NATO leaders convening Wednesday in the Netherlands were prepared to offer President Donald Trump a major win by boosting their defense spending targets.

But comments he made while flying to the conference were raising fresh concerns about his commitment to the alliance’s core principal of collective defense.

The split dynamic — where leaders tailored their gathering to appeal to Trump, even as he questions the core provision of membership — made for a charged atmosphere as the conference was getting underway at The Hague.

Trump vowed to stand alongside fellow NATO nations a day after hedging in his support for the alliance’s Article 5 pact, which says an attack against one member is an attack against all.

“We’re with them all the way,” Trump said. “If you take a look at the numbers, we’re with them.”