 Live from NPR News in Washington, I'm Korva Coleman. Today is the second day of the NATO summit in Washington. President Biden is telling NATO leaders the alliance must stay strong. NPR's Asma Khalid reports he says that's especially true in the face of Russia's aggression. Biden spoke at the historic site where the NATO treaty was first signed in 1949. Here they signed the Washington Treaty and created the North Atlantic Treaty Organization. The single greatest...