Examining Thresholds in an East-West War
The world has not witnessed a great power general war in nearly 80 years, and for most of the last 35 years, the prospect of such a war has been considered remote by most government officials. Today, however, there is a growing unease over the trajectory of global peace and security. A broad consensus is emerging in the United States and among other free world capitals that the revisionist ambitions of autocratic states—China, Russia, North Korea, a weakened but still dangerous Iran, Pakistan, and others—through their armament programs, coercive diplomacy, and aggression, may eventually compel Western powers, including Western-aligned Asian states such as Japan and South Korea, into a large-scale war.
The next National Defense Strategy must acknowledge the existential nature of this threat and commit to the aggressive rearmament of American military power—both qualitatively and quantitatively—to deter, and if necessary, win a multi-theater large-scale war against one or more of the authoritarian powers. This will require more than marginal force adjustments; it demands a systemic shift in U.S. defense posture, planning assumptions, strategic priorities, and allied interoperability.
Reciprocal Limits and the East-West Divide
Time will tell whether the free world’s rhetoric on rearmament and preparedness translates into a resurrection of Western military power. Regardless of how far the West progresses in rearmament and in reestablishing deterrence, the United States and its allies must revisit and modernize their thinking on thresholds in warfare. All wars, even the most violent and brutish, contain some reciprocal firebreaks, limits, or restraints on belligerent behavior. For example, all major powers during World War II refrained from using poison gas on the battlefield, despite its widespread use in World War I.
While some thresholds in warfare are broadly respected, others are unevenly observed or rejected by non-Western states. Examples of such uneven application include differing interpretations of Western-centric international humanitarian law jus ad bellum principles—such as initiating hostilities prior to a formal declaration of war and the employment of proxy forces, or jus in bello principles—including the treatment of prisoners and the subordination of collateral damage concerns in warfare. These inconsistencies are not exclusive to East-West conflicts; however, the divergence between Western values-based thresholds and the belief systems of Eastern powers is a matter of fact.
In the context of a potential East-West war, Western nations must confront the reality that their current threshold frameworks are largely Occidental in nature. The threshold assumptions developed during the Soviet-American Cold War are unlikely to be representative of today’s authoritarian powers, all of which follow an eastern strategic culture. While Russia historically straddled the East-West divide, it has increasingly aligned with the East in its multi-decade effort to reject the West.
Many Western officials continue to exhibit cultural naiveté toward non-Western nations, displaying an ineradicable flaw in their thinking by relying on outdated paradigms or mirror imaging their more culturally similar, post-modern normed cousins.
Two post-1990 examples illustrate the phenomenon on how the West has attempted to impose its thresholds on the broader international community: the Olso Convention banning cluster munitions and the Ottawa Convention banning antipersonnel landmines. The overwhelming majority of non-signatories to these arms control protocols—China, Russia, North Korea, Iran, India, Pakistan, etc.—are non-Western powers. The lone Western exceptions—the United States, South Korea and Israel—retained vestiges of realism that accepted large-scale conventional wars remain possible and that total battlefield sanitization is an unrealistic aspiration.
However, some European nations have recently woken up to the truism that hope is not a strategy and international protocols will not save them from large-scale war against authoritarian powers. Six European nations that share a border with Russia—Ukraine, Poland, Finland, Estonia, Latvia, and Lithuania—are abrogating, or have already withdrawn their involvement in the Ottawa Convention. Lithuania has taken the additional step by withdrawing from the Oslo Convention.
American attempts to promote mutual guardrails, such as hotlines and transparency mechanisms, often fail due to fundamental differences in values. Despite years of effort, Chinese leaders have shown little interest in reciprocating, reflecting their divergent strategic culture.
As the West considers how to approach thresholds in a future large-scale war with Eastern authoritarian powers, it must approach the issue through the lens of its potential adversaries. Only by understanding what those regimes believe and value can there be any hope of reaching even minimal accommodations on limiting escalation.
It is unlikely that any formal or even tacit agreement on wartime thresholds will emerge prior to conflict. Instead, thresholds will likely be established ad hoc, shaped by pre-war declaratory statements and self-imposed constraints after hostilities begin.
The credibility of Western declaratory statements has suffered from overuse of euphemisms and hollow red lines. Going forward, Western powers must clearly articulate where they intend to selectively impose limits—particularly in keeping a large-scale war conventional and primarily within the military domain—and back those limits with hard power and action, including robust escalation capabilities that are held in reserve to deter adversaries from breaching them.
Two thresholds demand the most serious attention: (1) the 80-year firebreak in nuclear weapon use, and (2) how the belligerents will conduct operations within each other’s homelands. If both sides do not reach some understanding about these domains, the risk increases for uncontrollable escalation that escapes the bounds of strategic management.
Preserving the Nuclear Firebreak
The West should anticipate Eastern authoritarian powers to employ hyperbolic rhetoric and threats to instill fear and hesitation among Western leaders and populations. Western states must be prepared ahead of conflict against authoritarian information warfare by better educating their citizens and by reestablishing effective emergency management and civil defense programs.
For over a generation, Western discourse on nuclear warfare has atrophied. Policy, doctrine, research, and training on nuclear conflict have been neglected under the assumption that nuclear warfare is obsolete. Feelings on nuclear weapons have led the United States and the West down the road of denial for too long. The nuclear landscape of 2025 is shaped by a coalition of Eastern autocracies with significant arsenals and lower thresholds for use, especially tactical nuclear weapons used coercively or in battle.
Much work is required to regenerate experience lost, develop and evaluate new strategic concepts, and to generate viable wartime nuclear options to carry peacetime nuclear deterrence into a large-scale war. The West should not make the mistake of limiting itself to dusting off first nuclear age materials on nuclear strategy and conventional-nuclear integration. Conditions have changed. Therefore, new thinking is required on conventional-nuclear-chemical-biological-space-cyber integration to not only deliver a more comprehensive deterrence package, but also create the underpinnings for Western military forces, particularly land forces, to fight to and through the opposing side’s defenses in order to reclaim lost territory or to seize key terrain deep in the theater of war. While the priority remains deterring nuclear use into and through an East-West war, the United States and its allies must also prepare for how it will re-establish the no-nuclear threshold if one of the authoritarian powers breach it.
American and other Western leaders must be trained and ready to manage escalation deliberately, developing scenarios to study alternatives tailored to the Eastern adversaries and their regime elites. If nuclear use occurs, the response must not only match but exceed the provocation, communicating clearly that it is in the adversary’s best interest to return to the pre-conflict nuclear taboo and perhaps open a pathway for war termination negotiations to begin.
Importantly, Western powers, led by the United States, will need to politically bind Beijing and Moscow to control their lesser and likely more risk prone allies (e.g. North Korea, Pakistan and possibly Iran in the future) by openly declaring that they will be held responsible for their fellow confederate’s nuclear breaches in time of war. The United States and the rest of the West must also be prepared to fight on a nuclear battlefield if one or more authoritarian powers end up operationalizing tactical nuclear weapons into their military campaigns.
Limiting War-making in Homelands
Beyond nuclear thresholds, how homelands will be treated in warfare is perhaps the second-most important consideration to examine in a large-scale war involving the great powers as belligerents. Certain types of war-making, especially non-nuclear counter-value targeting that causes mass civilian harm, carry a significantly heightened risk of uncontrollable escalation. These include: kinetic strikes on civilian infrastructure, mass terrorism, cyber-attacks on critical systems, biological warfare, and the use of electromagnetic tools.
The West will need to make clear to the autocrats that crossing such thresholds will trigger proportional or greater retaliatory actions, and must back this up with credible escalatory capabilities. To be believable, the West will need to develop a full suite of nuclear and non-nuclear retaliatory response capabilities that it could use in extreme situations.
In terms of nuclear capabilities, the U.S. nuclear triad must be modernized, diversified, and modestly expanded to reflect the emerging multipolar nuclear landscape. This includes air and ground delivered tactical weapons in quantities that are compelling to authoritarian powers that the United States is prepared and postured for battlefield nuclear warfare.
Non-nuclear capabilities are equally important for deterrence to be credible. Lacking credible non-nuclear retaliatory options risks leaving nuclear weapons as the only viable response, which is inherently destabilizing considering that the Eastern authoritarian powers have proven remarkably astute at operating inside the decision space of Western leaders. This may include developing more potent offensive artificial intelligence-enhanced cyber tools and electromagnetic weapon capabilities, fielding but not deploying space weapons such as fractional orbital bombardment systems, development of clandestine capabilities to infiltrate autonomous strike systems, researching and developing tectonic weapons, deploying area incendiary systems, and possibly resurrecting dormant biological and chemical programs.
It is in the interest of all the great powers to reach an accommodation on limiting where and how war-making will occur on each other’s respective homelands. The central challenge to such an accommodation is the complicated geographic realities of an East-West war. Some homelands will be adjacent to the theater of war, while others will not. It is unrealistic to expect homelands, particularly in the West, to remain sanctuaries, but that does not preclude establishing some constraints.
Subjugation or occupation of nuclear powers is not a plausible outcome; these wars will most probably end or temporarily pause through exhaustion or political accommodation. Therefore, it is possible to imagine limits on homeland targeting, at least among the great powers with the ability to greatly escalate to general war.
A practical approach may involve adopting a theater-of-war, counter-force model by restricting homeland strikes to military targets directly involved in combat operations, and avoiding civilian or dual-use infrastructure. Such a strategy should include geographically demarcated limitations to maintain clarity and reduce misunderstanding.
For instance, in a Chinese campaign to subjugate Taiwan, the U.S. might consider limiting combat operations to military forces in specific provinces in China (e.g., Zhejiang, Fujian, Guangdong, Hainan) directly involved in the campaign, while understanding that China would target U.S. military sites in allied countries, Guam, the Hawaiian Islands, Alaska and along the Pacific Coast. Both parties would refrain from strikes deeper in each other’s interiors, except under a modified “hot pursuit” doctrine—whereby forces operating from interior bases directly participating in the war could be targeted. As an example of how the hot-pursuit doctrine might be executed: China’s conventional rocket forces, airbases and naval ports (including air defense assets) taking active part in the war from bases in the Northern, Central and Western theater commands would be targetable, while U.S. bomber bases, naval bases and the air defense sites protecting them, etc. in the Continental interior of the United States taking active part in hostilities would similarly be targetable sites.
The West must remain clear-eyed about the reality that, while some reciprocal limits on warfare within homelands may be possible, the seizure of key and decisive terrain by land forces will likely be necessary for one side to compel war termination through political accommodation. This could include the occupation of homeland territory adjacent to the theater of war, outside the theater but integral to the war effort, or within its littorals. The integrated suite of Western capabilities required to deter unrestrained warfare in the homeland is the same set of capabilities needed to deter nuclear use, enable Western forces to penetrate the theater, seize critical terrain, and ultimately end the war on favorable terms.
Ultimately, thresholds around homeland targeting will be highly dependent on the scope of the war and how it begins. A deliberately localized conflict or one sparked by tensions and before it escalates may allow for the emergence of tacit limits. However, a war initiated by a sudden, wide-ranging strike—a coup de main—will likely preclude any meaningful constraint on homeland attacks unless the initiator does clearly introduce limits in the scope of its attack.
Conclusion
In sum, preparing for the possibility of a large-scale East-West war demands that the United States and its allies move beyond outdated assumptions and embrace a clear-eyed realism about the nature of their potential adversaries. Traditional Western conceptions of thresholds in warfare are unlikely to be honored by Eastern autocratic regimes that reject these norms. Therefore, the West must reimagine how thresholds are conceptualized, communicated, and enforced—not merely through rhetoric, but through credible deterrent capabilities and a deeper understanding of the cultural and strategic worldviews of their adversaries.
The next National Defense Strategy must go further than past iterations by prioritizing warfighting readiness over peacetime optimization, returning to a resourced multi-theater war strategy, and treating the defense of the homeland as an operational theater, not an assumption. It must also confront the uncomfortable realities of war in the third nuclear age, where firebreaks are neither reliable nor symmetrical. Only through deliberate planning, accelerated force reconstitution, and hard-nosed strategic clarity can the West preserve any measure of restraint and control in what could otherwise become an unbounded and catastrophic conflict.
