has become axiomatic to note that the world has changed with the demise of the Soviet Union. In the area of nuclear weapons, the shift has been particularly apparent. Although it is obvious that the world has been transformed, it is less apparent how the world has changed, that is, how the observed nuclear changes relate to the end of the cold war. This essay argues that an understanding of nuclear policy-making requires the inclusion of a less tangible factor- a psychological factor- which we will call the "nuclear conception". Such conceptions underlie most nuclear policies and have likely always played a major role in nuclear strategies. The key conclusion of this essay is that the changes currently apparent in the realm of nuclear policy are in part due to the fact that nuclear conceptions are in the process of fundamental change and these changes will have broader implications for US nuclear strategy. This change in conception, while largely sparked by US-Soviet rapprochement, is deeper than the simple suspension of superpower ideological competition.