On Friday, a nonproliferation pact that underpinned three decades of global security will collapse. In 1987, the United States and the Soviet Union agreed to the Intermediate-Range Nuclear Forces Treaty, which led to the removal of more than 2,600 U.S. and Soviet nuclear and conventional ballistic missiles - specifically, ground-based weapons systems with ranges between 500 and 5,500 kilometers (310 and 3,417 miles). That proximate distance, and the fact that they could hit their targets within 10 minutes, made such missiles the source of constant miscalculation fears during the Cold War era.