His response was chilling to many in Europe.

"Well, I think it's common sense, right?" Trump said, interrupting the reporter asking the question. "If they don't pay, I'm not going to defend them."

A new Trump presidency and a war on European soil have pushed Germany — a country that for the better part of the past two decades has spent between 1% and 2% of its gross domestic product on its beleaguered military — to take the big step of changing its constitution to free up the money to spend more.

Two months after Trump's comments, incoming German Chancellor Friedrich Merz gave what many observers saw as a historic speech to parliament.

"Building up our military is our top priority," said Merz. "From now on, the federal government will provide the military with as much money as it needs to ensure it becomes Europe's strongest armed force. We are Europe's most populous country and Europe's biggest economy, and nothing less should be expected from us. Our partners not only expect this — they demand it." Changing the national DNA

"So this sense of urgency made a decision possible that was unthinkable before," says Claudia Major, senior vice president overseeing trans-Atlantic security initiatives at the German Marshall Fund.

She says the German government's plan over the next decade to spend 3.5% of its GDP on defense — a percentage equal to that of the United States — is a bold and surprising move.

"But we also know that the DNA of a country — the way our country and the citizens behave in defense, how they see military force, how they see their armed forces — takes years and decades to change," she says. "Normally we say it takes a generation."

Germany won't cut social programs for defense. A $117 billion special fund and a 2025 constitutional change suspending what's known in Germany as the debt brake — or balanced budget spending cap — let it borrow separately from the normal federal budget for defense and infrastructure. This will enable close to $400 billion in defense spending through 2029 without affecting core budgets — for now.

Some parts of German society, especially businesses in the defense sector, are more ready than others for this historic change.

In an industrial park outside Munich, a worker completes a series of tests on a drone that has just come off the assembly line at Quantum Systems. The aircraft, called the Vector, is the company's bestselling drone, says Director of Operations Alexandra Rietenbach. "It's our dual-use product," she says. "It's used on the one hand in Ukraine. It's also used for the German armed forces. It also is used in Europe in general, in different organizations like police, like border control." Quantum Systems’ chief sales officer, Martin Karkour, holds one of his company’s bestselling drones, the Vector, at the company’s headquarters outside Munich.

Photo: Quantum Systems' chief sales officer, Martin Karkour, holds one of his company's bestselling drones, the Vector, at the company's headquarters outside Munich. Quantum Systems' sales are up due to its role in providing Ukraine's military with drones to defend the country against a Russian invasion. Rob Schmitz/NPR

Rietenbach says Ukrainian troops rely on the Vector and the company's other drones to gain a military advantage against invading Russian troops. As a result, Quantum Systems' chief sales officer, Martin Karkour, says sales have picked up. "We are doubling each year in terms of sales and revenue, and also in terms of head count," he says.

Buying weapons is the easy part

While business for defense companies like Quantum Systems looks promising, Germany's defense spending boost might take some time when it comes to rebuilding a culture of military service.

At a job fair in Berlin, the Bundeswehr, Germany's armed forces, has set up a recruiting booth staffed by Marco Mann, who has recruited at fairs like this for 18 years. He says the German public's attitude toward its armed forces is improving.

"I never used to hear 'Thank you for your service' from others, but that's starting to change," he observes. "People now are thanking us for our support of Ukraine, thanking us for being here — it's a nice change."

Germany is the third-biggest provider of military support to Ukraine, after the U.S. and the United Kingdom. It provides weapons systems prized by Ukraine, including Leopard 2 tanks, the IRIS-T air defense systems, ammunition and artillery shells. Germany has also welcomed 1.2 million Ukrainian refugees, according to the German Interior Ministry.

Abdul Rehman Saeed is one of the job seekers at this fair. He's 32, was born in Pakistan, has lived in Germany for a decade and is a German citizen. He says he's interested in joining the Bundeswehr as an IT specialist. "I think it's not about going to the battlefield, but as a preemptive measure to actually help them if they are trying to do something and might need someone with a cybersecurity background, because everything is now cyberwar," he says.

He says Germany has given him a free education, affordable health care and many other opportunities. "I feel personally responsible to provide back to this society because Germany gave me a life I wanted," he says.

In return, he says, if he gets job security, then joining the Bundeswehr is a "win-win." And as the Bundeswehr has more money and begins the challenging process of recruiting more personnel, it hopes to gain prestige, both domestically and internationally.

Esme Nicholson contributed to reporting from Berlin.