Changes

In 1961, Kennedy established an Arms Control and Disarmament Agency within the U.S. Department of State, and the new organization reopened talks with the Soviet Union. That year, however, neither side was ready to make major concessions. As long as it remained difficult to verify that the other side was not engaging in clandestine testing, there was little incentive to form an agreement.

====China nuclear program and the Cuban Missile Crisis convinced US, USSR, and Great Britain to restart talks====

Over the course of the next year, however, the situation changed dramatically for a number of reasons. Concerns about nuclear proliferation increased interest in the testing ban, as France exploded its first weapon in 1960 and the People’s Republic of China appeared close to successfully building its own atom bomb. In 1961, the Soviet Union also tested Tsar Bomba, the largest nuclear test in history. The Tsar Bomba test had a blast yield of 58 Megatons TNT and represented a significant escalation of the arms race.