Russia is expanding its nuclear capabilities into neighboring Belarus, increasing the number of tactical arms at NATO’s Border. Moscow says deploying its arsenal in Belarus mirrors NATO’s nuclear-sharing agreements but what could this mean for global non-proliferation efforts? WSJ examines how these efforts threaten Europe and NATO. Chapters: 0:00 Russia-Belarus nuclear arms 0:32 History of nuclear arms in Belarus 1:13 Bringing nuclear arms back 2:23 Why Russia is sharing nuclear arms 3:24