Opinion | NATO Has to Change. Here’s How.

What would Ike say now?

Gen. Dwight Eisenhower, NATO’s first supreme allied commander Europe, felt strongly that his mission was to get Europeans “back on their military feet” — not for American troops to become the permanent bodyguard for Brussels and Berlin.

“If in 10 years, all American troops stationed in Europe for national defense purposes have not been returned to the United States,” he wrote of NATO in 1951, “then this whole project will have failed.”

But as leaders of NATO allies gather in Washington on Tuesday for the alliance’s 75th anniversary, some 90,000 U.S. troops are stationed in Germany, Italy, Britain and elsewhere, making up a significant portion of the 500,000 NATO troops on high readiness.

America’s outsize presence comes not just in the form of troops. Of the $206 billion in military and nonmilitary aid allocated to Ukraine by countries around the world, $79 billion has come from the United States, according to the Ukraine Support Tracker database. Since about 1960, the United States’ share of allied G.D.P. has averaged roughly 36 percent, while its share of allied military spending has been more than 61 percent, according to a Cato Institute report. The supreme allied commander Europe has never been a European.

It is now becoming increasingly clear that Europeans need to shoulder more responsibility for their own defense. That’s not just because Donald Trump and an isolationist wing of the Republican Party complain bitterly about having to defend wealthy countries that, by the way, can afford social safety nets that America can only dream of because they don’t spend as much on their militaries. It’s also because U.S. officials are becoming more focused on the challenges posed by China, which will require an increasing amount of attention and resources in the years ahead, especially given the growing cooperation among China, Russia, North Korea and Iran.

The United States simply can’t do everything everywhere all at once, by itself. The future requires well-armed, capable allies. The indispensable nation has to be a bit less indispensable.

Regardless of who wins the U.S. election, European leaders understand that they need to contribute more, Foreign Minister Espen Barth Eide of Norway told me. During his recent trip to Washington, he said Republicans relayed that Europeans have to take much more responsibility for the war in Ukraine because the United States has “bigger fish to fry.”

It’s starting to happen, but not nearly as quickly as it should. The NATO summit will no doubt celebrate the fact that 23 NATO members are expected to spend at least 2 percent of their G.D.P. on defense, up from just three members that met that threshold a decade ago. But it’s stunning that nearly a third of NATO’s 32 members still fell short of that spending goal, which was agreed upon in 2014. If Russia’s full-scale invasion of Ukraine and Mr. Trump’s not-so-subtle threats to abandon freeloaders haven’t convinced them to pony up more for their own defense, it’s hard to imagine what will.

After all, European reliance on U.S. troops runs counter to what many Europeans and Americans say they want. Majorities in the United States, Britain, France and Germany believe Europe should be “primarily responsible for its own defense while aiming to preserve the NATO alliance,” according to a recent survey by the Institute for Global Affairs. Only 7 percent of German and 13 percent of French respondents felt that United States should be primarily responsible for Europe’s defense.

Europe’s dependence on the United States is engendering growing unease on the continent. Finland’s former president Sauli Niinisto has called for a “more European NATO,” and President Emmanuel Macron of France has warned that “however strong our alliance with America is, we are not a priority for it.”

So why does this dependence persist?

Part of the reason is human nature. Why would allies invest in defense if Uncle Sam always picks up the tab? But another reason is structural. When NATO was created, European allies were just emerging from devastating wars that left them suspicious of — and even hostile to — one another. Somebody had to herd the cats.

That’s how the U.S. role in NATO changed from that of temporary helper to permanent protector. At first, NATO was like a policeman watching over a construction site; the alliance went hand in hand with the Marshall Plan. If Americans were going to help rebuild Europe, they had to make sure that Moscow didn’t steal their investment.

But by the 1960s, it had become obvious that U.S. troops wouldn’t be leaving anytime soon. The Soviet Union had swallowed up much of Eastern Europe, including the eastern part of Germany. That made West Germany key to stopping the Soviets, but few in Europe could stomach the idea of a strong German military after what had happened under the Nazis. So the Americans stayed put and protected Germany with their own troops and nuclear umbrella.

“The present system did not take shape because America had set out to become a kind of empire,” Marc Trachtenberg, a political scientist at the University of California, Los Angeles, who has written extensively about the Cold War, told me. “The system came into being because U.S. leaders realized by 1961 that there could be no purely European solution to the European security problem.” The Americans, he said, were stuck in Europe.

Once Washington realized it couldn’t leave, it started calling the shots. “We are bound to pay the price of leadership,” McGeorge Bundy, President John F. Kennedy’s national security adviser, said in 1962. “We may as well have some of its advantages.”

That meant juicy defense contracts for American firms, which became a powerful financial incentive to keep a big footprint in Europe. It’s one reason Poland buys American tanks that are too heavy to cross Polish bridges and Romania buys fighter jets that are extremely expensive to operate and maintain. The U.S. military industrial complex profits from dependency. About 63 percent of the military equipment that European Union countries purchased in 2022-23 came from the United States.

At the end of the Cold War, Europeans tried to wean themselves off U.S. military might. In 1998, Prime Minister Tony Blair of Britain and President Jacques Chirac of France attempted to create a European security system capable of acting on its own. But Secretary of State Madeleine Albright nipped that in the bud in a speech that warned against diminishing NATO’s role, duplicating NATO’s efforts and discriminating against NATO members that weren’t in the European Union.

In 2017, 23 European countries started the Permanent Structured Cooperation on Security and Defense to work together on practical projects such as cyberdefense. That, too, got a negative reaction from the Trump administration, which warned against excluding American firms.

It’s no wonder that today Europe lacks the capacity to deploy the soldiers and equipment that NATO needs to defend its members, especially when it comes to specialized units such as air defense, intelligence and surveillance. John R. Deni, the author of a new report on NATO readiness, told me that NATO planners routinely come up short when they seek contributions of sophisticated systems, partly because so much has already been sent to Ukraine. “There is just not enough to go around,” he said. “There are still troubling gaps.”

Luckily, some European leaders are treating this with the urgency it deserves. At the summit, NATO allies are expected to endorse a new defense industrial pledge to scale up the production of weapons and ammunition. But NATO’s procurement plan relies heavily on American arms makers. That clashes with the new European Defense Industrial Strategy, rolled out by the European Commission in March, which envisions spending half of its military procurement budget on items produced in Europe by 2030. Once again, cats need to be herded. There’s a dire need for both institutions to get on the same page.

If they do, it will be a great step forward for Europe’s ability to assist in its own defense. In the past, Americans might have sensed a threat to their authority and sabotaged this effort to build up a European defense industry. But today, Americans, who are also struggling to ramp up their own industrial defense production, need all the help they can get.

“A stronger Europe means a stronger NATO and ultimately a more equal partnership between the U.S. and Europe,” said Rachel Rizzo, nonresident senior fellow at the Atlantic Council’s Europe Center. “You want a peer relationship. You don’t want a client.”

Europeans are finally stepping up, as General Eisenhower dreamed they would. Let’s not stand in their way.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.

Follow the New York Times Opinion section on Facebook, Instagram, TikTok, WhatsApp, X and Threads.