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The Effect of Deep U.S. Nuclear Force Reductions on Nuclear Proliferation and Deterrence

Recently, President Barack Obama urged the international community to work towards nuclear disarmament. The United States, he declared, would take the lead to a nuclear-free world by reducing its nuclear arsenal. Such a move would signal a stronger U.S. commitment to the non-proliferation regime, which calls for the nuclear powers to eventually relinquish their arsenals. His initiative also echoes calls by distinguished policy-makers, including former Secretaries of State Henry Kissinger and George Schultz, urging the United States to relinquish its nuclear weapons. When presenting these bold objectives, the President underscored the need for "persistence and patience" to reach worldwide nuclear abolition.

Although the President has laid out a clear objective for this country, how other countries might react in terms of their nuclear weapons policy remains less clear. Indeed, the effect of deep U.S. reductions on nuclear proliferation and deterrence will likely determine whether or not the President's expressed aspiration for worldwide abolition is possible. This project examines the effect of deep reductions in the U.S. nuclear arsenal on the behavior of allies and potential adversaries. To help NNSA understand the changing nuclear proliferation landscape, the project will address the following questions: 

  • How might deep nuclear stockpile reductions affect the future of nuclear weapons proliferation?
  • How will moving towards abolition affect the ability of the United States to extend deterrence to allies, especially to those allies without nuclear weapons but with the potential to acquire an arsenal of their own?
  • How do countries other than the United States view the utility of nuclear weapons? As the United States reduces its arsenal, will other countries view nuclear weapons as more or less attractive? What can the United States do to reduce the perceived utility of nuclear weapons?

The relationship between deep reductions in nuclear arsenals and nuclear proliferation is not well understood. This subtask will provide a framework to understand how the U.S. move towards nuclear abolition might influence the proliferation behavior of allies and potential adversaries. The effort's initial activities will examine the potential reactions of U.S. allies to deep reductions. In Parts 1 and 2, the project will assess the ability of the United States to extended deterrence to allies and the conditions under which potential allies would perceive these efforts as credible. If allies respond to U.S. reduction by acquiring nuclear weapons, then they could become a significant obstacle on the road to worldwide abolition. The project will then assess the reaction of states outside of the American nuclear umbrella to deep reductions, including the reaction of potential U.S. adversaries. Part 3 examines international views on the utility of nuclear weapons and discusses various U.S. options to reduce the perceived utility of nuclear weapons.

This effort should interest the Department of Energy's National Nuclear Security Administration in their non-proliferation mission for four reasons. First, the project aims to provide a set of indicators about the nuclear-proliferation behavior of allies and potential adversaries in a world where the U.S. moves towards a sharply lower nuclear arsenal than the one deployed today. Second, the project will examine how deep reductions affect the ability of the U.S. to extended deterrence. Third, the project will help NNSA understand how countries outside the U.S. nuclear umbrella perceive the utility of nuclear weapons, the central driver of nuclear proliferation. Finally, the project will suggest some steps the United States might take to reduce the perceived utility of nuclear weapons as way to curb nuclear proliferation.

Part 1: Can the U.S. Extended Deterrence to Allies after Deep Reductions?

Alliance commitments remain one rationale for U.S. nuclear weapons. This task asks whether or not old concepts of deterrence are still relevant to U.S. national security policy. During the Cold War, U.S. policy-makers believed they needed to threaten the first-use of nuclear weapons to deter a Soviet invasion of NATO due to perceived conventional weakness in Central Europe. What remains unclear about today is whether the United States must make nuclear threats to deter conventional or nuclear attacks on allies. In particular, we will examine whether or not credible U.S. extended-deterrence commitments require nuclear threats in a world with multiple nuclear powers, a realistic possibility that prudent planners must consider. This task will require the project to review the literature on the future of warfare as well as debates about U.S. grand strategy. We will supplement our research by interviewing policy-makers and scholars in the United States.

Part 2: How Will Allies Perceive Deep Reductions in the U.S. Nuclear Arsenal?

This task will explore the possible effects of steep reduction in the U.S. nuclear arsenal on its friends and allies. To accomplish this task, we will review the literature on the causes of nuclear proliferation, assess the ability of the U.S. to credibly extended deterrence without nuclear weapons through an analysis of the required capabilities to protect American allies, and interview relevant policy-makers in allied countries. To date, there are few comparative assessments about how U.S. allies think about the desirability of the American nuclear umbrella and what kind of protection it actually buys them.

Part 3: What are International Perceptions about the Utility of Nuclear Weapons?

In this task, the project will explore the perceived utility of nuclear weapons by states outside the U.S. nuclear umbrella. The project will examine how non-U.S. allies view the advantages and disadvantages of nuclear weapons. This task will employ two methods of data collection. First, we will examine the strategic writings of current or aspiring nuclear powers to discern different rationales for nuclear acquisition. Second, we will interview relevant policy-makers in different countries to determine the perceived strategic value of nuclear weapons, especially how they perceive these weapons as instruments of deterrence. To date, there is little work comparing international views about the requirements of deterrence. We will also try to discern how much the desire for international prestige and domestic political consideration determine the value of nuclear weapons. Finally, this task will examine potential U.S. strategies to reduce the utility of nuclear weapons. We will assess the costs and the benefits of existing proposals about how the United States could immediately begin to lower the perceived value of nuclear weapons, including reductions in its own arsenal and the extension of security guarantees.


  1. J.J. Castillo, "Deliberate Escalation: Deterrence Strategies of Regional Nuclear Powers," The Annual Meeting of the American Political Science Association, Washington, DC, September 2-5, 2010.
  2. J.J. Castillo and C. Layne, "Strategic Challenges Facing Regional Nuclear Weapon Powers: Initial Arguments from the Case of Pakistan," Proceedings of the 2010 Annual Meeting of the International Studies Association, New Orleans, LA, March 2010.


Russia and U.S. Sign Nuclear Arms Reduction Pact
Russia and U.S. Sign Nuclear Arms Reduction Pact

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