Mark Rutte came prepared for his latest visit to Washington in late June.

As Donald Trump complained about European allies and their reluctance to support the United States during the war against Iran, the  NATO secretary-general responded with praise. Lots of it. And pointed to large display boards emblazoned with gold-colored headlines, one titled: "The Trump Trillion."

In front of the cameras, Rutte was in full pitch mode. "I want to show you what this president was able to achieve," Rutte told the press, highlighting an additional $1.2 trillion (€1 trillion) in defense spending by European allies and Canada since 2017, when Trump first took office.

Just days before a crucial NATO summit kicks off in Ankara on July 7, Rutte was doing what has become one of, if not his most, important tasks: keeping Donald Trump on board. The summit will bring together the leaders of NATO's 32 allied countries at a moment of growing uncertainty amid heightened tensions in the Middle East and Russia's ongoing war with Ukraine.

As the US reviews its military posture in Europe, many European governments are worried about how committed Trump remains to the security alliance.

Ankara summit aims to 'make a case for NATO'

Rutte's strategy to keep the alliance together is to flatter Trump, emphasize the benefits NATO brings to the US and highlight the efforts European allies have made to increase defense spending. The NATO chief wants to avoid public disputes in Ankara and showcase allied unity.

Claudia Major, a trans-Atlantic security expert at the German Marshall Fund think tank, told DW that worried leaders will be trying to send the message that the alliance is still strong — and looking "to please Trump and to make a case for NATO."

This may explain why Rutte — desperately looking for common ground — has placed defense production at the center of this year's summit.

He is expected to unveil what he calls a "defense industrial revolution," including tens of billions of dollars in new contracts and procurement deals for Europeans looking to boost weapons production.

Rutte's goal, said Major, is "to show that there is a market for the US industry and also to make an economic case in favor of NATO that Trump hopefully will find attractive."

US to keep 'close eye on allies' in Europe

Whether that approach will work remains unclear. "If we have learned one thing about the US president over the last one-and-a-half years," Major said, "it is that he can be very disruptive and it is difficult to predict what he is going to do."

That unpredictability was on display at a NATO defense ministers' meeting in Brussels on June 18, when Trump's defense secretary, Pete Hegseth, announced a review of American troop deployments and military posture in Europe.

Hegseth also delivered a blunt warning: "Our national defense strategy states clearly that we're going to incentivize and enable our allies to step up and do their part," he said. "So we're going to keep a close eye on allies who are not doing that, and who say no, or maybe, or wait and see when it matters most. It's a review that some countries will fail, and others will pass with flying colors."

The harsh tone caused some irritation among the assembled ministers. The review itself was expected — European governments have long anticipated a gradual reduction of the US role in Europe. Their concern is about how quickly that will happen.

German Defense Minister Boris Pistorius warned against creating military shortfalls during the transition. "It's about a road map. It's about a synchronized way of doing it," he said after the defense ministers' meeting. "The most relevant challenge is to avoid dangerous capability gaps."

Europe needs its own plan for managing this transition, said Major. "If the US decides that they no longer want to play a crucial role in Europe, Europeans have to step up — and they better do that quickly given the threat from Russia and the overall geopolitical fragility around Europe," she said.

Following US pressure, European NATO-allies and Canada increased defence spending by 20% in 2025 compared with the previous year in real terms.

Support for Ukraine high on agenda

An important part of the Ankara summit will also be to secure further support for Ukraine, including potential new billion-dollar funding pledges to strengthen the country's defense and security.

According to news agency AFP, NATO's European members and Canada will pledge to give Ukraine 70 billion euros ($80 billion) in military aid both this year and next at the upcoming Ankara summit.

But tensions persist among European allies about sharing the burden, with Rutte repeatedly calling for Ukraine aid to be distributed more evenly among NATO partners.

For Major, the central question of the NATO summit is not defense spending or procurement contracts, but political unity.

"If the summit displays political division, if there's open dispute, if the US president criticizes one ally for not spending enough, for not doing enough in the Iran war, this is weakening the political cohesion and with that also the military deterrence and defense message," she said.

But there is cautious optimism that the allies will stand together. At last month's G7 summit in France, Trump struck a far more cooperative tone and joined other leaders in backing additional pressure on Russia and President Vladimir Putin, including additional sanctions on oil exports and the banking sector.

German Chancellor Friedrich Merz took the outcome as a positive signal, saying it sent an important signal for Ukraine and set "a new tone in trans-Atlantic unity and determination."

"That may open up, perhaps for the first time, a chance for peace," he said.

NATO unity faces real test

NATO leaders are hoping for a similar outcome of unity in Ankara.

The summit declaration is expected to reaffirm Article 5, the alliance's mutual-defense clause, which states that an attack on one ally is an attack on all. And they are hopeful for maintaining language describing Russia as a long-term threat to Euro-Atlantic security — both key priorities for European allies.

But deterrence only works if that promise is believable. And that is why unity is the real test facing NATO in Ankara.

Edited by: Martin Kuelber, Andreas Illmer