As tensions grow in Eastern Europe, the role of NATO is crucial for our understanding of the reaction of the West to Russia’s troop build-up at the Ukrainian borders. NATO has undergone significant changes since it was founded more than 70 years ago when twelve countries came together to, as a British diplomat famously put it, “keep the Americans in, the Russians out, and the Germans down.” Today, the North Atlantic Treaty Organization has almost thirty members and its missions have changed significantly. In this episode of the HCA podcast, Anja Schüler and Seth Johnston take a look at these changes in NATO’s organization and strategy. Seth Johnston is assistant professor in the Walsh School of Foreign Service at Georgetown University. As a scholar-practitioner, he also has served in the Pentagon and the State Department as well as in many multinational overseas missions.