CLM Insights Interview with Fiona S. Cunningham

Fiona S. Cunningham. Under the Nuclear Shadow: China’s Information-Age Weapons in International Security (Princeton Studies in International History and Politics). Princeton University Press, January 2025. 400 pages. ISBN-10: ‎0691261032; ISBN-13: ‎978-0691261034

Fiona S. Cunningham CLM Issue 87 March 2026.pdf

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Insights Interview

In your book you advance a novel theory of “strategic substitution” that explains the decisions made by successive Chinese leaders in the post-Cold War era to modernize the military. Can you briefly summarize its main points? What are the advantages and limits of “strategic substitution”?

Strategic substitution captures China’s novel approach to generating coercive leverage against a nuclear-armed adversary in a future war. That approach relies on threats to escalate a conflict using information-age weapons—counterspace weapons, offensive cyber capabilities, and precision conventional missiles—but not nuclear first use. Rather, strategic substitution dares an adversary to use nuclear weapons first to respond to these non-nuclear attacks. Strategic substitution is a distinct way of coping with the limited war dilemma that nuclear-armed states face because they want to use their military capabilities to coerce their adversaries but do not want to trigger a nuclear catastrophe. Other nuclear states have relied on threats of nuclear first use or a decisive conventional victory to cope with this dilemma.

The theory of strategic substitution explains why China pursued each information-age weapon to realize this approach. The theory posits that a nuclear-armed state pursues information-age weapons after it experiences a crisis with an adversary that exposed a leverage deficit, and it follows a distinct set of priorities in its response. Leverage deficits create a sense of urgency for decision-makers to search for ways to plug gaps in their military capabilities and shore up their bargaining position in future crises. In the absence of a leverage deficit, they simply implement existing plans for military modernization.

China’s search for coercive leverage led it to pursue information-age weapons because it prioritized the speed and credibility of its steps to address its leverage deficits. Given such priorities, either adopting a nuclear first use posture or pouring all its resources into conventional military modernization that could eventually achieve decisive victories were unattractive options. The nuclear option was not credible and the conventional option was too slow.

The advantage of strategic substitution is that information-age weapons are less destructive than nuclear weapons, which makes threats to use them more credible. They are also quicker to develop than correcting an unfavorable conventional military balance, which can take decades in a best-case scenario.

The key limitation of strategic substitution is uncertainty about its effectiveness. The approach has never been tested in a serious crisis, unlike threats of nuclear first use and overwhelming conventional military capabilities, which are tried and tested even if they do not always succeed. It also does not degrade the adversary’s ability to respond by continuing to fight a conventional war or make nuclear threats.

What makes information-age capabilities appealing for Chinese leaders? What are the downsides of relying on such capabilities in exercising coercive leverage? Can you provide us a few recent examples?

In the late 1990s and early 2000s, information-age weapons offered Chinese leaders a way to sidestep the choice between abandoning their nuclear no-first-use policy and losing a conventional war over Taiwan if the United States intervened. They promised to threaten escalation, mostly because of their rapid and damaging effects across long ranges and their ability to cross important thresholds in limited wars. Information-age weapons made strategic substitution possible.

Scholars debate whether anti-satellite weapons, conventional precision strike missiles, and offensive cyber operations targeting critical infrastructure networks are escalatory, compared to conventional warfighting. Around 2000, however, People’s Liberation Army (PLA) authors breathlessly described the coercive impact these weapons could have on a technologically advanced, nuclear-armed adversary like the United States. They also declared that information deterrence (including cyberattacks) and space deterrence were much more credible than nuclear deterrence. Exposed to these views, China’s leaders decided to pursue information-age weapons at a time when the PLA had to be extremely selective about its investments.

The drawbacks of relying on information-age weapons for leverage have since become apparent. For example, around 2010 China’s leaders became aware of their own vulnerability to cyberattacks as the country’s digital ecosystem grew, which led them to worry more about blowback from PLA cyber activities. They took steps to calibrate their coercive cyber acts should a war occur, including stricter command and control arrangements for offensive cyber operations. More recently, China has analyzed the lackluster effects of Russian cyberattacks in Ukraine to determine whether offensive cyber capabilities are ill-suited for coercion. In the last five years or so, the United States government has adopted a Starlink-like concept for its future national security satellite constellations. This change will blunt the effects of the PLA’s anti-satellite weapons, which would have caused serious damage to a small number of exquisite satellites.

These drawbacks undermine the original appeal of strategic substitution, which promised to channel strategic conflict into the zone just below the nuclear threshold and gave China’s leaders the confidence that they could control it in that zone.

Under the Nuclear Shadow provides a valuable in-depth look at the process of national security decision-making in China in the context of adopting information-age weapons. Can you briefly share your key insights into this process?

I will highlight three key insights. First, the process of information-age weapons decision-making reveals how much the top leader versus the PLA is responsible for the weapons China acquires. My analysis shows that the top leader (in these cases, Jiang Zemin) did not have strong priors about which weapons China should acquire to address its leverage deficits. Jiang initiated the search for leverage and later approved the pursuit of the information-age weapon. The PLA was responsible for everything in between: identifying plausible substitutes and recommending which ones to pursue.

For example, Jiang Zemin’s reaction to the 1999 Belgrade Embassy bombing defined that event as a leverage deficit. He instructed the PLA to urgently search for more leverage. The PLA identified information-age weapons coercion as a solution after CMC Vice-Chairman Zhang Wannian transmitted Jiang’s instructions to the PLA and Chief of General Staff Fu Quanyou warned that the PLA had to work out how to “win from a position of inferiority.” PLA small groups studied the Kosovo war, investigated options, and developed recommendations that eventually reached Jiang.

Second, defense industry and military decision-makers clearly articulated the constraints on China’s search for leverage that led it to prioritize speed and credibility in that process. Leaders at this level were the main architects of strategic substitution. The options they took off the table ensured that China had to come up with a novel approach to cope with the limited war dilemma.

For example, Zhu Guangya, a nuclear scientist who oversaw China’s nuclear weapons design work and advised the General Armaments Department in the 1990s, expressed skepticism that threatening nuclear first use would work against a nuclear-armed opponent. Zhang Wannian warned of the PLA’s conventional military weaknesses and fiscal constraints. Both leaders impressed upon the PLA and defense industry that emulating foreign militaries without adapting their lessons to China’s situation was unacceptable.

Third, examining the decision-making process does not reveal everything that we need to fully understand China’s choices. I had to look beyond the decision-making process to uncover some important factors that influenced China’s selection of these information-age weapons. Examining China’s decision-making process alone would suggest that the PLA simply chose the best weapons available for pursuing coercive leverage once defense industry and military leaders had ruled out nuclear first use and decisive conventional victory. But I compare the PLA’s actual decisions with some plausible alternatives. This comparison revealed that both the availability of technology and the party’s ability to control weapons with strategic effects were implicit factors in the decision-making process.

For example, in January 1996, shortly after finalizing the 9^th Five-Year Plan period military building plan to invest heavily conventional missiles, CMC Vice-Chairman Liu Huaqing recognized the backwardness of the PLA’s bomber aircraft, which could have otherwise delivered conventional munitions in a similar manner.

How have more recent developments in Chinese military modernization, especially its rapid nuclear build-up and acquisition of more powerful conventional capabilities affected Beijing’s calculus regarding its coercive leverage, especially in a Taiwan scenario?

The future of strategic substitution as China’s answer to the limited war dilemma is uncertain. On the one hand, the United States is actively trying to undermine the leverage China gains from information-age weapons coercion. On the other hand, the nuclear and conventional options for coping with the limited war dilemma are more accessible to China today than in the past. That said, until recently strategic substitution has been a successful stopgap while China’s conventional military modernization progressed and its leaders were skeptical about the nuclear first use option.

Currently, U.S. analysts worry that a U.S.-China conventional war over Taiwan could end in a stalemate (or worse) because of China’s conventional military modernization. Achieving a stalemate is not, however, the same as having a clear capability to achieve a decisive conventional victory. That capability could dissuade the United States from intervening in the first place because both sides would know Washington would lose the war. China would need that standard of conventional forces if it were to replace strategic substitution. Even if a conventional conflict ended in a stalemate, then China would still need options to escalate to win.

If China cannot rely on its conventional forces to answer the limited war dilemma, might it replace strategic substitution with nuclear first use in the future? China’s information-age weapons would be transformed from substitutes to complements for nuclear first use in this scenario. If China lost confidence that its information-age weapons could provide the leverage it needs to deter the United States, it might reconsider the nuclear option. Alternatively, Xi Jinping and his advisers might believe that nuclear first-use threats would be credible against the United States, upending the leadership-level nuclear beliefs that shaped China’s choice of strategic substitution.

Although China has dramatically accelerated its nuclear modernization since 2019, my ongoing research has not revealed much evidence of China embracing nuclear first use or changing its views on the credibility of nuclear threats. Instead, the key factor explaining China’s accelerating nuclear modernization is domestic changes in terms of who influences nuclear strategy.

How do recent rapid advances in information-age weapons, such as drones and AI, influence Chinese approach to “strategic substitution”?

Not all military capabilities that can be described as information-age weapons are plausible substitutes for nuclear first use and decisive conventional victories. (In fact, I use the term as shorthand for offensive cyber operations, counterspace capabilities, and precision conventional missiles rather than all weapons that emerged during the information age and that depend on information networks.)

The theory of strategic substitution focuses on “some weapons [that] are particularly well suited to making threats of escalation because they create additional pathways for a limited conventional war to become a nuclear war” (page 26). It lays out three criteria for identifying such weapons. First, they threaten large-scale damaging effects on an adversary’s society, military, or allies that are difficult to defend against. Second, their use crosses important thresholds in limited wars. Third, they share technology with nuclear arsenals such that their use creates inadvertent nuclear escalation risks.

AI does not satisfy these criteria because it is a general-purpose technology, but it could prompt a shift in China’s answer to the limited war dilemma. It is likely to affect the information-age weapons China uses to implement strategic substitution as well as its conventional and nuclear capabilities. If China can reap significant advantages over the United States on the conventional battlefield through the military applications of AI, then China might shift its answer to the limited war dilemma to a decisive conventional victory.

Among China’s information-age weapons, armed unmanned aerial vehicles (UAVs) are most similar to conventional missiles, but the PLA has thus far focused more on warfighting applications of UAVs. There are two possible reasons for this outcome.

First, until recently, armed UAVs have arguably fallen short of the criteria for a plausible substitute. Armed UAVs have shorter ranges, are less efficient in delivering firepower, and are more susceptible to adversary countermeasures than conventional missiles. Unlike China’s dual-use missiles, its unmanned systems are not (yet) used to deliver nuclear weapons. In recent years, however, the Russia-Ukraine war demonstrated applications of unmanned systems that could generate coercive leverage. For example, Ukraine attacked the Russian nuclear bomber fleet using dozens of small, cheap drones in Operation Spider’s Web. Autonomous guidance in the terminal phases of drone operations and swarms of cheap unmanned systems also increase the firepower efficiency and the difficulty of defending against unmanned systems. These recent changes make unmanned systems a more plausible substitute today.

Second, the theory of strategic substitution suggests that unless China faces a leverage deficit, it is more likely to use unmanned systems to enhance its conventional military operations than for coercive leverage. The most plausible reason for China to experience a leverage deficit since the beginning of the Ukraine war was Nancy Pelosi’s visit to Taiwan in August 2022. But it is difficult to confirm with available sources whether Chinese leaders viewed the event as such and whether they searched for leverage thereafter. I plan to keep a close eye on these trends to understand the future of strategic substitution in China.