Trump deemed the summit in The Hague this week a resounding success, while taking aim at Spain's refusal to commit to dramatic spending increases for defense.

President Trump on Wednesday laid into Spain for expressing reservations about an increase in NATO defense spending, drawing his ire during his press conference at the alliance’s summit on

Mr. Trump had been eager to celebrate his success at NATO and revel in the fact that he had conducted an attack that none of his predecessors had dared to launch. His view was backed up by Mark Rutte, the secretary general of the alliance, who wrote Mr. Trump a private message thanking him for his “decisive action” in Iran.