NUCLEAR WEAPONS HAVE REVOLUTIONIZED practice of war in 20th century. Prior to invention of such weapons in 1945, states in conflict could weigh their chances of military success against an adversary based on expected costs and benefits of going to war. Since introduction of nuclear weapons, however, balance of this strategic calculus has changed considerably. Deterrence theorists argue that nuclear weapons now take risk out of this calculation--the incredible destructive capacity of these weapons imposes such a high price on both warring parties that it renders any military victory virtually meaningless. In his pioneering work The Absolute Weapon, Bernard Brodie expressed this sentiment: thus far chief purpose of our military establishment has been to win wars. From now on its chief purpose must be to avert them. It can have no other useful purpose.(1)This paper questions basic soundness of nuclear deterrence regime between India and Pakistan, and argues that possibility of deterrence failure in this context is significant. Given historical, geographic and psychological context of these rival states, nuclear weapons are more likely to create greater insecurity (than security) for states involved. This view stands in stark contrast to analysis by South Asian security experts, like University of Texas professor Sumit Ganguly, who argues that the presence of nuclear weapons [in region] has actually made things better, for now.(2) The central argument is that new nuclear states such as India and Pakistan are, inevitably, drawn towards nuclear war by their need to undertake lowlevel aggressive actions to maintain credibility of their nuclear forces. Such actions, however, are in sharp contrast to distant battles that were fought between US and Soviet Union during Cold War, and these actions have a significantly higher probability of triggering a catastrophic deterrence failure.Beginning with an examination of evolution of nuclear deterrence theory, this paper pays special attention to developments particularly important to India and Pakistan. It then proceeds with a case study of nuclear weapons issue in India and Pakistan, up to present day. Drawing on theoretical insights provided in first section, it will then critically analyze stability of current deterrence regime. Finally, it examines some of implications that these findings have for security studies, setting agenda for future research.DOES DETERRENCE WORK? THEORETICAL INSIGHTSDeterrence is fundamentally based on an expressed threat that exacts a cost greater than potential benefits of an adversary's unwanted action, leading an adversary to avoid that unwanted action.(3) It can be based on a threat of punishment, where a state threatens to destroy assets that are valuable to its adversary if its own assets are destroyed. These punitive threats usually focus on targets such as cities and their economic infrastructure, objects that states value but which are unrelated to military operations. Deterrence can also be based on a threat of denial, where a state takes action of convincing its adversaries that their unwanted actions, such as an invasion, will be stopped and they will not achieve their military or political objectives. Denial threats usually target counterforce targets such as military units and weapons of mass destruction, which prevent unwanted military action from occurring. Ultimately, successful deterrence requires that actors being deterred believe that costs of a potential action outweigh plausible gains.During Cold War, nuclear deterrence emerged as a crucial component of US strategy, as American strategists believed that nuclear deterrence was necessary to prevent Soviet domination of Western Europe.(4) The West came to rely on nuclear weapons to deter Russian military action that could not be stopped with conventional military forces which were considered prohibitively expensive. …