What another Trump presidency would mean for NATO

Ivo Daalder, former U.S. ambassador to NATO, is CEO of the Chicago Council on Global Affairs and host of the weekly podcast “World Review with Ivo Daalder.”
As a former United States ambassador to NATO, I am often asked whether I think former President Donald Trump’s reelection in November would mean the end of NATO.
The answer I give is: Yes and no.
Yes, Trump’s election would mean a fundamental change for NATO whether he decided to withdraw from it or not. But no, the alliance wouldn’t necessarily come to an end.
Let me explain.
Trump’s animosity toward NATO — indeed, to all of America’s security alliances around the world — is well known. When he ran for president the first time, he frequently exclaimed that NATO “is obsolete,” and once in office, he repeatedly threatened to withdraw from it. “I don’t give a shit about NATO,” he yelled at his then-National Security Advisor John Bolton during a heated debate.
Later, Trump informed European Commission President Ursula von der Leyen, “You need to understand that if Europe is under attack, we will never come to help you and to support you,” according to an EU official present at the meeting. He then added, “By the way, NATO is dead, and we will leave, we will quit NATO.”
And while Russia’s full-scale invasion of Ukraine in 2022 reminded many of NATO’s value and importance — as well as that of the U.S. commitment to European security — Trump learned a different lesson. Calling Russian President Vladimir Putin “smart,” “savvy” and “a genius,” he claimed that if given the chance, he could end the war in “one day” by cutting off all U.S. assistance to Ukraine and telling Kyiv to make a deal with Moscow.
Today, Trump’s dislike for NATO remains undiminished, and were he to return to the Oval Office, there’s no doubt it would continue.
Moreover, no one should put much faith in the recently enacted Congressional edict meant to prevent a president from withdrawing from the alliance without Congress’ consent either. No one can force an American president to defend another country with the full force of the U.S. military — not even Congress.
Legally, the U.S. (or any other NATO member, for that matter) is merely obliged to take “such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.” In other words, each member is left to decide for itself whether and how to act in case of an armed attack on an ally. And even that provision, in Article 5, is only binding after all NATO members agree to invoke the commitment.
What makes a security alliance effective isn’t some legal diktat, however — it’s the trust that allies have in each other, that they will come to each other’s defense, and the credibility of that commitment in the eyes of their adversaries. Legally binding commitments can solidify that trust, but they can’t sustain it on their own — let alone build it.
But whether Trump would actually withdraw from NATO as many fear — which any treaty ally can do under Article 13 — is beside the point. The simple fact is that his reelection would be seen as a fundamental repudiation of the trust NATO allies have placed in the U.S. to come to their defense in case of an armed attack. More so, now that the possibility of such an attack looms large in Europe after Russia’s brutal war in Ukraine. Neither allied leaders nor their publics would have any confidence that a Trump-led America would come to their aid.
This reality wouldn’t necessarily spell the end of NATO, though it would turn it into a fundamentally different alliance than the one that’s existed for the past 75 years. NATO wouldn’t end even if he were to formally withdraw — it would just have one less member.
Of course, the U.S. isn’t like every other NATO member — it’s the true backbone of the alliance. Starting with General Dwight D. Eisenhower, its supreme commander has always been American. The U.S. military also accounts for a good part of NATO’s overall capability, and its armed forces constitutes the nucleus around which most NATO allies have built their own militaries. More than 100,000 U.S. land, air and naval forces are currently deployed throughout Europe in direct support of NATO.
Moreover, the U.S. nuclear arsenal, including weapons deployed in Europe for use by allied air forces, “are the supreme guarantee of the security of the alliance.” And while France and Britain possess substantial nuclear capabilities, their willingness and ability to extend the nuclear umbrella to all of their allies is uncertain and untested.
Still, NATO would remain a potentially formidable military alliance even without the U.S. Its members include most of the countries in Europe, plus Canada, and the organization possesses processes, procedures and programs for collective defense that are highly developed and potentially very effective.
Whether that potential would be translated into reality would, of course, mostly depend on the members that remained. And a NATO without the U.S. wouldn’t be nearly as effective as one with it. It would also be a less credible deterrent to Russia and other adversaries.
NATO might not end with Trump’s election, but the alliance would be substantially weaker without a credible American partner, making European security far more precarious than necessary or desirable. And it’s not only Europeans that would have to bear the costs — Americans would too.