These words show that Einstein had envisaged a nuclear Armageddon, which will cause the left over population to return to the stone age. Consequently nuclear proliferation in the world has been deemed as a seedbed of incessant terror alongside a temptation for power and deterrence along the globe. Thus caused this issue to be at the forefront of the international security agenda since 1945. The idea of a nuclear bomb amid a precarious world prone to wars was marked as a watershed in the history of warfare. Us became the first nuclear power and bombed Hiroshima and Nagasaki in 1945, killing 129000 people instantly. It was one of the most devastating attacks in the history of mankind with its effects lasting for generations.
After this incident, Soviet Union intensified its nuclear program and became nuclear power in 1949. By 1962, the "Nuclear Club" expanded to include all the permanent five members of United Nations Security Council.
While these states were preoccupied with the arms race, an alarming agitation rose among the civilians, which resulted in Anti-Nuclear Weapons movements. This escalating pressure became the genesis of Nuclear Non-Proliferation treaty in 1968, which attempts to limit the spread of nuclear arms to other states while recognizing P5 as Nuclear Weapons states. This treaty was asserted to be prejudiced as it controls horizontal proliferation without barring vertical proliferation. For this reason India, Pakistan and Israel did not sign it.
After the Sino-Indian war, India intensified its Nuclear program as a deterrence against China and tested its first nuclear device in 1974. Pakistan also carried out Nuclear tests in 1998, a fortnight after India carried out nuclear tests for the second time. The last state to enter the nuclear arsenal was North Korea in 2006. While Israel is also believed to possess nukes clandestinely since it neither accepts nor rejects being a nuclear power.