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Integrated Deterrence

Rethinking the strategic approach to counter the PRC’s gray-zone operations


IN 2014, the world witnessed a seemingly new kind of warfare, conducted below the level of armed conflict, when Russia resorted to what came to be known as “hybrid warfare” to seize the Crimean Peninsula from Ukraine. However, similar methods had been employed two years earlier, when the People’s Republic of China (PRC) forcibly seized Scarborough Shoal from the Philippines and then undertook a multiyear campaign of territorial conquest by using the world’s largest oceangoing dredging fleet to create artificial features in the South China Sea, providing it with “blue sovereign soil” in the form of a chain of military bases built on reclaimed maritime sites. Having cemented those gains without meaningful opposition, communist China has demonstrated a greater willingness and readiness to resort to the use of lethal force to coerce its neighbors to acquiesce to its campaign of territorial expansion. It has done so through aggressive execution of territorial sovereignty operations, coercion operations carried out by law enforcement, paramilitary and military forces, and the use of elements of its “Unrestricted Warfare” and “Three Warfares” doctrines and strategies. Over the past two years, under Xi Jinping, the Chinese Communist Party (CCP) general secretary and Central Military Commission chairman, the PRC has increased the level of actual and threatened use of lethal military force along its entire southern and eastern peripheries, most significantly against the Indian, Japanese and Taiwan militaries.

The year 2014 also saw Russia employ hybrid warfare to split off eastern districts in Ukraine’s Luhansk and Donetsk regions, as part of the first phase of the Russo-Ukrainian War. More recently, Russia spent a year threateningly positioning military forces on its border with Ukraine to coerce concessions on Ukraine’s shift to the West. The posturing proved to be a prelude to starting a conventional military invasion of the sovereign nation in late February 2022. For the PRC and Russia, their demonstrated willingness to use force is part of a shared goal to intimidate the United States’ allies and partners. Their aggression is intended to cause allies and partners to lose faith in the U.S.’s capabilities and national will to abide by its mutual defense treaties and agreements. Such threats of force also aim to condition the U.S. and other nations to acquiesce to China’s aggression and coercion.

The PRC’s campaign of territorial conquest ultimately includes the self-governed island of Taiwan, while Russia’s goals started with Ukraine and quite possibly include other states that were formerly part of the Soviet Union or its Warsaw Pact client states. Through this amplified aggression, both nations seek deterrence and coercive effects that preserve their territorial gains and create opportunities to continue the offensive in the operational and information environments.

After nearly a decade of success by the PRC and Russia in employing military, paramilitary, law enforcement and commercial means short of armed conflict — known as gray-zone tactics — as well as their military coercion of their neighbors, it is time to rethink the strategic approach to such challenges and how they might be deterred more effectively. Conventional deterrence has steadily regained the level of prominence it held in military, government and academic circles during the Cold War with the Soviet Union. Over the past two years, the world has seen firsthand the complexity of a challenged deterrence caused by adversarial powers’ gray-zone exploitations that could put into question the effectiveness of U.S. conventional deterrence. Adversaries are using actions below the threshold of conflict to achieve strategic goals and potentially can conduct aggressive actions and consolidate gains before the U.S. and its allies can respond.

A Chinese coast guard vessel fires a water cannon as it confronts Philippine fishermen near Scarborough Shoal in the South China Sea. The People’s Republic of China forcibly seized the shoal from the Philippines. THE ASSOCIATED PRESS

To some observers, deterrence has been weakened by a real or perceived decrease in U.S. economic power, military capability and national will. As U.S. Sens. Jim Inhofe and Jack Reed warned in a May 2020 commentary for the website War on the Rocks: “Currently, in the Indo-Pacific, that foundation of deterrence is crumbling as an increasingly aggressive China continues its comprehensive military modernization.” Michele Flournoy, former U.S. undersecretary of defense for policy, echoed those concerns a month later, writing in Foreign Affairs magazine that because of the “uniquely dangerous mix of growing Chinese assertiveness and military strength and eroding U.S. deterrence,” the risk of war was “higher than it has been for decades.”


The PRC and Russia are achieving traditional military objectives during peacetime through gray-zone warfare. It is a Cold War-like struggle that can, and indeed has, included the use of military force. Both authoritarian regimes have demonstrated a ready willingness to use military force as a backstop to gray-zone actions and for coercion. This approach can be described as messaging through aggression — a heavy-handed style characterized by belligerence and arrogance that aims to cause the intended target to self-deter and self-censor their conduct for fear of further violence and coercion. The PRC and Russia seek to demonstrate a superiority of will in their readiness to resort to force to influence adversaries and relevant actors to accept their territorial claims and avoid confrontation.

The means of coercion can include covert intelligence operations, cyber operations, economic sanctions, election interference, employment of maritime militias, military aid to opponents, propaganda, punitive political measures, resource exploitation, support for domestic political opposition, and trade constriction, interdiction (embargos) or manipulation, among other forms.

The People’s Liberation Army (PLA) conducts relentless coercive intrusions into the air, land and sea space of the PRC’s neighbors to wear down opponents and create new “normal levels” for such provocations, while also improving conditions to achieve military surprise and closer launching points for more aggressive moves.

In the case of Taiwan, the PLA’s intrusions are designed to deter the government from formally declaring the island’s independence, while desensitizing and demoralizing Taiwan’s military and civilian population and causing fatigue and stress in its combat personnel and systems. The PRC’s saber rattling seeks to reduce the will of targeted nations to engage in kind, curtailing political action. Such demonstrations are meant to instill fear, doubt and worry to weaken Taiwan’s resolve. In 2021 and the first half of 2022, the frequency of PLA intrusions into Taiwan’s air defense identification zone and the number of aircraft per mission increased dramatically, with near-daily intrusions in 2021.

Adversaries’ gray-zone victories chip away at deterrence and steadily increase their confidence that they can achieve even greater stakes in conventional warfare as the U.S. deterrence architecture is viewed as brittle and ineffective. Unconvincing responses to gray-zone aggression invite future aggression, as Elliott Abrams, a former U.S. assistant secretary of state and deputy national security advisor, wrote in a March 2022 article for National Review magazine titled “The New Cold War.” 

A Taiwan Air Force F-16 fighter monitors a Chinese bomber as it flies near Taiwan. THE ASSOCIATED PRESS

Further, as military and policy analysts David Santoro and Brad Glosserman have noted, as gray-zone operations continue to mount and remain unchallenged, they can unnerve U.S. allies and contribute to a perception that deterrence is eroding. This is especially true when the operations cause or threaten the loss of life, such as the hand-to-hand fighting initiated by PLA troops along the Sino-Indian border in 2020 that left 63 dead and over 40 wounded, and the 2019 ramming and sinking of a Philippine fishing boat by a Chinese fishing vessel — suspected of being part of the PLA’s maritime militia — that left the Philippine crew of 22 stranded in the water before being rescued by a Vietnamese fishing boat.

How, then, can adversarial gray-zone operations and coercion be deterred?

“American civilian and military strategists traditionally think of deterrence in two forms: deterring conventional or nuclear war,” retired U.S. Army Lt. Gen. James Dubik wrote in a January 2022 article for the Association of the United States Army. However, there is a third form of deterrence, Dubik noted, which is “deterring our adversaries from achieving their strategic goals below the threshold of conventional war.”

A 2019 report, “Revisiting Deterrence in an Era of Strategic Competition,” recognized the need to integrate this third form of deterrence. Santoro, Brendan Thomas-Noone and Ashley Townshend wrote the report for the United States Studies Centre in Sydney, Australia. The authors contend that the nature of strategic competition in the Indo-Pacific “demands a renewed approach to deterrence by the United States, Australia, and their allies and partners.” They specifically called for a more proactive strategy to deter gray-zone coercion that would “resist, deny, or punish coercion in an integrated way.”


The U.S. Indo-Pacific Strategy unveiled by U.S. President Joe Biden’s administration in February 2022 elaborates upon the concept of integrated deterrence announced by U.S. Defense Secretary Lloyd Austin in 2021. The strategy includes the concept of deterring gray-zone actions and coercion, which gives the issue more prominence than found in the 2019 version of the strategy. The 2019 strategy acknowledged Chinese gray-zone activities as incrementally changing the security posture but did not call for deterring them. It highlighted that allies and partners are force multipliers from the deterrence and warfighting perspectives. This amplification effect stems from the ability of allies and partners to operate seamlessly alongside U.S. joint forces, the result of efforts and investments to establish and maintain interoperability in tactics, communications and weapons systems.

Austin addressed the importance of allies and partners in the new strategy, explaining that “integrated deterrence also means working with partners to deter coercion and aggression across the spectrum of conflict, including the so-called gray zone.” The 2022 U.S. Indo-Pacific Strategy called for developing “initiatives that reinforce deterrence and counter coercion, such as opposing efforts to alter territorial boundaries or undermine the rights of sovereign nations at sea.” It also included an action plan to be accomplished by early 2024, providing a sense of urgency and immediacy to the task.

A major impetus for integrated deterrence is the need to manage the risk of unexpected effects and outcomes of deterrence operations that are not fully integrated across the U.S. government and with allies and partners. “U.S. deterrence efforts focused on one potential adversary may have undesired and unforeseen second and third order effects on our assurance, dissuasion, and deterrence efforts focused on other actors,” the U.S. Defense Department noted in its 2006 “Deterrence Operations: Joint Operating Concept.” The U.S. military’s geographic combatant commands must ensure that they integrate deterrence with each other, as well as with allies and partners in their respective areas of responsibility. U.S. Indo-Pacific Command (USINDOPACOM), for example, shares a common threat in Russia, which, of course, is a core focus of U.S. European Command and U.S. Strategic Command. The PRC’s ever-expanding global presence, meanwhile, requires all combatant commands to contribute to the integrated deterrence effort led by USINDOPACOM.

A U.S. Air Force B-2 Spirit bomber flies in formation with fighter aircraft of the Royal Australian Air Force and the U.S. Air Force during a March 2022 bilateral training mission in support of a Free and Open Indo-Pacific. TECH SGT. HAILEY HAUX/U.S. AIR FORCE

Implementing integrated deterrence with a focus on gray-zone actions and coercion requires developing clear theater-level concepts and objectives that target the behaviors of the PRC and Russia. The 2006 U.S. Joint Operating Concept provided the guidance and framework for developing deterrence objectives and effective deterrence operations. It specifically addressed the threat of gray-zone operations, explaining that deterrence constructs must have the flexibility to serve as a hedge “against the possibility that an adversary might incorrectly perceive their actions to be ‘below the radarscope’ of U.S. resolve and response.”

Changing these perceptions requires clarity of messaging and operations to counter and blunt gray-zone actions. Regarding the execution of the deterrence concept, Dr. Mara Karlin, U.S. assistant secretary of defense for strategy, plans and capabilities, has argued that deterrence activities “must be regular, so the Pentagon routinely considers the impact of its deterrence-related decisions.” Second, they must “be rigorous to ensure all relevant parties respect their findings, even if they disagree with them. And lastly, [they] must be clear-eyed.” As Adm. Sam Paparo, commander of U.S. Pacific Fleet, remarked at the Navy League Sea, Air, and Space Symposium in April 2022, effectively communicating the U.S. deterrence message is the line of operation that “encompasses all” of the deterrence effort in terms of changing adversary perceptions of national, alliance and coalition will and capabilities.

The Joint Operating Concept reinforces this, explaining that deterrence must be woven into daily operations, which means it must be reflected in campaign plans and orders, crisis response plans and all phases of conflict planning. The U.S. Defense Department document makes clear that peacetime campaign activities should be the building blocks for deterrence operations, and that peacetime deterrence operations must be able “to extend through crisis, armed conflict, escalation/de-escalation, war termination, and post-hostilities activities.”

U.S. Secretary of State Antony Blinken discusses the new U.S. Indo-Pacific Strategy during a speech in Jakarta, Indonesia. THE ASSOCIATED PRESS

Integration with other elements of national power and with allies is necessary to present adversaries with multiple challenges simultaneously. If military components of power are not clearly part of a broader integrated deterrence, retired U.S. Air Force Col. Thomas A. Drohan has written, then “operations such as demonstrations of force, freedom of navigation operations and multilateral exercises, and military relations with Chinese leaders, are unlikely to change China’s behavior.” Likewise, deterrence operations built on nonmilitary means that are not reinforced by a clear, perceivable and relevant element of military power are likely to fail. For example, countering the PRC’s legal warfare, or lawfare, by citing international norms and laws has failed to deter its territorial expansion, Aurelia George Mulgan, an expert in Japanese politics and Northeast Asian security issues at Australia’s University of New South Wales, noted in an article for The Diplomat magazine.

Likewise, countering gray-zone activities such as the illegal, unreported and unregulated fishing by the PRC’s massive fishing fleet — the world’s worst offender, according to the Geneva-based Global Initiative against Transnational Organized Crime — requires integrated approaches. To combat this form of economic warfare, the U.S. employs adaptive force packaging that combines the U.S. Navy’s military power with the U.S. Coast Guard’s law enforcement authority, presenting a visible deterrence activity and capability.

The military element of power is essential for any deterrence strategy. The Pentagon identified the PRC as the “No. 1 pacing challenge” for the U.S. and, in 2020, unveiled the Pacific Deterrence Initiative to identify and implement the force posture and capabilities required for deterrence in the region. Adversaries will assess the effectiveness of the force posture changes and capability improvements, but the military component of deterrence must be made clear. This may be represented in the form of fielded forces; bilateral and multilateral exercises (and the attendant increases in interoperability); demonstrations of relevant capabilities in experiments and exercises; and financial investment in critical warfighting capabilities. The last of these is evident in the U.S. government’s funding of Pacific Deterrence Initiative priorities to enhance force posture, multidomain training, experimentation and theater missile defense.


Cooperative partnerships with like-minded nations are critical for national, regional and global security. The 2019 Indo-Pacific Strategy highlighted the necessity of integrating the contributions of allies and partners into collective security. Through that strategy, the U.S. committed to reinforcing established alliances and partnerships while seeking to develop mutually beneficial cooperative frameworks to enhance collective security. In their report that year for the United States Studies Centre, Santoro, Thomas-Noone and Townshend noted that deterrence efforts and operations, if coordinated and integrated with allies and partners, can “diffuse the costs of Chinese actions and multiply the impact of individual nations’ deterrence strategies.”

Taiwan Armed Forces units conduct a live-fire drill to deter a coastal landing force during Han Kuang in September 2021. The five-day exercise prepares the military for a potential invasion of the self-governed island by the People’s Republic of China. THE ASSOCIATED PRESS

In 2020, then-U.S. Defense Secretary Mark Esper elevated the planning and supervision of efforts to develop alliances and partnerships with publication of the Guidance for Development of Alliances and Partnerships. The guidance provides “the foundational direction and priorities for achieving a coordinated strategic approach with our allies and partners,” according to the Joint Chiefs of Staff. Its purpose is to ensure the U.S. Defense Department sustains long-term strategic advantage through more coordinated, competitive efforts, leveraging the inherent strengths of the department’s relationships. Guidance priorities include a more coordinated force planning methodology “to help coordinate ally and partner militaries’ force development for more capable future forces.”

The U.S. Strategic Framework for the Indo-Pacific, developed in 2018 by the U.S. National Security Council and declassified in 2021 (in part, to explicitly communicate U.S. intentions and to deter the PRC from invading Taiwan), noted that strong alliances are essential to deter aggression and prevent open warfare. It also addressed the threat of coercion and malign influence by offering assistance to other Indo-Pacific nations in countering the PRC’s intelligence, espionage, clandestine and influence operations against their sovereign territory. The 2022 U.S. Indo-Pacific Strategy builds upon this and other previous frameworks and guidance to rely upon the collective capacity of allies and partners for deterrence.

Integrated deterrence requires investment in building collective capacity, nation by nation, with resources that can support a coalition. Countering the PRC’s efforts to expand its sphere of influence requires “rallying greater multilateral resistance to Chinese power, even at the cost of a tenser, more militarized Asia,” Hal Brands, a professor of global affairs at the Johns Hopkins School of Advanced International Studies and a former special assistant to the U.S. defense secretary for strategic planning, wrote in National Review in March 2022. The 2022 U.S. Indo-Pacific Strategy broadened the scope of relevant allies and partners and acknowledged heightened expectations for “European partners even on the most high-stakes areas of disagreement with China, like the future of Taiwan,” Vikram J. Singh, a senior advisor to the U.S. Institute of Peace’s Asia Program, noted in a March 2022 commentary for the institute’s website. If deterrence efforts are to be fully integrated, allies and partners must play more prominent roles, and the U.S. must be ready to facilitate such efforts.

Interoperability, too, is a key component of collective capacity and, thus, directly supports deterrence. “Across the region, the United States will work with allies and partners to deepen our interoperability and develop and deploy advanced warfighting capabilities as we support them in defending their citizens and their sovereign interests,” the 2022 U.S. Indo-Pacific Strategy noted. As stated previously, allies and partners are force multipliers. “The deterrent impact of such cooperation and integration is both political and military in nature,” the Pentagon’s Joint Operating Concept noted, with the political impacts being “primarily derived from the effects that coalition-based responses have on adversary decision-makers’ perceptions of U.S. and allied political will.”

Integrated contingency planning among key allies is one recommended approach to demonstrate combined opposition to a potential PRC invasion of Taiwan. Deterrence efforts against the PRC’s coercion and gray-zone actions must be balanced alongside conventional deterrence against other threats, including the possible resumption of Chinese attacks on Indian forces along the nations’ disputed Himalayan border, known as the Line of Actual Control. As allied and partner interoperability improves, it will factor into the CCP’s decision-making on whether to spark a war of choice.


The importance of getting it right is captured in a 2018 observation by Rand Corp. analyst Mike Mazarr. Deterrence failures are easier to spot than deterrence successes, as the absence of war does not necessarily mean that deterrence is working. However, when war breaks out, it is fair to analyze where a deterrence strategy went wrong. The yearlong “sitzkrieg” of Russia’s coercive force deployments along the borders of Ukraine provided ample time to mount effective deterrence operations and efforts to prevent a Russian invasion, and yet Russia was not deterred. In his testimony before the U.S. House Armed Services Committee, Gen. Tod Wolters, commander of U.S. European Command, admitted that the U.S. strategy to deter Russia from invading Ukraine had failed. U.S. Rep. Mike Gallagher made the same arguments before the committee and in an opinion article in The Wall Street Journal newspaper.

Alongside deterrence operations undergirded with credible military capabilities and will, the U.S. must also reassure allies and partners that it has their back in helping ensure their security. If the U.S. offers no pushback to adversary gray-zone actions and coercion, allies and partners may lose confidence and begin to hedge their bets, rather than stand firmly against the military threat. For example, the Philippines lost control of Scarborough Shoal in June 2012 following a U.S.-negotiated mutual withdrawal that only Manila observed, leaving the PRC in possession of Philippine territory. The standoff, which began two months earlier, resulted in consultations between the U.S. and Philippine governments in Washington, D.C., but the U.S. was not clear whether the U.S.-Philippine Mutual Defense Treaty covered Philippine-controlled islands in the South China Sea, which contributed to ambiguity about whether the U.S. would intervene directly if needed. The Philippines expected more support and sought to maximize U.S. involvement in resolving the crisis, but the PRC seized control of the shoal after dispatching greater force to displace Philippine vessels, according to the Asia Maritime Transparency Initiative. In 2014, the Chinese defense ministry publicly stated that the shoal is part of “China’s inherent territory.” Such assurance failures discredit future deterrence efforts.

Acknowledging that allies and partners will draw conclusions about Washington’s reliability as a security partner from the experience of others, President Biden’s administration has been assuring them of the U.S.’s commitment. In August 2022, for example, Secretary of State Antony Blinken assured Manila that the U.S. would come to its defense if the Philippines was attacked in the South China Sea, Reuters reported. Blinken said the nations’ Mutual Defense Treaty is ironclad. “An armed attack on Philippine Armed Forces, public vessels and aircraft will invoke U.S. mutual defense commitments under that treaty,” Blinken said. “The Philippines is an irreplaceable friend, partner and ally to the United States.”

For integrated deterrence to prevail, there must be a multiyear campaign that is coordinated with allies and partners and collectively assessed and refined to increasingly complicate the PRC’s calculus and decision-making regarding aggression. Adversaries need to see an effective capability that is positioned where it can impose costs, operated by competent and trained forces, and backed by a clearly articulated national will and commitment. As retired U.S. Army Gen. Jack Keane remarked during a March 2022 broadcast on Fox Business: “We truly have to establish an effective military deterrence. It is not enough to have a large military power on paper and not have it deployed to where the threat is.”

“Deterrence is not ‘waged’ in a vacuum,” as the 2006 U.S. Defense Department’s Joint Operating Concept explained. It requires a strategy supported by deterrence operations concepts and clear deterrence objectives. Paparo reinforced this in his April 2022 remarks, noting that “deterrence is not an activity [by itself], but it is an outcome” and a necessity for preserving a Free and Open Indo-Pacific.  

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