A Russian intercontinental ballistic missile is moved during military training in the mid-1990s near Irkutsk, Siberia, Russia. Arms control has been at the center of a decades-long discussion between Russia and the U.S.
A U.S. Navy senior chief petty officer stands watch ahead of a ceremony inaugurating the U.S. anti-missile station Aegis Ashore Romania at Deveselu, Romania, in 2016. The station is part of NATO's anti-missile shield for Europe.
Daniel Mihailescu/AFP/Getty Images