This was a name given to the relations between the u. s. & the soviet union in the second half of the 20th century which saw the buildup of nuclear arms.

Cold war

Explanation:

Cold War, the open yet confined competition that created after World War II between the United States and the Soviet Union and their separate partners. The Cold War was pursued on political, monetary, and promulgation fronts and had just constrained response to weapons

The primary purpose for cold war is american dread of communist attack.