It was apt that President Trump departed for a NATO summit under deep rain. The alliance’s meeting in London, after all, comes during a time of escalating tensions between America and its European allies. But although the 29-member alliance faces real problems, it continues to offer instrumental service to American interests.

NATO is the cornerstone of the American-led international order. Yes, it’s absolutely true that an unfair burden of American blood and treasure have underpinned that order since 1945, making the world freer, safer, and wealthier. But beyond the moral import of ensuring people can choose their leaders and set their destinies — the advancement of freedom being the uniquely historic exhibit of American hegemonic power — this condition of peace has directly benefited Americans.