The last Russia-US nuclear treaty is about to expire. What happens next?
Item 1 of 3 US President George Bush and Soviet President Mikhail Gorbachev exchange pens after signing the START treaty. July 31, 1991 REUTERS/Mal Langsdon DISCLAIMER: The image is presented in its original, uncropped, and untoned state. Due to the age and historical nature of the image, we recommend verifying all associated metadata, which was…