The world's first nuclear weapons explosion on July 16, 1945, in New Mexico, when the United States tested its first nuclear bomb. Not three weeks later, the world changed.

How did nuclear proliferation start?

During World War II, the United States and its allies were afraid that their enemies would develop nuclear weapons first, so in 1942 they started the Manhattan Project, a secret research effort led by the U.S. government to develop nuclear weapons. ... Those atomic bombs remain the only ones ever used in war.

What is the root cause of nuclear proliferation?

The authors speculate that this is due to one of two causes: “democracies are more vulnerable to nationalist pressure” (Jo & Gartzke 2007a, p. 179) or “partial democratic states use nuclear weapons proliferation as a diversion for domestic political reasons” (p.