Mr. Caro, who reluctantly agreed to have lunch with them at Patsy’s, a traditional Italian restaurant in Midtown Manhattan, to quiz him about Mr. Moses.

Nearly every summer since, they have come to New York without security, rented a car and visited one of Mr. Moses’s landmarks, while reading the appropriate chapter in the biography, Mr. Caro said.

“These are some of the nicest days of my life, just the three of us,” Mr. Caro said. “I’m a lot older, but I felt like we were kids exploring New York.”

He described Mr. Rutte as a voracious reader who asks penetrating questions. “There is so much tension in Europe,” he said. “But if I ever met a person who could pour oil on troubled waters, Mark is that person.”

Well-known for riding his modest bicycle to work in his suit, and sometimes eating an apple while riding, Mr. Rutte’s image is meticulously curated, said Wilma Borgman, a Dutch journalist who has covered him for decades and recently co-wrote a book, “The Rutte Mystery.” He keeps his private life to himself.

“He doesn’t let anyone get close,” Ms. Borgman said. “Of all the people we interviewed, nobody ever went to his home. By Dutch standards, that’s exceptional.”

Mr. Rutte declined an interview request given the proximity to the NATO summit meeting.

After 14 years, he is leaving the Netherlands as a new government that includes Geert Wilder’s nationalist far-right Party for Freedom takes over.

There is criticism of Mr. Rutte’s own record on numerous issues, including a lack of new housing, consumers’ declining purchasing power and insufficient attention to the quality of education.

Mr. Rutte has also been accused of having been too slow to come to grips with the Covid-19 pandemic, too complacent about the earthquakes that resulted from the draining of a big natural gas field and too insensitive to an old scandal about child care benefits, when thousands of people were falsely accused of fraud.

With the challenge from Mr. Wilders, Mr. Rutte toughened his party’s stance on migration. At one point he urged what he called adherence to Dutch values, telling migrants: “Behave normally or go away.”

He broke up his last government because of disagreements on immigration, and then suddenly announced that he would not run again, leaving his party adrift and clearing the way to seek his new job at NATO.

Mr. Rutte has acknowledged his mistakes publicly and tried to learn from them, winning him broad leeway with the public and the nickname of “Teflon Mark,” said Matthijs Rooduijn, a political scientist at the University of Amsterdam. “The fact that he apologizes makes him a human being people can relate to,” Mr. Rooduijn said.

However, he added, “you can be of Teflon for a while, but at some point, after more than a decade, things do begin to stick to you.”

Mr. Rutte knew that “this was the moment to call it quits,” said Rem Korteweg, a senior fellow at the Clingendael Institute, a research institution in The Hague.

Jort Kelder became friends with Mr. Rutte in the late 1980s, in the youth organization of his party. They travel, sail and ski together. Mr. Kelder described his friend as “very energetic and almost laughably optimistic, but that is contagious.”

“When he is around, you feel guilty about getting angry about something,” Mr. Kelder said. “That would only disturb the party called life.”

At a 2020 European Union summit meeting to discuss the budget after Brexit, Mr. Rutte came prepared for a long night with a biography of Chopin and an apple.

Mr. Rutte’s view of the Kremlin was deeply affected by the downing of Malaysia Airlines Flight 17 over Ukraine in 2014, with 196 Dutch citizens among the 298 people killed by a Russian antiaircraft missile that had been provided to separatist forces by the Russian military. Two weeks after the Russian invasion of Ukraine, he described Mr. Putin as “coldhearted, brutal, merciless.”

Mr. Kelder remembers days of stress following the MH17 disaster. “It was the first time he admitted to being dog-tired,” he said of Mr. Rutte. “He had to call Putin at the most impossible hours. Stress, sadness and anger were fighting for priority.”

At NATO, a major part of Mr. Rutte’s task will be to increase military spending, as Mr. Trump always demands, while making European security less dependent on America — to try to “Trump-proof” the alliance’s support for Ukraine while also pacifying the man who could be president and who has remained noncommittal about keeping the United States in NATO.

Mr. Korteweg, the Dutch analyst, said Mr. Rutte is known for not making issues too complicated. “He’ll be good at keeping everyone together, and if Trump wins in November that will help,” he said.

Mr. De Groot, the former ambassador, said: “If he can’t bridge a new U.S. administration with Europe, I don’t think anyone can.”

Steven Erlanger reported from Berlin, Lara Jakes from Washington and Claire Moses from Amsterdam.