The current crisis is different. Gathering this week in Washington for a big 75th birthday celebration, NATO has never had more clarity and urgency about its mission. There should be no existential doubts: The collective of 32 countries is there to defend the Western flank of democracies against an aggressive Russia, mobilized for a long war, and its most important ally and leader of the new axis of “resistance” in Beijing.

Yet Washington pharmacies might want to stock up on Xanax. NATO’s mission may be clear and urgent, but the political realities are harsh. The ascendant former President Donald Trump and his advisers are drawing up plans that would upend the alliance, as Michael Hirsh detailed in these pages. In Europe, politicians friendly to Russia and skeptical-veering-hostile on NATO are doing well, and the alliance and governments are making plans for different management in Washington.

Those are, at heart, details. NATO’s bigger challenges go beyond who holds power in the White House or any other capital. Looking ahead, the U.S. under any administration is likely at the limit of what it can do for Ukraine and will want Europe to step up and make better use of its fatter defense budgets. America’s attention is back on the Middle East and China, and NATO will have to fit into those plans somehow or lose relevance in Washington.

Throughout this week, you’ll hear that NATO is the world’s most successful military alliance in history. That���s not wrong. Now, how do you keep it?

NATO’s outgoing secretary general, Jens Stoltenberg, has had this question top of mind for a decade. Meeting with him the other day, I asked what he considers his biggest achievement. He answers immediately: “That I have been able to keep this alliance together.”

Stoltenberg, a Norwegian, hails from a nation prone to existential musings but not hysteria or hyperbole. A former prime minister who was interested in finance and climate change, he was picked by Germany’s Angela Merkel in early 2014 to improve NATO’s worsening relations with Vladimir Putin. How bitterly funny in retrospect. His father, a former foreign minister, warned him that Brussels and the NATO job were “boring.” That too. By the time he took over later that year, Russia had annexed Crimea and started a proxy war in eastern Ukraine. In those early days, Stoltenberg looked out of depth and people who know him say he was struggling in the role.

Putin’s full-on invasion of Ukraine in 2022 forced the allies to mobilize for a land war in Europe. That unified NATO. Stoltenberg’s political education at NATO came earlier, courtesy of Donald Trump. The Europeans take advantage of the U.S., spending too little on defense – that’s a Trumpian constant. At the 2018 summit, a frustrated Trump threatened to pull the U.S. out of NATO if the allies didn’t pony up. It was “dramatic,” says Stoltenberg, deadpan. Looking back, he offers a lesson for his successor, the former Dutch Prime Minister Mark Rutte, who takes over in October, and other new leaders on how to deal with possibly the next U.S. president: “Engage with him, sit down with him, spend time with him,” he says.

The Stoltenberg playbook had him also embrace the Trump critique about European spending (“an absolutely valid point,” he tells me) that happens to be what every American president going back a quarter-century has said. On his last visit to Washington in June, Stoltenberg announced that 23 NATO allies met or exceeded the defense spending target of 2 percent of GDP; a decade ago, only four members did. The alliance set that bar in 2014 under Barack Obama. Stoltenberg convinced Trump the steady improvement had been his doing. His colleagues at NATO used to jokingly refer to him as the “Trump whisperer.”

“Unlike most West Europeans, he doesn’t freak out about Trump,” says Kurt Volker, a former U.S. ambassador to NATO who was Trump’s Ukraine envoy. “You don’t know what the Trump policy will be. Neither does he.”

In another era, the political threats to NATO came primarily from Europe. From the French above all, because they saw the alliance as too American. Now Americans have turned skeptical of NATO. Though he is on his way out, Stoltenberg offers a template for how to make the case for NATO.

“NATO makes the U.S. safer, the U.S. stronger and actually NATO creates a market for U.S. equipment,” he says. Stoltenberg has spent enough time on Capitol Hill to know what arguments resonate. His background in finance gives him a feel for numbers. In the last two years, he points out, the U.S. has signed $140 billion in defense contracts with European countries due to the increased spending. The alliance has stood up half a million combat-ready men and deployed eight new multinational battle groups into the frontline Baltic and Black Sea states — both controversial goals that seemed hard to attain when adopted by NATO under his watch. Though the U.S. continues to account for nearly 70 percent of NATO military spending compared to half its combined economy, non-U.S. defense expenditures grew by $64 billion in 2024, the equivalent of adding France and Norway’s combined defense budgets to the alliance. “Quite serious money,” as another senior NATO official in Brussels says.

Ukraine is the litmus test. Parts of the American and European right — and the left too in France and Germany, but they’re not as relevant — want to cut a deal with Putin and certainly cut support for Kyiv. As Hirsh reported, Trump’s aides have drawn up an offer: Promise Russia that Ukraine will never join the alliance and give Moscow Ukrainian territory in return for an end to the fighting. On a self-assigned peace mission, Hungary’s Prime Minister and Trump buddy Viktor Orbán shook the indicted Russian war criminal’s hand at the Kremlin just a few days ago before continuing on to China.

This is awful mood music for Ukraine. What’s the counter to this emerging view on the political extremes in the alliance? Stoltenberg offers China. Ukraine isn’t a distraction, he argues, but part of the struggle with Beijing. North Korea, Iran and China are fighting in Ukraine with Russia by backing Putin with arms and other support. They want the U.S. and NATO to fail in Ukraine, he says. “If Putin wins in Ukraine, that’s a big win for [Chinese President] Xi. We should not allow them to win.”

“There’s the idea that we have to distinguish between Asia-Pacific and Europe,” Stoltenberg continues. “Our security is not regional, it’s global. It matters what happens in Europe for the Asia-Pacific, and it matters for the Asia-Pacific what happens in Europe. And therefore, it matters for the United States.”

The idea of a “global” NATO was batted around after 9/11. Some at the time wanted Israel in the alliance. The AUKUS group that brings the U.S. together with Britain and Australia in the Pacific to respond to China’s rise is a more recent example of extending the “Western” alliance into the Pacific. Rutte could put his predecessor’s “Security is not regional, it’s global” slogan above the entrance to NATO’s headquarters.

In reality, the alliance’s future will be decided a lot closer to home. The military transformation that took place in Stoltenberg’s decade — almost certainly the most consequential tenure of any secretary general — was real, even as he admits, “of course, we could have done some of these things faster.”

That’s Norwegian understatement. The Ukraine war has exposed huge shortcomings. European and American stockpiles and industrial capacity are woefully inadequate. The Europeans lack sufficient air defenses and long-range strike power. Most European militaries lack the “mass” of men and brigades needed to fight a land war and the logistics and technology to work well together. Spending was too low, but priorities were elsewhere, too — on counterinsurgency and global deployment, not territorial defense. “This is a different military task than they had in the last 30 years,” says the senior NATO official.

Europe’s military complex is at last coming to life. Poland’s defense budget is above 4 percent of its GDP, the highest in NATO. Denmark doubled its spend in 12 months, to 2.3 percent of GDP. NATO’s newest members, Finland and Sweden, brought in two of the most capable and advanced militaries on the continent. Contracts for new and more weapons are coming through, but that will take years to get going. Should the U.S. cut back on Ukraine military aid next year and European stockpiles remain too thin, I heard one EU minister float the good idea of using European funds to buy American armaments for delivery to Kyiv.

All the while, Russia is massively expanding production. Europe and even the U.S. both have a ways to go to truly get on a war footing. In the Cold War, budgets were in the 3-5 percent range. With the world as hot as it is now, the 2 percent target should be the floor, not the aspirational goal. Europe had been getting its security and NATO’s Article 5 mutual defense protections on the cheap for most of this century.

“NATO is stronger than ever militarily,” Anders Fogh Rasmussen, the former Danish prime minister who was NATO’s secretary general from 2009 to 2014, tells me. “But what I think it lacks is courage and strategic vision.”

Rasmussen saw through Putin a decade ago and prompted Merkel to look for a dovish NATO boss. Now in the private sector, he thinks that the alliance has to provide more robust military support for Ukraine and offer Kyiv a clear path to membership. Putin has caused trouble in places in Europe that are “gray zones.” As long as Ukraine, or Georgia, are denied their free choice to join the EU or NATO, they’ll be vulnerable. European history shows us how gray zones invite trouble and conflict. That’s the appeal to political courage and vision. At the same time, Rasmussen, who spends a lot of time in Washington and speaks to people from both parties, worries about the dangers of weakness: “Trump undermined NATO politically by publicly raising doubts about Article 5. He tempts Putin to test our resolve.”

The alliance should be prepared to deal with the politics as they come. Unpredictability is the new normal everywhere. Trump has no monopoly on that. The key to NATO’s future will be its ability to stay serious and follow through in the next years on the pledges to wake up to the new security realities in Europe and globally.

American critics of NATO tend to confuse the alliance with the United Nations. NATO was built to follow America’s lead, in America’s image — down to the bad food at its cafeteria and its penny-pinching. It has served America’s interests for generations. The case that it can continue to do so in this new era isn’t hard to make. It would have to be made in Europe, as well in the U.S., with words, budget spreadsheets and actions on the ground.