BRUSSELS — NATO’s glassy headquarters was still standing Thursday, a day after the end of a whirlwind summit with President Trump that had threatened to blow it away.

On substance, in fact, the meeting of NATO leaders that took place just outside London was an almost normal gathering, despite fears that Trump or one of his brothers in unpredictability, French President Emmanuel Macron or Turkish President Recep Tayyip Erdogan, could derail the proceedings.

Trump stormed into the meeting summit as a disrupter and rushed out earlier than planned after fellow leaders were caught on camera laughing about his erratic style. In between his entrance and exit, though, the alliance approved a list of new measures that heartened policymakers who had been battered by years of uncertainty from the White House.

“What we prove today is that NATO delivers on substance,” said NATO Secretary General Jens Stoltenberg, a usually subdued Norwegian leader who allowed himself a half grin — perhaps of relief — after he steered the group of 29 squabbling heads of state toward an almost normal conclusion. At NATO, he said, “the rhetoric is not always excellent, but substance is perfect.”

At NATO headquarters Thursday, diplomats and military officers walked in and out of the lobby Starbucks joking and ordering celebratory lattes. Ambassadors were back in their offices after the migration to London, where the summit was held at a 18th-century estate outside the city.

They pointed to a list of achievements that was summarized in a dry, two-page declaration that leaders signed on to at the meeting — not scintillating literature but nevertheless important in giving a political endorsement that sets vast bureaucracies in motion to fulfill the directions.

NATO set up a large new rapid-response force to be able to speed quickly across Europe if ever there were a conflict. They committed to keeping their next-generation cellular networks secure, a U.S. priority amid fears that China’s Huawei telecommunications company could help Beijing get access to European networks as the continent upgrades to speedy 5G connections. They agreed to start thinking about the implications of China’s growing strategic power. And Turkey signed off on updated military plans to defend Eastern Europe against Russia that it had been holding up for months because it was angry that fellow members were working with Kurdish forces in Syria that Ankara views as a threat.

And Macron — who last month declared that NATO was suffering “brain death” as it catered to Trump’s single-minded focus on defense spending — was placated by a promise to set up a committee to reconsider the alliance’s broad strategic vision.

“We were expecting worse,” said one senior NATO official after the meeting, speaking on condition of anonymity to discuss the closed-door meeting, which lasted three hours and in which most leaders hewed closely to their scripted talking points.

That may have been a touch boring — but boring might be good in the Trump era, given the alternatives, the official said, although some were waiting a full 24 hours after Trump’s departure to fully exhale, given his past track record of blowing up summits even after he has left.

At a 2018 meeting of the Group of Seven leaders in Canada, for example, as Air Force One pulled away, Trump withdrew his signature from a declaration in a fit of pique after feeling slighted by his hosts.

This time, though, Trump on Thursday portrayed the whole visit as a success, despite his early exit.

“Tremendous things achieved for U.S. on my NATO trip. Proudly for our Country, no President has ever achieved so much in so little time,” he tweeted.

Among the Eastern European countries most vulnerable to Russia, which has been the alliance’s primary focus in recent years, there was still some nervousness about the outcome of the meeting. But the unease had less to do with Trump and more to do with Macron, who has declared he wants to reboot a dialogue with the Kremlin and that terrorism, not Russia, ought to be the primary focus for the alliance.

At the meeting, Macron tried to signal to Eastern European leaders that he did not plan to compromise their security in the name of better relations with Moscow.

“I’m under no illusions,” Macron said afterward. “But if we want to move forward in fostering stability in Europe, we need to move forward with that dialogue” with Russia.

On Monday in Paris, Macron and German Chancellor Angela Merkel are scheduled to bring together Russian President Vladimir Putin and Ukrainian President Volodymyr Zelensky for the first time. And some policymakers remain uncomfortable about what could unfold.

“The French and Germans are pushing on Ukraine. There’s no doubt about it,” said a senior NATO diplomat, speaking on the condition of anonymity to discuss internal alliance discussions. “We’re concerned that they’ll try to twist Zelensky’s arm to accept solutions that are unacceptable.”

Zelensky has declared that he wants to achieve peace in eastern Ukraine, where Russian-backed separatists have been waging war since 2014. Ukraine’s Eastern European partners fear that he could be pressured into accepting Russia’s annexation of Crimea or otherwise pushed into making a deal that would be politically unacceptable at home and that could embolden Russia to be aggressive in other vulnerable countries in the future.