NATO faces a crucial test of its credibility and future viability this week as leaders meet in Turkey, with new European defense spending targets under unprecedented scrutiny from the White House.
This week's summit, beginning Tuesday, will examine whether Europe can [turn bigger budgets into military power](https://www.cnbc.com/2026/07/01/europe-defense-stocks-rearmament.html) fast enough to keep President Donald Trump engaged, while preparing for a future in which Washington plays a smaller role in the continent's security.
Last year's summit at The Hague was seen as a [breakthrough](https://www.cnbc.com/2025/06/25/nato-allies-agree-to-higher-5percent-defense-spending-target.html) after allies committed to spending 5% of GDP on defense by 2035, including 3.5% on core defense requirements and 1.5% on broader security needs.
But this year's summit in Ankara is expected to move the debate from pledges to implementation. This includes questions about procurement, industrial capacity, support for Ukraine and the political architecture of what the Trump administration has called "NATO 3.0."
"This is really the NATO summit where NATO goes from burden sharing to burden shifting," Ulrike Franke, senior policy fellow at the European Council on Foreign Relations, told CNBC.
The summit also comes as NATO faces pressure to maintain its support for Ukraine and adapt to a battlefield shaped by rapid technological development in drones, air defenses and industrial capacity.
Here are five big questions facing NATO leaders.
European governments have broadly accepted that they must spend more, produce more and take on greater responsibility for their own security, following pressure from the White House.
But NATO has been structured around U.S. power for 77 years, making the issue as much a political question as a military one, said Max Bergmann, director of the Europe, Russia and Eurasia Program at the Washington-based Center for Strategic and International Studies.
If Washington pulls back, even without leaving, Europe faces a tougher question, he told reporters at a press briefing last week — how to organize defense without the U.S. at the center.
NATO Secretary General Mark Rutte has focused on keeping Trump engaged while moving burden-shifting plans forward. But Bergmann said there has been little discussion of a "plan B" if the U.S. decides it does not want to remain deeply involved.
For Europe, Franke said, another priority is clarity. If Washington intends to withdraw forces, assets or capabilities, allies need a roadmap and a timeline. That may be difficult with Trump, whose approach to allies has often been unpredictable.
Europeans will also be keen to put on a unified front publicly, particularly over defense spending, according to Franke. Spain and France have already faced criticism over their defense budgets. Meanwhile the U.K. and France face serious fiscal constraints despite recognizing the need to do more.
NATO's spending push has already shifted momentum in Europe's defense sector. Poland, the Baltic states, and Nordic countries have moved fastest, reflecting their proximity to Russia. Larger economies have moved more slowly, however, constrained by fiscal pressure and domestic politics.
"Now there's money in the system, but we need to be able to spend it," Franke said. "Europe needs to be able to produce things."
Europe's defense industry remains fragmented and constrained by supply chains, bureaucracy, labor shortages and years of underinvestment. Joint procurement could, in theory, lower costs, improve interoperability, and create scale. In practice, governments still want contracts, jobs, and tax revenue at home.
Franke pointed to Franco-German defense projects as an example of how national political incentives can slow cooperation, even when joint production makes strategic sense.
Ukraine is expected to be central in Ankara, with debate focused on long-term military support, Kyiv's own defense industry and what NATO can learn from the country after more than four years of full-scale war.
It comes as Russia suffers heavy losses on the battlefield. "The data indicates [that] the Russians are performing terribly in 2026," said Seth Jones, president of the Defense and Security Department at CSIS, citing rising casualty rates and loss of ground.
Kyiv has also stepped up long-range drone and missile strikes inside Russia, [targeting energy](https://www.cnbc.com/2026/06/29/putin-russia-fuel-shortages-ukraine-drone-strikes.html), military and logistics infrastructure, demonstrating the progress Ukraine has made in developing domestic strike capabilities.
Franke said NATO needs to stop seeing Ukraine only as a recipient of Western aid. Kyiv is now a source of military innovation, particularly in drones, counter-drone systems and battlefield data on how to fight Russia.
"Ukraine has the cards in drones and counter-drone systems," Franke said.
That could shift the NATO conversation from how the alliance helps Ukraine to how Ukraine helps NATO prepare for modern war.
The summit follows months of tension between Washington and European allies, including Trump's frustration over what he viewed as insufficient European support during the Iran conflict.
Franke said Iran could feature in Ankara. This could include debate over potential European contributions to maritime security or any peace arrangement, including minesweeping efforts. But she said such contributions are likely to be limited and partly symbolic, with Europeans still not fully aligned with Washington's approach.
Franke said European unity will matter if Trump singles out countries over spending, though that is difficult when threat perceptions vary widely across Europe.
There is also a question of future arrangements. NATO summits were not traditionally annual events, but they have been held every year since Russia's full-scale invasion of Ukraine. Bergmann said it would not surprise him if this were the last NATO summit of Trump's presidency, amid uncertainty over a tentative Albania summit next year and the 2028 U.S. election calendar.
That possibility could raise the stakes. If this summit is a "last hurrah," the message Trump chooses to send at this NATO summit could matter well beyond Turkey.
Turkey's role as host adds another layer of complexity.
Like previous host countries, Turkey is likely to use the summit to put its own security concerns and defense industry on the agenda.
For President Recep Tayyip Erdogan, a successful summit would likely demonstrate Turkey's centrality, avoid a major diplomatic breakdown and strengthen Ankara's case for access to defense procurement as European military spending rises.
"Defense procurement [and] legitimization of the regime are probably the core goals from Turkey," Bergmann said, noting democratic backsliding under Erdogan.
Turkey may also worry about being excluded as the EU channels more defense spending toward European producers, he said, adding that because Turkey is in NATO but not the EU, access to future contracts and joint projects could become a priority.
As NATO tries to keep the U.S. engaged, arm Europe faster and sustain Ukraine, Turkey will likely be pressing its own case: any new European security architecture still needs Ankara at the table.