This article examines the impact of external conditions on the choice to develop a nuclear weapons program. A comparison of external conditions which influenced the nuclear choice of Pakistan with those which have been accompanying the development of the Iranian nuclear program assists in identifying the typical external factors that push threshold states towards acquiring nuclear weapons. These factors include: threats to a regimes survival and attractively high status of the nuclear powers. This article also offers recommendations that can help lower the negative impact of these factors on the threshold states.