The increase in the number of nuclear powers will affect nuclear strategy especially with regard to international stability and the possibility of the outbreak of war. The question that then arises is how the strategic doctrines of small and secondary powers will differ from those of the great powers. The multiplication of nuclear powers, or the expansion of the 'nuclear club', has been given several labels: the proliferation, spread, dissemination, dispersion, or diffusion of nuclear weapons, or, the Nth Country Problem. A war between two states may be caused by a third party, a 'catalytic' agent. People normally shrink from contemplating the horrors of war, a phenomenon which is termed "psychological closure" or "denial". The appearance of the world and the nature of war will be affected not only by the development and dispersion of nuclear weapons, but also by the development of other types of weapons.