For more than 50 years, the world’s two largest nuclear superpowers — the U.S. and Russia — have agreed to rules limiting their nuclear arsenals. That arrangement ended on Thursday. Our national security correspondent David E. Sanger explains how we got here. Video by David E. Sanger, Coleman Lowndes, Nikolay Nikolov, Alexandra Ostasiewicz, Thomas Vollkommer, Laura Salaberry and Whitney Shefte/The New York Times #russia #trump #nuclear #treaty Read the story here: nyti.ms/3ZZJV1z Subscribe: bit.ly/U8Ys7n More from The New York Times Video: nytimes.com/video ---------- Whether it's reporting on conflicts abroad and political divisions at home, or covering the latest style trends and scientific developments, New York Times video journalists provide a revealing and unforgettable view of the world. It's all the news that's fit to watch.