September 02, 2020

Toward a More Proliferated World?

The Geopolitical Forces that Will Shape the Spread of Nuclear Weapons

Executive Summary

The United States and the international community have been relatively successful at preventing the spread of nuclear weapons, but there are new reasons to question whether this track record will last into the future.

Working with partners, the United States has steadily built a framework of disincentives and barriers to prevent proliferation. These include: 1) international treaties and agreements that have erected legal, political, and normative barriers to the bomb; 2) U.S. security commitments to allies that dampen their own perceived need for nuclear weapons; and, 3) a set of tough penalties (e.g., sanctions) for those who get caught trying to build the bomb. In other words, the barriers to entry to the nuclear club are high, and those countries that want the ultimate weapon need to be willing to accept significant risks. This helps explain why, although many countries have explored or pursued nuclear weapons, only nine states have them today.

But several trends are eroding the foundation on which this formidable set of barriers rests. These trends are rooted in, and being shaped by, changes to the nature and structure of the international system: namely, the decline of U.S. influence and its gradual withdrawal from the international order that it helped create and lead for more than 70 years, and the concurrent rise of a more competitive security environment, particularly among great powers. These trends (detailed below) will have three broad implications for proliferation and U.S. policy. First, they stand to increase pressures on countries to seek nuclear weapons or related capabilities as a hedge. Second, they will almost certainly challenge the U.S. ability to effectively wield the traditional “carrots and sticks” of nonproliferation and counterproliferation policy and dilute the effectiveness of those tools. Finally, they could increasingly pit U.S. nonproliferation goals against other policy objectives, forcing harder tradeoffs.

Seven Trends that Will Shape the Future of Proliferation

1. Nuclear threats are increasing, and regional security environments are becoming more tense, thereby creating proliferation pressures.

Countries that pose a threat to the United States and its allies—including Russia, China, and North Korea—are modernizing and expanding their nuclear arsenals and behaving more aggressively. Even if Iran refrains from producing nuclear weapons, its latent capacity to do so and malign activities in the region will require U.S. attention. These developments threaten the United States and its allies directly and are placing additional stresses on the U.S. alliance system. Although not determinative of proliferation, deteriorating security environments and nuclear threats can act as primers for countries to reassess their own nuclear needs.

2. U.S. allies and partners are losing trust and confidence in the United States—including Washington’s willingness to uphold its security commitments—increasing the risk that they will seek nuclear weapons or weapons-relevant capabilities. Relatedly, the United States could find itself hard-pressed to adequately assure allies to address any proliferation ambitions that do emerge.

Since the early years of the Cold War, U.S. commitments to provide for the security and defense of other countries have played an important role in keeping proliferation at bay. And when confronted with an ally considering nuclear weapons, the United States has threatened to reduce these security commitments—or alternatively, to enhance them—to prevent an ally from proliferating. But fundamental trust in the United States appears to be on the decline, increasing the risk of proliferation by U.S. allies and partners.

3. The rise of authoritarian leaders is increasing the chances of nuclear proliferation.

There is a correlation between certain types and characteristics of autocratic rulers and their propensity to go after the bomb. These leaders face fewer domestic checks on nuclear weapons ambitions and might be more willing to try to weather international pressure. The rise of authoritarianism as a global phenomenon—particularly among some U.S. allies and partners—is therefore worrying from a proliferation perspective.

4. Prospects are dim for arms control measures that can further reduce U.S. and Russian nuclear weapons or cap growing global nuclear weapons arsenals. As a result, the bargain at the heart of the Nuclear Non-proliferation Treaty (NPT)—whereby nonnuclear weapon states refrain from acquiring nuclear weapons and in exchange nuclear-armed states work toward disarmament—is likely to come under further strain.

Cooperation between the United States and Russia on nuclear issues is nearly nonexistent, and arms control agreements are an endangered species. An arms race—or even the perception of one—will make it harder for Washington and Moscow to defend the notion that they are living up to their NPT commitment. The expansion of other countries’ nuclear arsenals does not bode well for treaties and agreements not yet in force (e.g., the Comprehensive Nuclear Test Ban Treaty and the prospective Fissile Material Cut-Off Treaty), and whose implementation many nonnuclear weapon states see as vital for the health of the nonproliferation regime and the NPT.

5. The ability of the United States to use civil nuclear energy sales and assistance to advance nonproliferation objectives is declining.

Washington has long leveraged the ability of the United States to export nuclear reactors, fuel, and technology as a means to promote nonproliferation controls (such as constraints on enrichment and reprocessing activities by countries receiving U.S. nuclear technology and the adoption of the Additional Protocol (AP), which enhances the authorities of international inspectors) and as a stick to convince countries to end nuclear weapons programs. But the United States is no longer the major player in the nuclear energy market. The increasing ability of China, Russia, and others to provide nuclear assistance on more competitive terms—and with fewer nonproliferation strings attached—is eroding the U.S. ability to write the rules of the game. If the United States has fewer nuclear energy clients, it is less able to monitor and shape the nuclear trajectory of key countries, including if necessary threatening to cut off its energy partnership to curb proliferation behavior.

6. The effectiveness of sanctions as a nonproliferation tool will likely diminish as countries develop ways to reduce their impact and U.S. financial dominance erodes over the long term. In addition, the risks and costs of sanctions use for the United States will increase as future sanctions targets will increasingly have the ability to retaliate.

U.S. overuse of economic sanctions is prompting a backlash. Countries and actors are developing workarounds and seeking ways to shield themselves from—and respond to—economic penalties imposed by Washington. This will make it harder for the United States to dissuade countries from engaging in sensitive activities related to nuclear weapons or their means of deliver, and make it harder to convince third parties (such as allies) to follow the U.S. policy line. It will also diminish the effectiveness of U.S. counterproliferation measures that seek to block countries’ ability to fund illicit weapons programs or purchase technologies abroad.

7. The more competitive relationship between the United States and Russia, and the United States and China will likely impede cooperation on nonproliferation and complicate U.S. implementation of nonproliferation policy.

A new era of deepened mistrust, competition, and differing objectives between Washington and Moscow and Beijing is already hampering cooperation on arms control. That discord is beginning to spill over into coordination on nonproliferation. Additionally, a focus on strategic competition as the top policy priority could, in some cases, be at odds with nonproliferation objectives and lead to those objectives taking a back seat. This could occur because the United States is loath to put pressure on a proliferating ally for fear that doing so would jeopardize cooperation against a shared adversary. It could also occur if, in seeking to bolster allied conventional military capabilities and enhance burden sharing, the United States provides or allows capabilities that improve a country’s ability to build nuclear weapons and/or the means to deliver them.

Policy Recommendations

U.S. policy must adapt unless Washington wants to be faced with a more proliferated world in the future. Nevertheless, the structural and systemic changes that are driving many of these trends mean that it will be difficult to arrest or reverse them. The best and most durable solutions are also ones that, because of the very nature of these trends, would be extremely challenging to implement over any sustained time frame. Thus, to be effective, sustainable, and realistic, U.S. policy needs to work with—rather than against—these trends. With this in mind, the United States should endeavor to:

Pursue nuclear deals with Iran and North Korea in a way that limits the risk of follow-on nuclear proliferation and broadens the application of enhanced nuclear monitoring and verification practices.

  • Build on the Iran nuclear deal (known as the Joint Comprehensive Plan of Action, or JCPOA) by working to regionalize nuclear limits and transparency measures.
  • Establish a forum to discuss regional issues in the Middle East, including missile and conventional capabilities, and work to develop confidence-building measures.
  • Think through where “denuclearization” fits in an arms control approach with North Korea.

Repair the trust deficit with allies, adapt alliances to be more resilient to the stressors of the geopolitical environment, and update assurance concepts to new threats.

  • Make it a top priority to signal U.S. commitment to allies and their security and end unnecessary sources of friction.
  • Hold off on big changes to nuclear policy and posture at the outset of a new Democratic administration.
  • Carry out a strategic review of how to update allied assurance to meet today’s threat environment.

Maintain a flexible and pragmatic approach—and acknowledge inherent limitations—to using U.S. civil nuclear cooperation for nonproliferation purposes.

  • Do not go for gold: Be flexible on approaches to so-called 123 agreements (the legal frameworks that underpin U.S. civil nuclear cooperation with other countries and govern recipients’ uses of the technology).
  • Establish a bipartisan commission to investigate what it would require for the United States to become a competitive player in the global nuclear energy market.
  • Enable U.S. allies in the nuclear energy market.

Assess, test, and strengthen the U.S. coercive toolkit as it applies to future proliferation threats, and identify and mitigate associated vulnerabilities.

  • Conduct a comprehensive review of U.S. sources of leverage and vulnerabilities against potential proliferators, their enablers, and key players with a stake in the outcome of proliferation scenarios.
  • Carry out a series of tabletop exercises to better understand the benefits and limits of these coercive tools—and how proliferators might respond.
  • Pass new legislation that updates the triggers for U.S. action against proliferators and the consequences that the United States can impose.

Focus on, and invest in, improving early detection of proliferation.

  • Better connect U.S. government efforts to leverage open source information, big data, and other advanced technologies to proliferation detection and counterproliferation policy needs.
  • Increase the International Atomic Energy Agency’s (IAEA’s) budget and encourage further investment in modern monitoring technologies.

A Note on the Goals and Scope of This Study

This project—a collaborative effort between the Center for a New American Security and the Center for Strategic and International Studies—is a survey of the geopolitical forces that will shape the proliferation landscape and the U.S. ability to manage it over the next 10–20 years.

In this way, it is different from studies that focus only on specific countries or regions of proliferation concern. Both approaches have strengths and weaknesses. Assessing whether and when a specific country might go nuclear allows for detailed analysis of particular political and technical circumstances. But such studies are limited in their ability to identify or evaluate the broad array of trends that can potentially drive or restrain proliferation, and how those trends affect the U.S. nonproliferation toolkit. This study is an attempt to fill that gap. It does not explicitly try to predict the number of nuclear weapons states in the future, nor does it undertake a thorough assessment on the likelihood that any particular country will develop nuclear weapons (although it does evaluate three countries—South Korea, Saudi Arabia, and Turkey—against the trends identified in the report). Rather, it primarily aims to serve as a guide for policymakers and analysts regarding what they should be worried about when it comes to proliferation, why, and what can be done about it.

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  1. Jessica Weeks and Christopher Way, “Making It Personal: Regime Type and Nuclear Proliferation,” American Journal of Political Science, 58 no. 3 (July 2014), 705-719; Matthew Fuhrmann and Michael C. Horowitz, “When Leaders Matter: Rebel Experience and Nuclear Proliferation,” The Journal of Politics, 77 no. 1 (January 2015), 72-87,; and Jacques E.C. Hymans, The Psychology of Nuclear Proliferation: Identity, Emotions and Foreign Policy (Cambridge: Cambridge University Press, 2006).
  2. For an example of these contrasting approaches, see Kurt M. Campbell, “Reconsidering a Nuclear Future: Why Countries Might Cross over to the Other Side,” in The Nuclear Tipping Point: Why States Reconsider Their Nuclear Choices, eds. Kurt M. Campbell, Robert J. Einhorn, and Mitchell B. Reiss (Washington: Brookings Institution Press, 2004), 18-31; and Robert J. Einhorn, “Will the Abstainers Reconsider? Focusing on Individual Cases,” in The Nuclear Tipping Point, 32-42.


  • Eric Brewer

    Deputy Director of the Project on Nuclear Issues (PONI) and Senior Fellow, Center for Strategic and International Studies (CSIS)

    Eric Brewer is Deputy Director of the Project on Nuclear Issues (PONI) and a Senior Fellow at the Center for Strategic and International Studies (CSIS). He was perviously the ...

  • Ilan Goldenberg

    Former Senior Fellow and Director, Middle East Security Program

    Ilan Goldenberg is the former Senior Fellow and Director of the Middle East Security Program at the Center for a New American Security. He is a foreign policy and defense expe...

  • Joseph Rodgers

    Program Coordinator, Project on Nuclear Issues, Center for Strategic and International Studies (CSIS)

    Joseph Rodgers is a Program Coordinator with the Project on Nuclear Issues in the International Security Program at the Center for Strategic and International Studies (CSIS).P...

  • Maxwell Simon

    Program Coordinator and Research Assistant, Project on Nuclear Issues, Center for Strategic and International Studies (CSIS)

    Maxwell Simon is a Program Coordinator and Research Assistant with the Project on Nuclear Issues in the International Security Program at the Center for Strategic and Internat...

  • Kaleigh Thomas

    Former Associate Fellow, Middle East Security Program

    Kaleigh Thomas is a former Associate Fellow for the Middle East Security Program and 2020 recipient of the 1LT Andrew J. Bacevich Jr., USA Award at CNAS. She also serves as th...

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