How many existing basic design types are there of the weapons the United States and the Soviet Union had an arms race over?
Nuclear weapon design Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types. In many existing designs, the explosive energy of deployed devices is derived primarily from nuclear fission, not fusion. (This includes fission of any U-238 tamper or casing due to fusion produced neutrons.)
Intermediate-Range Nuclear Forces Treaty The Intermediate-Range Nuclear Forces Treaty (INF Treaty) is the abbreviated name of the Treaty Between the United States of America and the Union of Soviet Socialist Republics on the Elimination of Their Intermediate-Range and Shorter-Range Missiles, a 1987 agreement between the United States and the Soviet Union (and later its successor states, in particular the Russian Federation). Signed in Washington, D.C. by President Ronald Reagan and Soviet leader Mikhail Gorbachev on 8 December 1987, the treaty was ratified by the United States Senate on 27 May 1988 and came into force on 1 June 1988.