The alliance between the United States and rest of NATO has begun fraying in recent years—at the very moment when the threat posed by both Russia and China is surging. NATO was founded in 1949 on a promise of mutual self-defense. But U.S. President Donald Trump has raised new questions about America’s commitment to that promise, heightening fears across the alliance.This week on And Now the Hard Part, we trace the roots of the problem and talk about how to fix it.“My concern is simply that if we ever had a catastrophic moment or a security crisis, do the rest of the members of NATO feel secure enough in the way the United States supports them that they would support us if we needed them?” said the Brookings Institution scholar Victoria Nuland, a former assistant secretary of state and the guest on our show this week.“It depends on how long this seeding of doubt about our own reliability continues.”