In Defense of Conventional Punishment: Why Japan’s Defensive Realism Requires Offensive Capability
The MOC
By
Will Kielm
October 22, 2024
After nearly eight decades spent maintaining a strict self-defense posture since World War Two, Japan made a pivotal shift in its grand strategy in December 2022. The government introduced a landmark National Security Strategy which made a significant political commitment to acquiring long-range “counterstrike capabilities”, which are traditionally viewed as “offensive capabilities”. Despite its historical commitment to the senshu boei (exclusively self-defense) principle, Japan has incrementally reinterpreted Article 9 of its constitution to broaden the concept of self-defense over the years. Most recently it took steps to acquire previously out-of-bounds counterstrike capabilities, driven largely by China’s military modernization and North Korea’s escalating nuclear provocations.
Although the People’s Republic of China (PRC) and North Korea have often labeled these developments as aggressive, the characterization is predictably one-sided. Both China and North Korea have developed offensive capabilities of their own while touting their ostensible defensive purposes. However, in the Indo-Pacific offensive and defensive capabilities are generally indistinguishable. Japan must recognize that purely defensive technologies are insufficient to ensure its own security and uphold the rules-based regional order. To credibly deter revisionist powers armed with offensive capabilities, Japan must move beyond the flawed mindset that draws a sharp distinction between offensive defense and defensive defense and strategically shift towards the acquisition of counterstrike capabilities that can impose significant costs on potential aggressors.
The Debate on Perception and the Offense-Defense Distinction
Understanding Japan’s definition of “self-defense” and examining its shift from defense to offense evokes two of the most fundamental conceptual questions in international relations: 1) can a state enhance its military capabilities with purely defensive intentions without being perceived as the aggressor? and 2) to what extent can states reliably distinguish between offensive and defensive capabilities? The first question touches upon what political scientists refer to as the “security dilemma”, a concept John Herz described in 1950 as a situation where the pursuit of security leads states to accumulate power, increasing the insecurity of others. This “dilemma” triggers a vicious cycle of power competition, where no state can ever feel entirely secure. Scholars have long contended that, despite a state’s non-aggressive intentions driven solely by security concerns, its military buildup may still be perceived as aggressive by others. In its pursuit of greater security, a state may ultimately be seen as driven not only by defense but also by “greed”—such as economic gain, prestige, historical claims, domestic pressures, or ideology.
The late political scientist Robert Jervis in 1976 cited Germany’s naval expansion under Kaiser Wilhelm II in the late nineteenth and early twentieth centuries as one historical example of the security dilemma. Although Germany claimed its fleet buildup was intended for defensive purposes and to protect its growing overseas empire, London perceived Berlin’s actions as a direct challenge to British naval supremacy, contributing to rising tensions between the two countries and the eventual outbreak of World War One. Similarly, when the Soviet Union deployed missiles in Cuba during the Cuban Missile Crisis of 1962, Moscow framed the move as a defensive measure to deter future U.S. aggression. Nevertheless, the United States perceived Moscow’s decision as highly offensive, heightening tensions to the brink of nuclear war.
Some scholars, however, argue that states can strengthen their militaries without being misperceived as aggressors. By focusing entirely on defensive capabilities during a military buildup, states can credibly signal that their motives are driven by security concerns alone, thereby achieving what is known as a defense-dominant posture within the “offense-defense balance”. This approach provides credible reassurances to potential adversaries that their actions are driven by security concerns rather than aggressive intent. As George Quester once famously argued, “Defensive developments in military practice will be more welcome than offensive ones, simply because they make war less likely among such states.” These scholars are known as “defensive realists” and emphasize the importance of maintaining a balance of power (or a balance of “threats“) that favors defense to avoid an escalatory spiral between great powers.
Numerous defensive realists have argued that defensive weapons are distinguishable from offensive ones and that states can enhance their security without threatening others. Charles Glaser and Chaim Kaufmann offer an objective measurement of the offense-defense balance: states can treat the balance as the ratio of the cost of the forces the attacker requires to take territory to the cost of the forces the defender has deployed. Only by acknowledging this offense-defense distinction and focusing exclusively on defensive as opposed to offensive military technologies can states avoid the so-called “cult of the offensive”—as Stephen Van Evera warned—and thereby prevent a careless escalation spiral that could lead to a costly war.
This line of optimistic, defensive realist analyses that draw an artificial distinction between offensive and defensive capabilities has been contested in the political science literature. For instance, Keir Lieber in 2005 empirically demonstrated that the variance between offensive and defensive advantages is very rarely significant and that variables other than military technologies—namely the distribution of power and difference in military doctrine and strategy—are far more likely to determine military outcomes. Even John Mearsheimer, one of the leading proponents of foreign policy restraint among academics, acknowledged the difficulty of distinguishing defensive and offensive capabilities, which forces states to aggressively and indiscriminately pursue military power to cause security for themselves.
Such indistinguishability between offensive and defensive capabilities nullifies the security dilemma, leaving Japan with a straightforward path. Instead of managing escalation through defensive technologies, Japan must focus on achieving deterrence and escalation dominance, which necessitates the embrace of acquiring counterstrike capabilities.
This is the first part of a two-part series. The second part of this essay will be published on Tuesday.
_______________
This is the second part of a two-part series. The first part of this essay can be read here.
Current Challenges for Japan’s Security and the Need for Offensive Defense
In the context of Japan and the broader security challenges posed by China in the Indo-Pacific, two critical questions arise: first, does China harbor revisionist political intentions? Second, is China’s military buildup defensive or offensive in nature?
While the answer to the first question remains subject to debate, there are several indicators that point to China’s intentions—its stated goal to achieve “the great rejuvenation of the Chinese nation” by 2049; its vast, opaque program of military expansion; and its increasingly aggressive actions in Taiwan and the South China Sea. This also includes the acquisition of what numerous scholars consider to be “offensive capabilities”, such as the Type 075 Amphibious Assault Ships, the Liaoning and Shandong Aircraft Carriers, and the J-20 stealth fighter jets—all of which are designed to project Chinese military power far from its shores.
These indicators suggest that China is a dissatisfied great power that seeks to politically and militarily expand its influence beyond its borders. As highlighted in the 2022 U.S. National Security Strategy, China stands as the only competitor to the United States with both “the intent to reshape the international order” and the “economic, diplomatic, military, and technological power to achieve that goal”.
On the second question, some scholars, such as Eugene Gholz, contend that China’s military buildup is defensive in nature. Namely, they argue that China’s anti-access/area denial (A2/AD) strategy is primarily defensive and not suited for offensive goals, countering claims that it poses a significant threat. They also highlight those geographic limitations—including distance, radar obstructions from islands, and the reduced effectiveness of missiles over long ranges—which would hinder A2/AD’s offensive potential. Even though they acknowledge that A2/AD forces may be relevant in conflict scenarios involving Taiwan or the Senkaku Islands, they advocate for a strategy of deterrence by denial purely rooted in a defensive posture rather than integrating offensive capabilities.
At the core of the argument is the distinction between deterrence by denial, which Glenn Snyder argued results from the “capacity to deny territorial gains to the enemy”, and deterrence by punishment, which refers to the threat of imposing costs on the attacker. Proponents of the offense-defense framework have predominantly favored deterrence by denial, contending that deterrence by punishment, which involves the threat of offensive action, is inherently provocative.
In that line, they warn that offensive preparations might provoke unnecessary escalation risks and argue that the United States and its allies should prioritize defensive military strategies to avoid provoking China into pursuing an offensive buildup. While defensive realists highlight China’s “defensive capabilities” to portray China as a purely defensive power, they are prompt to identify the scant, nascent set of defensive capabilities that Japan had acquired as offensive—namely its reliance on a “forward defense” approach, which emphasizes fighter aircraft, destroyers, and ground forces. They also claim that Japan’s acquisition of long-range missile strike capabilities, aiming to preemptively threaten North Korea’s ballistic missile launches or retaliate against China, are offensive technologies that could be “perceived as offensive defense”. However, these critics are wrong to draw this false offense-defense dichotomy, and it is safer to assume for several reasons that offensive and defensive capabilities are largely indistinguishable in the Indo-Pacific.
To begin with, even the most purely “defensive technologies” can paradoxically enhance offensive operations, thereby shifting the offense-defense balance in favor of offense. For example, the deployment of the U.S. deployment of the Terminal High Altitude Area Defense (THAAD) system on the Korean Peninsula—a purely defensive technology designed to intercept and neutralize incoming ballistic missiles—drew strong criticism from China on the grounds that the system would undermine the principles of Mutual Assured Destruction and second-strike capability. As Alfred Thayer Mahan also astutely observed: in operations involving both fleets and coastal fortresses—particularly in combined naval and military engagements—even the function of a sea-coast fortress is fundamentally offensive.
Moreover, revisionist powers have the incentive to portray even the most purely offensive capabilities as defensive, rendering any declaration of “defensive intent” a form of cheap talk. Very rarely do great powers present their militaries as being for offensive purposes. This misdirection allows states to obscure their true intentions under the guise of self-defense, thereby garnering domestic and international legitimacy for their actions. By framing their military buildups or aggressive moves as necessary defensive measures, these states can avoid provoking preemptive responses from other powers while still pursuing expansionist or revisionist goals. Even the most aggressive revisionist powers have historically justified their conquests as acts of “self-defense”, which is why no government has ever established a “Department of Offense”.
Additionally, since any short- or medium-term contingencies in the Indo-Pacific are expected to be predominantly naval, the utility of the offense-defense balance framework is diminished. In naval warfare, the distinction between offensive and defensive capabilities is much more ambiguous than it is on the land. Unlike land warfare, where terrain and fortifications can offer protection and impede offensive operations, naval engagements are largely determined by material superiority—such as advanced ships and cutting-edge technology—rather than positional advantage. The open sea provides little cover or concealment, rendering ships particularly reliant on and vulnerable to superior firepower, which in turn makes naval battles more decisive and their outcomes one-sided than land battles. This vulnerability gives an inherent advantage to the side that strikes first, blurring the lines between offense and defense and complicating the offense-defense balance. Such need for offensive capabilities in naval warfare is also strongly reflected in the existing scholarship as advanced by Stephen Biddle, who argued that maritime security inherently requires an offensive edge due to the pronounced first-mover advantage in naval warfare.
Recognizing the offense-defense indistinguishability in the Indo-Pacific leads to two critical implications. First, attempting to infer China’s strategic intentions solely based on whether its capabilities are defensive or offensive is futile since defensive technologies in its arsenal can easily be repurposed for offensive objectives. Instead, it is far more worthwhile to understand the Chinese Communist Party’s political motivations by analyzing their leadership, history of revisionism, and other structural factors that shape their intentions. It is critical to recognize that political objectives typically dictate their military capabilities, which serve as instruments to achieve those goals, rather than the reverse.
Second, Japan should prioritize maximizing its military capabilities to enhance deterrence rather than handicap its power in the name of de-escalation or the avoidance of being misperceived as an aggressor. While the prevailing view that deterrence by denial is more effective than deterrence by punishment holds merit, it is critical to acquire the counterstrike capabilities to credibly threaten punishment in conjunction with existing denial capabilities to limit China’s ability to conduct offensive operations by increasing both the credibility and ability to incur punishment against the PRC in wartime. Recognizing that China’s capabilities—whether labeled as offensive or defensive—should be assumed to serve offensive purposes, Japan’s focus should be exclusively on maximizing its military power to ensure its security and achieve credible deterrence at the operational level.
The Next Step for Japan: Acquiring Counterstrike for Punishment and Denial
For Japan, the acquisition of counterstrike capabilities serves a clear purpose: to deter potential aggressors by not only enabling denial operations but also by positioning the country to credibly punish limited military actions from China. Moreover, deterrence by punishment does not need to rely on counter-value strategies. As Robert Powell argued, offensive capabilities can strengthen both punitive and denial strategies, even though they are conceptually distinct. This suggests that, despite China and North Korea being nuclear powers, conventional deterrence can remain credible without escalating to the level of nuclear conflict. Powell also noted that limited attacks can serve as effective deterrence if a state can “impose high enough costs on an adversary that it would rather back down than endure the punishment” while ensuring that “the adversary still has something to lose”.
To achieve this, Japan must collaborate closely with the United States and other regional partners to build its defense industrial capacity, enabling the production of a substantial stockpile of long-range precision-guided missiles—such as Tomahawk cruise missiles and hypersonic weapons—while also developing or acquiring advanced launching platforms, including ground-based missile systems and upgraded aircraft like the F-35. Japan must also leverage the new command-and-control structures to jointly plan deep-strike operations and escalation control with its U.S. counterparts in the newly reconstituted United States Forces Japan / Joint Force Headquarters. This effort will require strong political will and additional Diet deliberations to establish the legal mechanisms necessary for a broader reinterpretation of senshu boei.
Japan’s shift toward acquiring offensive capabilities is a necessary response to the increasingly complex security environment in the Indo-Pacific. The blurred distinction between offensive and defensive capabilities, particularly in naval warfare, makes it crucial for Japan to enhance its deterrence posture. Restricting Japan’s military to purely defensive measures ignores strategic realities and risks undermining its security. To safeguard both Japanese and broader regional security, Tokyo must prioritize acquiring offensive capabilities that pave the way for effective deterrence by denial and punishment in the long term.
Will Kielm is a Research Fellow at the Edwin O. Reischauer Center for East Asian Studies at the Johns Hopkins School of Advanced International Studies (SAIS). He recently graduated from the University of Michigan’s Gerald R. Ford School of Public Policy.
The views expressed in this piece are the sole opinions of the author and do not necessarily reflect those of the Center for Maritime Strategy or other institutions listed.
Center for Maritime Strategy
By Will Kielm
After nearly eight decades spent maintaining a strict self-defense posture since World War Two, Japan made a pivotal shift in its grand strategy in December 2022. The government introduced a landmark National Security Strategy which made a significant political commitment to acquiring long-range “counterstrike capabilities”, which are traditionally viewed as “offensive capabilities”. Despite its historical commitment to the senshu boei (exclusively self-defense) principle, Japan has incrementally reinterpreted Article 9 of its constitution to broaden the concept of self-defense over the years. Most recently it took steps to acquire previously out-of-bounds counterstrike capabilities, driven largely by China’s military modernization and North Korea’s escalating nuclear provocations.
Although the People’s Republic of China (PRC) and North Korea have often labeled these developments as aggressive, the characterization is predictably one-sided. Both China and North Korea have developed offensive capabilities of their own while touting their ostensible defensive purposes. However, in the Indo-Pacific offensive and defensive capabilities are generally indistinguishable. Japan must recognize that purely defensive technologies are insufficient to ensure its own security and uphold the rules-based regional order. To credibly deter revisionist powers armed with offensive capabilities, Japan must move beyond the flawed mindset that draws a sharp distinction between offensive defense and defensive defense and strategically shift towards the acquisition of counterstrike capabilities that can impose significant costs on potential aggressors.
The Debate on Perception and the Offense-Defense Distinction
Understanding Japan’s definition of “self-defense” and examining its shift from defense to offense evokes two of the most fundamental conceptual questions in international relations: 1) can a state enhance its military capabilities with purely defensive intentions without being perceived as the aggressor? and 2) to what extent can states reliably distinguish between offensive and defensive capabilities? The first question touches upon what political scientists refer to as the “security dilemma”, a concept John Herz described in 1950 as a situation where the pursuit of security leads states to accumulate power, increasing the insecurity of others. This “dilemma” triggers a vicious cycle of power competition, where no state can ever feel entirely secure. Scholars have long contended that, despite a state’s non-aggressive intentions driven solely by security concerns, its military buildup may still be perceived as aggressive by others. In its pursuit of greater security, a state may ultimately be seen as driven not only by defense but also by “greed”—such as economic gain, prestige, historical claims, domestic pressures, or ideology.
The late political scientist Robert Jervis in 1976 cited Germany’s naval expansion under Kaiser Wilhelm II in the late nineteenth and early twentieth centuries as one historical example of the security dilemma. Although Germany claimed its fleet buildup was intended for defensive purposes and to protect its growing overseas empire, London perceived Berlin’s actions as a direct challenge to British naval supremacy, contributing to rising tensions between the two countries and the eventual outbreak of World War One. Similarly, when the Soviet Union deployed missiles in Cuba during the Cuban Missile Crisis of 1962, Moscow framed the move as a defensive measure to deter future U.S. aggression. Nevertheless, the United States perceived Moscow’s decision as highly offensive, heightening tensions to the brink of nuclear war.
Some scholars, however, argue that states can strengthen their militaries without being misperceived as aggressors. By focusing entirely on defensive capabilities during a military buildup, states can credibly signal that their motives are driven by security concerns alone, thereby achieving what is known as a defense-dominant posture within the “offense-defense balance”. This approach provides credible reassurances to potential adversaries that their actions are driven by security concerns rather than aggressive intent. As George Quester once famously argued, “Defensive developments in military practice will be more welcome than offensive ones, simply because they make war less likely among such states.” These scholars are known as “defensive realists” and emphasize the importance of maintaining a balance of power (or a balance of “threats“) that favors defense to avoid an escalatory spiral between great powers.
Numerous defensive realists have argued that defensive weapons are distinguishable from offensive ones and that states can enhance their security without threatening others. Charles Glaser and Chaim Kaufmann offer an objective measurement of the offense-defense balance: states can treat the balance as the ratio of the cost of the forces the attacker requires to take territory to the cost of the forces the defender has deployed. Only by acknowledging this offense-defense distinction and focusing exclusively on defensive as opposed to offensive military technologies can states avoid the so-called “cult of the offensive”—as Stephen Van Evera warned—and thereby prevent a careless escalation spiral that could lead to a costly war.
This line of optimistic, defensive realist analyses that draw an artificial distinction between offensive and defensive capabilities has been contested in the political science literature. For instance, Keir Lieber in 2005 empirically demonstrated that the variance between offensive and defensive advantages is very rarely significant and that variables other than military technologies—namely the distribution of power and difference in military doctrine and strategy—are far more likely to determine military outcomes. Even John Mearsheimer, one of the leading proponents of foreign policy restraint among academics, acknowledged the difficulty of distinguishing defensive and offensive capabilities, which forces states to aggressively and indiscriminately pursue military power to cause security for themselves.
Such indistinguishability between offensive and defensive capabilities nullifies the security dilemma, leaving Japan with a straightforward path. Instead of managing escalation through defensive technologies, Japan must focus on achieving deterrence and escalation dominance, which necessitates the embrace of acquiring counterstrike capabilities.
This is the first part of a two-part series. The second part of this essay will be published on Tuesday.
_______________
This is the second part of a two-part series. The first part of this essay can be read here.
Current Challenges for Japan’s Security and the Need for Offensive Defense
In the context of Japan and the broader security challenges posed by China in the Indo-Pacific, two critical questions arise: first, does China harbor revisionist political intentions? Second, is China’s military buildup defensive or offensive in nature?
While the answer to the first question remains subject to debate, there are several indicators that point to China’s intentions—its stated goal to achieve “the great rejuvenation of the Chinese nation” by 2049; its vast, opaque program of military expansion; and its increasingly aggressive actions in Taiwan and the South China Sea. This also includes the acquisition of what numerous scholars consider to be “offensive capabilities”, such as the Type 075 Amphibious Assault Ships, the Liaoning and Shandong Aircraft Carriers, and the J-20 stealth fighter jets—all of which are designed to project Chinese military power far from its shores.
These indicators suggest that China is a dissatisfied great power that seeks to politically and militarily expand its influence beyond its borders. As highlighted in the 2022 U.S. National Security Strategy, China stands as the only competitor to the United States with both “the intent to reshape the international order” and the “economic, diplomatic, military, and technological power to achieve that goal”.
On the second question, some scholars, such as Eugene Gholz, contend that China’s military buildup is defensive in nature. Namely, they argue that China’s anti-access/area denial (A2/AD) strategy is primarily defensive and not suited for offensive goals, countering claims that it poses a significant threat. They also highlight those geographic limitations—including distance, radar obstructions from islands, and the reduced effectiveness of missiles over long ranges—which would hinder A2/AD’s offensive potential. Even though they acknowledge that A2/AD forces may be relevant in conflict scenarios involving Taiwan or the Senkaku Islands, they advocate for a strategy of deterrence by denial purely rooted in a defensive posture rather than integrating offensive capabilities.
At the core of the argument is the distinction between deterrence by denial, which Glenn Snyder argued results from the “capacity to deny territorial gains to the enemy”, and deterrence by punishment, which refers to the threat of imposing costs on the attacker. Proponents of the offense-defense framework have predominantly favored deterrence by denial, contending that deterrence by punishment, which involves the threat of offensive action, is inherently provocative.
In that line, they warn that offensive preparations might provoke unnecessary escalation risks and argue that the United States and its allies should prioritize defensive military strategies to avoid provoking China into pursuing an offensive buildup. While defensive realists highlight China’s “defensive capabilities” to portray China as a purely defensive power, they are prompt to identify the scant, nascent set of defensive capabilities that Japan had acquired as offensive—namely its reliance on a “forward defense” approach, which emphasizes fighter aircraft, destroyers, and ground forces. They also claim that Japan’s acquisition of long-range missile strike capabilities, aiming to preemptively threaten North Korea’s ballistic missile launches or retaliate against China, are offensive technologies that could be “perceived as offensive defense”. However, these critics are wrong to draw this false offense-defense dichotomy, and it is safer to assume for several reasons that offensive and defensive capabilities are largely indistinguishable in the Indo-Pacific.
To begin with, even the most purely “defensive technologies” can paradoxically enhance offensive operations, thereby shifting the offense-defense balance in favor of offense. For example, the deployment of the U.S. deployment of the Terminal High Altitude Area Defense (THAAD) system on the Korean Peninsula—a purely defensive technology designed to intercept and neutralize incoming ballistic missiles—drew strong criticism from China on the grounds that the system would undermine the principles of Mutual Assured Destruction and second-strike capability. As Alfred Thayer Mahan also astutely observed: in operations involving both fleets and coastal fortresses—particularly in combined naval and military engagements—even the function of a sea-coast fortress is fundamentally offensive.
Moreover, revisionist powers have the incentive to portray even the most purely offensive capabilities as defensive, rendering any declaration of “defensive intent” a form of cheap talk. Very rarely do great powers present their militaries as being for offensive purposes. This misdirection allows states to obscure their true intentions under the guise of self-defense, thereby garnering domestic and international legitimacy for their actions. By framing their military buildups or aggressive moves as necessary defensive measures, these states can avoid provoking preemptive responses from other powers while still pursuing expansionist or revisionist goals. Even the most aggressive revisionist powers have historically justified their conquests as acts of “self-defense”, which is why no government has ever established a “Department of Offense”.
Additionally, since any short- or medium-term contingencies in the Indo-Pacific are expected to be predominantly naval, the utility of the offense-defense balance framework is diminished. In naval warfare, the distinction between offensive and defensive capabilities is much more ambiguous than it is on the land. Unlike land warfare, where terrain and fortifications can offer protection and impede offensive operations, naval engagements are largely determined by material superiority—such as advanced ships and cutting-edge technology—rather than positional advantage. The open sea provides little cover or concealment, rendering ships particularly reliant on and vulnerable to superior firepower, which in turn makes naval battles more decisive and their outcomes one-sided than land battles. This vulnerability gives an inherent advantage to the side that strikes first, blurring the lines between offense and defense and complicating the offense-defense balance. Such need for offensive capabilities in naval warfare is also strongly reflected in the existing scholarship as advanced by Stephen Biddle, who argued that maritime security inherently requires an offensive edge due to the pronounced first-mover advantage in naval warfare.
Recognizing the offense-defense indistinguishability in the Indo-Pacific leads to two critical implications. First, attempting to infer China’s strategic intentions solely based on whether its capabilities are defensive or offensive is futile since defensive technologies in its arsenal can easily be repurposed for offensive objectives. Instead, it is far more worthwhile to understand the Chinese Communist Party’s political motivations by analyzing their leadership, history of revisionism, and other structural factors that shape their intentions. It is critical to recognize that political objectives typically dictate their military capabilities, which serve as instruments to achieve those goals, rather than the reverse.
Second, Japan should prioritize maximizing its military capabilities to enhance deterrence rather than handicap its power in the name of de-escalation or the avoidance of being misperceived as an aggressor. While the prevailing view that deterrence by denial is more effective than deterrence by punishment holds merit, it is critical to acquire the counterstrike capabilities to credibly threaten punishment in conjunction with existing denial capabilities to limit China’s ability to conduct offensive operations by increasing both the credibility and ability to incur punishment against the PRC in wartime. Recognizing that China’s capabilities—whether labeled as offensive or defensive—should be assumed to serve offensive purposes, Japan’s focus should be exclusively on maximizing its military power to ensure its security and achieve credible deterrence at the operational level.
The Next Step for Japan: Acquiring Counterstrike for Punishment and Denial
For Japan, the acquisition of counterstrike capabilities serves a clear purpose: to deter potential aggressors by not only enabling denial operations but also by positioning the country to credibly punish limited military actions from China. Moreover, deterrence by punishment does not need to rely on counter-value strategies. As Robert Powell argued, offensive capabilities can strengthen both punitive and denial strategies, even though they are conceptually distinct. This suggests that, despite China and North Korea being nuclear powers, conventional deterrence can remain credible without escalating to the level of nuclear conflict. Powell also noted that limited attacks can serve as effective deterrence if a state can “impose high enough costs on an adversary that it would rather back down than endure the punishment” while ensuring that “the adversary still has something to lose”.
To achieve this, Japan must collaborate closely with the United States and other regional partners to build its defense industrial capacity, enabling the production of a substantial stockpile of long-range precision-guided missiles—such as Tomahawk cruise missiles and hypersonic weapons—while also developing or acquiring advanced launching platforms, including ground-based missile systems and upgraded aircraft like the F-35. Japan must also leverage the new command-and-control structures to jointly plan deep-strike operations and escalation control with its U.S. counterparts in the newly reconstituted United States Forces Japan / Joint Force Headquarters. This effort will require strong political will and additional Diet deliberations to establish the legal mechanisms necessary for a broader reinterpretation of senshu boei.
Japan’s shift toward acquiring offensive capabilities is a necessary response to the increasingly complex security environment in the Indo-Pacific. The blurred distinction between offensive and defensive capabilities, particularly in naval warfare, makes it crucial for Japan to enhance its deterrence posture. Restricting Japan’s military to purely defensive measures ignores strategic realities and risks undermining its security. To safeguard both Japanese and broader regional security, Tokyo must prioritize acquiring offensive capabilities that pave the way for effective deterrence by denial and punishment in the long term.
Will Kielm is a Research Fellow at the Edwin O. Reischauer Center for East Asian Studies at the Johns Hopkins School of Advanced International Studies (SAIS). He recently graduated from the University of Michigan’s Gerald R. Ford School of Public Policy.
The views expressed in this piece are the sole opinions of the author and do not necessarily reflect those of the Center for Maritime Strategy or other institutions listed.