Many theories exist on the 'why' and 'how' of nuclear proliferation such as 'classical realism' and 'neo-realism' but what is generally accepted is that the locus is external in nature. As per Fry, "If a state bids for hegemony, other states willform an alliance to contain and deter the expansion-revisionist states" (Fry 3). This is based on the assumption that states seek to, "maximize their power in order to survive in a competitive international system," (Ogilvie-White 44). Hence, nations who see a perceived threat to their national interests or in extreme cases to their very existence (as in the caser of Israel) seek to acquire a nuclear deterrent since "security represents the intimate challenge to a states survival (Ogilvie-White, 45).
This theoretical debate is best exemplified by the arguments propounded by Scott D. Sagan and Kenneth N. Waltz in their book 'The Spread of Nuclear Weapons, A Debate' (New York: WW Norton and Company, 1995). This scholarly debate has two basic schools, one that views states as unitary, rational entities and the other which feels that proliferation occurs as an outcome of organizational interests. Both views have their merits and limitations as will be expanded upon. However, it is quite apparent that given existing geo-political realities, more and more states will seek to acquire nuclear weapon capabilities as a safeguard against nuclear blackmail.
The first school of thought, led by Kenneth Waltz are the proliferation 'optimists' in that they feel that nuclear proliferation is not necessarily a negative outcome, and that contrary to popular belief, it may even have contributed to world peace. According to this theory of 'rational deterrence', "once more than one state has acquired a second-strike capability, war between the nuclear armed states is unlikely to occur, due to the fact that mutual destruction is almost assured" (Waltz 1990, 734). Waltz argues that near parity in nuclear weapon capability leads to a reduced probability of armed conflict on account of the prohibitive costs of waging war; unacceptable levels of mutual destruction; and lesser chances of miscalculation by the political leadership, since the ramifications such miscalculation would be catastrophic. This theory certainly gains some credibility when one considers that there has been no all-out war between two nuclear powers.
However, Waltz qualifies this optimism by laying down certain pre-conditions that have to exist for stable deterrence. These are firstly, that "there should be no preventive war while a state is developing its nuclear capability; secondly, "both states must develop a sufficient second-strike force to retaliate if attacked first; and thirdly, "the nuclear arsenals must not be prone to unauthorized or accidental use" (Sagan and Waltz, 51). This position seems quite reasonable since nuclear wars are more likely in conditions of asymmetry, even though the asymmetry might be in terms of conventional military capability. It also reinforces the rationale of states seeking to acquire nuclear weapons capability in order to maintain the balance of power through nuclear deterrence. This would be particularly true of states which see themselves surrounded by inimical neighbors, as in the case of