What does a massing of Russian troops on the Ukrainian border mean? And could this conflict be defused yet by diplomacy? Guest: Slate’s Fred Kaplan, author of The Bomb: Presidents, Generals, and the Secret History of Nuclear War.  If you enjoy this show, please consider signing up for Slate Plus. Slate Plus members get benefits like zero ads on any Slate podcast, bonus episodes of shows like Slow Burn and Dear Prudence—and you’ll be supporting the work we do here on What Next. Sign up now at slate.com/whatnextplus to help support our work. Learn more about your ad choices. Visit megaphone.fm/adchoices