The Role of Nuclear Weapons in the 21st Century

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The Role of Nuclear Weapons in the 21st Century

April 13, 2005 5 min read
Baker Spring
Baker Spring
Former Kirby Research Fellow in National Security Policy
Baker is a former Kirby Research Fellow in National Security Policy

There has been considerable debate over nuclear weapons research programs-such as the Modern Pit facility, Robust Nuclear Earth Penetrator, Enhanced Test Readiness, and Advanced Concepts-in the wake of Congress's decision to cut their funding. Although it is unclear whether funding will be restored, some members of Congress are clearly unwilling or unable to understand the evolving role of nuclear weapons in modern national security. At a recent Heritage Foundation event, a panel of experts examined the role of nuclear weapons in the 21st century and their requirements, such as delivery systems, warhead designs, and technology.


The Changed Role of Nuclear Weapons

The role of nuclear weapons today is different than it was during the Cold War, but the lessons of the Cold War are still instructive. How do we judge if nuclear weapons were successful in their Cold War role? What might be the new standards in today's world?


During the Cold War, the role of nuclear weapons was shaped by the nature of the opponent-the Soviet Union, a fellow nuclear superpower-and reliance on the "balance of terror." Furthermore, holding societal, urban, and industrial targets-and not primarily military targets-at risk was held to be stabilizing. This in turn dictated the numbers and types of nuclear weapons required. The ultimate mechanism of deterrence, which proved extremely effective and certain, was this "balance of terror."


In the post-Cold War world, Russia is no longer the enemy. Today's threats are regional powers armed with weapons of mass destruction (WMD) and long-range delivery mechanisms. Lesser military powers may now be able to hold at risk U.S. military and civilian targets. Deterrence is an uncertain tool in this environment, and capabilities that were formerly stabilizing may now exert destabilizing effects.


Several questions must be considered in this new environment:

  • Is there a continued deterrence role for nuclear weapons?
  • What does the changing role of deterrence mean in terms of numbers and types of weapons?
  • How can the U.S. best respond to any dramatic changes in threats?

Even in the post-Cold War environment, deterrence remains important. The Cold War arsenal must be adjusted, in numbers and types of weapons, to provide deterrence in a new and dynamic situation. And the U.S. needs to be able, more than ever before, to respond to dramatic changes.


A New Set of Requirements

The time is right to look with renewed energy at what is being done in the nuclear weapons field. With increasing proliferation worldwide, four main concepts described in the 2002 Nuclear Posture Review (NPR) are important:

  • Assure: Friends and allies not confident in U.S. deterrence may arm themselves with their own capabilities. It is necessary to assure friends and allies alike of continued U.S. capability and that deterrence is not a bluff.
  • Dissuade: Dissuasion involves staying ahead of the curve on modernization of forces and force posture and using that position of strength to ensure that no country or other power wants to compete.
  • Deter: Deterrence is still an essential concept in the post-Cold War environment, but today's circumstances, such as increasing proliferation, mean that weapons must be more flexible. Stability, credibility, and the correct mix of capabilities are all more critical than the sheer number of weapons.
  • Defeat: In order to defeat an adversary, the right capabilities (for example, high accuracy, low yield, and uniquely tailored weapons) must be on hand when required. It is important to not foreclose any options when the strategic environment is as dynamic as today's.

The Nuclear Posture Review prescribed a flexible nuclear weapons policy. This is necessary in today's environment of multiple players with different strengths, which has replaced the two-player model of the Cold War. However, policymakers should remember that nuclear modernization is not only about weapons, but also about delivery systems. This necessary infrastructure and the programs that support it are suffering from neglect. Furthermore, new military requirements should be developed to address this changed environment and to ensure a modern strategic force capable of dealing with different kinds of missions:

  • Leadership and command and control targets, which may operate from heavily fortified underground locations;
  • Hostile nuclear coalitions, which may include rogue states, failed or failing states, powerful terrorist groups with potential to take over weak states, and terrorist groups based in sanctuary states;
  • New nuclear-armed allies, which may or may not have full confidence in the United States' deterrent ability; and
  • Electromagnetic pulse weapons (EMP), an effective deterrent that adversaries may be able to wield.

The United States must prepare its nuclear capabilities for all of these possibilities, while also establishing the correct offensive-defensive mix and maintaining a robust defensive posture.


The overarching question remains: What nuclear posture fits with our capabilities in a relatively seamless and integrated manner? The basic policy is in place, but it remains to be seen whether the programs can catch up with the policy.



The U.S. nuclear stockpile it little different from that designed to fight the Soviet Union and is nearly useless against today's threats. The U.S. can undertake several steps to modernize its nuclear capabilities:

  • Adopt a dual strategy of nuclear deterrence toward belligerent states and proliferation prevention among law-abiding states.
  • Terminate the test moratorium. Not only does testing benefit research into new capabilities, but it also maintains a safe, reliable, and effective stockpile.
  • Restore funding to research and develop new nuclear weapons appropriate in today's environment and re-establish an effective nuclear deterrent.
  • Focus global anti-proliferation efforts on the proliferation problem and not on nuclear disarmament.

Research from The Heritage Foundation supports many of these points. For more information, see Heritage Foundation WebMemo No. 618, Congress is Wrong to Defund Strategic Programs.


Baker Spring is F.M. Kirby Research Fellow in National Security Policy in the Kathryn and Shelby Cullom Davis Institute for International Studies at The Heritage Foundation. Kathy Gudgel, Research Assistant in Defense and National Security, contributed to this piece. This WebMemo is based on presentations given at "The Role of Nuclear Weapons in the 21st Century," a public event held at The Heritage Foundation on Monday, March 14, 2005. Panelist presentations are available at


Baker Spring
Baker Spring

Former Kirby Research Fellow in National Security Policy