President Donald Trump prefaced his arrival to the annual summit meeting of the NATO military alliance in The Hague by telling reporters Tuesday morning, “NATO was broke, and I said, ‘You’re going to have to pay.’”

NATO members agreed on Sunday to hike their defense spending to 5% of their gross domestic product (GDP) by 2035, a marked increase from the 2% commitment that’s been standing since 2014. Trump previously demanded allies double their spending goals to 4% of GDP in 2018. Experts tell Fortune that while the effort to collectively pledge billions of additional dollars toward defense spending over the next decade will be met by some countries, it may not be feasible for others.

The pact details a pledge of 3.5% of GDP to be put toward “core” defense, with 1.5% of GDP funneled to security-related investment, “including in infrastructure and resilience,” according to NATO’s website. To put the percentages into perspective, NATO estimates the UK spent 2.33% of its GDP, or $82.1 billion USD, in 2024.

Experts say the Sunday agreement may be more of a political play than a promise, as European countries aim to appease Trump and reinforce the alliance amid geopolitical turmoil.

“Five percent would be just crazy for Europeans,” Liana Fix, a Council on Foreign Relations fellow for Europe, told Fortune. Though Fix says 3.5% of GDP is a realistic estimate for many member countries’ needs.