U.S. President Donald Trump on Wednesday wrapped up participation in the annual NATO summit, a gathering notable this year for an atmosphere that was far chummier toward Trump than the tension-filled meetings of his first term.

The leaders reaffirmed their “ironclad commitment” to NATO’s collective defense clause, Article 5. In recent years, Trump had sowed seeds of doubt about whether the U.S. — NATO’s most powerful member — would come to the aid of any ally under attack.

NATO leaders are gathering in the Netherlands for the start of a historic two-day summit that could unite the 32-member security organization around a new