During Cold War most of the public attention was given on the political struggles between the U.S. and the former Soviet Union. Both were not only agents of an aggressive expansion conflict in the territorial-political space but also a vehemently fought contestation over economical and moral superiority. Both represented from their own point of view the “good”, feeling threatened by an opposing “bad” other side.
Regarding the very expensive issue of the development of a national nuclear program there is a certain need for such a construction of an opposing other part. Otherwise there would be no (economic) justification of the enormous costs in developing and maintaining weapons of mass destruction such as nuclear weaponry. In this sense, every nuclear power constructed its own rights and duties for its nuclear arsenal.
The United States started the nuclear race in fear of a German atomic bomb during Second World War (even full scale pacifist Albert Einstein felt committed to act against this threat and wrote the famous Einstein-Szilard letter also known as Einstein-Roosevelt letter in which he pointed to the new technology).
Confronted with the powerful effect of U.S. nuclear weapons the Soviet Union was kind of obliged to develop an own nuclear program with its first nuclear test in August 1949. The United Kingdom and France both felt the fading influence on global politics after the retreat from their colonies and the heavy loss during World War II, so the UK helped the U.S. to develop the bomb (for their own benefit of a first nuclear test in 1952 of course as well) and France took enormous efforts to build up a program themself, rearranging its whole military juggernaut with a big focus on nuclear powers as a deterrent after a first test in Februray 1960.
After the military and political implications by nuclear weapons became acceptable in polite society, the upcoming moment for People’s Republic of China in nuclear devopment was based on the Taiwan Strait Crisis in 1954-55. In the aftermath of the conflict some scholars have argued that Red China had retreated because it was aware of a possible nuclear conflict between the influence pushing U.S. and following Soviet retaliation options. Mao Zedong realised how helpful only some nuclear bombs might be and set up a Chinese nuclear program with its first atomic test in October 1964.
In the aftermath of a border conflict with China and the including loss of territory in Octobre 1962 provided the Indian government with a justification for atomic weapon possession as a deterrent: Code named “Smiling Buddha” was the first Indian nuclear device test in 1974, which was called a “peaceful nuclear explosion“.
Challenged by the neighboring development of nuclear weapons and the “Smiling Buddha” detonation as a first nuclear device test outside the permanent five members of th United Nations Security Council paved the way for Pakistani nuclear endavour. In May 1998, a few weeks after India’s second nuclear test, Pakistan detonated five nuclear devices and became able to sit on same height as its neighbours.
There are no futher proves but it is widely believed that Israel possesses nuclear weapons. Seen in the light of its secluded position in Middle East, one could consider the temptations of a deterring nuclear weaponry.
Just recently, another nation felt threatened enough to join the nuclear table: After resigning from the Nuclear Non-Proliferation Treaty in 2003, North Korea announced in October 2006 it ha2d successfully counducted its first nuclear test in an underground explosion, followed by two more tests in May 2009 and February 2013. The obscurity and isolation of the communist regime makes it difficult to estimate political ambitions but it is clear that with the nuclear capacity it gave itself a certain protection.
The build up of a nuclear arsenal of one state has political implications and direct effects on concurring states in the way it threatens the former political and military settings. The Soviet Union and the U.S. nuclear contest had its climax in 1986 with together more than 64000 nuclear devices. Since the end of Cold War, the amount of global stockpile is decreasing, mainly because of the ongoing deconstrution of these two massive nuclear arsenals. But one must not forget that the other nuclear agents are still bound in their own political struggles and still felling committed to build up a nuclear arsenal for so-called seld-defence. Not realising that with every device built, its opposing part feels threatend as well and tries to close the gap in the nuclear race. Certain things cannot be performed alone.