Thank you very much, Ambassador Murphy, for that generous introduction. And thank you to the faculty, students, and staff of the National War College for the opportunity to speak with you today. It is an honor to be here.
Secretary Hegseth has rightly tasked the nation's military to refocus on its core and most essential function – fighting and winning our nation's wars. This is the heart of his direction for restoring the warfighting ethos, and it carries important implications for institutions like the National War College.
In these halls, America's military officers and civilian officials have an opportunity – and indeed an obligation – to step back and think seriously about how we apply military power in defense of Americans' concrete, practical interests. Put another way: to think in rigorous and realistic terms about how to prepare for and fight our nation's wars in ways that make sense for ordinary Americans.
That responsibility has always been important. But it is probably more pressing now than at any point since the height of the Cold War, because we once again find ourselves grappling with major power rivalry under the nuclear shadow.
This has been some time coming, of course.
As President Trump's 2018 National Defense Strategy recognized, "Today, we are emerging from a period of strategic atrophy… Interstate strategic competition, not terrorism, is now the primary concern in U.S. national security." That assessment reflected underlying structural trends in the international system that were already apparent then and have only become clearer since.
For roughly a generation after the Cold War, the United States enjoyed a level of geopolitical and military predominance unprecedented in modern history. Americans became accustomed to thinking of military power as effectively unconstrained. We assumed escalation dominance and outright military superiority, and many believed achieving desired political outcomes was simply a matter of applying sufficient resolve to exercise our overwhelming military strength.
The era in which such assumptions possessed credibility has, however, passed.
The United States remains the world's strongest state. But it is also true that we now inhabit a world characterized once again by major power rivalry, real military competition, and genuine strategic constraints.
For those of you in this audience, these are not merely theoretical considerations. They are practical questions with which uniformed and civilian leaders in the Department of War must seriously grapple. Of course, it is our elected leaders who ultimately decide whether and how to apply force in defense of our nation's interests. Yet it is our collective responsibility within the Department of War to provide them with the best strategic and military counsel as they make those decisions.
That is why institutions like the National War College are so important. It is here that those entrusted with defending our nation are able to work through these problems in a rigorous fashion. As you do, it is essential to think realistically, to draw carefully on history, to dispense with shibboleths that no longer make sense, and above all to ensure that our military strategy – the way in which our nation prepares for and determines whether to wage war – keeps the costs and risks we ask Americans to bear in rational correlation to their concrete interests.
This is not as straightforward as it may have seemed twenty years ago, when the United States possessed unchallenged military predominance. Today, the defining military-strategic challenge of our era is far more difficult: How to defend important – indeed potentially very important – but nevertheless not existential interests against nuclear-armed major powers.
Addressing this problem is core to the 2026 National Defense Strategy. Within the broader defense strategy it sets out, the NDS establishes the framework for America's military strategy – the specific way the Joint Force is expected to fight a war – that the Department should adopt. But, while it defines the problem and provides a framework for that military strategy, it leaves substantial scope for the Department – and especially uniformed officers like you here – to develop and realize what exactly that entails. This is the great task I would like to inspire you and your colleagues to work on.
And solving this is no simple matter.
Under the conditions we face, our military strategy cannot sensibly be based on aspirations for total victory, unconditional surrender, or the comprehensive destruction of the opposing state.
Nor can it rest on the assumption that the balance of resolve will necessarily favor the United States. Indeed, in many plausible contingencies, the opposite may be true.
This is because, especially in conflicts fought close to the adversary's territory and far from our own, the opponent may perceive the stakes as more immediate, more proximate, and more directly connected to prestige, legitimacy, security, and political survival than Americans do.
This creates the central strategic problem our military strategy must solve:
How can the United States effectively defend critical interests against strong and resolute major power adversaries while maintaining the costs and risks for Americans at levels rationally proportionate to their interests at stake?
This criterion must be our lodestar in approaching the problem.
That is, the military strategy our nation adopts and prepares to employ must always remain correlated to the American people's interests in the issue at hand. To put it in straightforward terms, the conduct of war must not become detached from the concrete interests of the American people.
Rather, it is our obligation to ensure that the military strategy we prepare for our armed forces to put into action keeps the costs and risks of conflict in rational correlation to what Americans actually have at stake.
This is a fundamental deduction of republican government itself, reflected in the Preamble to the Constitution: that the activities of the state must fundamentally serve the common good. Asking Americans to bear costs and risks grossly disproportionate to their interests at stake in a war would violate the very logic of our republic.
To put it in another way, common sense and America First must apply not only in broad political terms, but also in the specific way our military prepares to fight and the costs and risks that way of war entails.
As President Trump's 2025 National Security Strategy puts it, "A strategy must evaluate, sort, and prioritize…The purpose of foreign policy is the protection of core national interests; that is the sole focus of this strategy." Accordingly, as the 2026 National Defense Strategy states, "this Strategy is defined by a realistic, practical approach to clearly understanding the threats Americans face and how realistically and pragmatically those threats can be addressed in ways consistent with American interests."
This approach reflects an essential strategic truth expressed succinctly by Clausewitz. He not only famously argued that war must serve political purposes, but even more importantly that "the political view must be the object, war the means, and the means must always include the object in their conception."
This insight must remain foundational for us.
Consequently, strategy cannot rationally be an abstract exercise in maximizing destruction. Nor can it be a test of national will detached from compelling political purpose.
Instead, the right strategy for our country requires the disciplined alignment of military ends, ways, and means – always retaining the political object firmly in view, not merely in terms of overall goals, but also in how the war is actually fought. In other words, strategy is not only about defining ends, but about ensuring the political object – the rational advancement of Americans' interests – is reflected also through the ways and means used by our armed forces to achieve those ends.
These considerations have always mattered. But in an era defined by major powers equipped with survivable nuclear arsenals, they become absolutely central.
In any context, if the costs and risks imposed by a strategy are grossly disproportionate to the interests at stake, that strategy is unlikely to succeed. Not only will it be unlikely to sustain Americans' support, but in any case it will not live up to the Constitution's admonition. Moreover, in the nuclear age, such an ill-suited strategy will court genuine catastrophe for our nation.
Yet let me stress that this is not an argument for passivity.
Nor can it be, if we are to defend Americans' interests properly.
This is because the United States possesses very important interests beyond mere survival. Most fundamentally, as the National Security Strategy and National Defense Strategy make clear, we have a compelling interest in preventing the emergence of concentrations of power so great that they could undermine the American way of life. As the National Security Strategy states, "The United States cannot allow any nation to become so dominant that it could threaten our interests. We will work with allies and partners to maintain global and regional balances of power to prevent the emergence of dominant adversaries."
Accordingly, we have a profound interest in maintaining favorable balances of power in the world's key regions, a point George Kennan made here at the National Defense University during his landmark lecture series at the dawn of the Cold War. And maintaining favorable balances of power requires coalitions of states sharing a common interest in preventing regional and by extension global domination.
By the same token, if the United States proves unable or unwilling to defend interests essential to sustaining such balances, then the geopolitical position upon which Americans' security, liberty, and prosperity depend will deteriorate, if not collapse.
The task of our military strategy, therefore, is to defend those interests by charting a course between passivity and recklessness. It is to calibrate the application of force, the acceptance of costs and risks, and the pursuit of compelling political objectives in a rational and proportionate way.
This may require restraint in some circumstances.
In others, however, it may require intense and sustained military action.
I stress this because I want to underline that the centrality of the political object does not mean simply a brake on military force. To the contrary, in some circumstances it may require aggressiveness and an acceptance of great risk. The point is, however, that the military approach should follow from a clear and logical conception of the political goals and tolerances.
In all circumstances, your advice – as well as your expertise and your excellence in your profession of arms – will be essential to counseling senior civilian decisionmakers as they consider these most weighty of decisions.
The essential point is to apply our disciplined and rigorous judgment in the development of a coherent military strategy aligning the use of force with the level of cost and risk Americans can reasonably sustain.
This challenge of defining such a military strategy is especially difficult because conflict between nuclear-armed powers presents a fundamentally novel problem in human history.
In earlier eras, states could aspire to total military victory because defeated powers lacked the ability to impose catastrophic consequences upon the victor.
Today, however, survivable nuclear arsenals impose profound limits on what rational states can seek to achieve through military force.
This is because even a defeated nuclear-armed major power retains the capacity to inflict devastation on the putative winner. As President Kennedy memorably warned, such a war would leave ashes in the mouth of the victor.
But let there be no misunderstanding: nuclear weapons do not eliminate war, nor the need to wage it.
They do, however, make unlimited war among major powers extraordinarily dangerous and almost inherently irrational. Very few conceivable interests justify the costs of nuclear holocaust.
As was observed early in the nuclear age, the purpose of military power increasingly became to deter and thus avert major war among nuclear-armed states rather than solely preparing to win it. Yet, at the same time, avoiding such a war requires a plausible and credible theory for how it would be fought if deterrence failed.
As President Kennedy observed, the paradox of the nuclear age is that we must guard against major war even as we manifestly and credibly prepare to fight one. As he put it in the context of the Cuban Missile Crisis, "We will not prematurely or unnecessarily risk the costs of a worldwide nuclear war in which even the fruits of victory would be ashes in our mouth – but neither shall we shrink from that risk any time it must be faced."
Accordingly, the United States must retain the ability to use force – including force at very large scale – to defend Americans' interests in the world. But we require a way to do so, including against the most formidable opponents, that limits the costs and risks to levels Americans can reasonably bear.
To borrow Henry Kissinger's formulation, our task therefore is to find a rational military strategy somewhere between surrender and suicide.
As a result, the central military-strategic question in such a context becomes not how to destroy or subjugate a nuclear-armed major power opponent, but rather how to achieve Americans' practical political objectives while maintaining costs and risks within acceptable bounds. This is the challenge of preparing for limited war under the nuclear shadow.
And our highest purpose is to deter such conflict from occurring in the first place by demonstrating both evident strength and a credible theory for employing it.
The 2026 National Defense Strategy provides a military-strategic framework for addressing this difficult problem. This framework is composed of three core elements.
The first element is denial defense – specifically, denying an opponent the ability to seize and hold the key territory of a U.S. ally or partner, thereby preventing them from acquiring the leverage necessary to subordinate that state and overturn a favorable regional balance of power, in line with the National Security Strategy's geopolitical guidance.
The second element is favorable escalation management – placing the burden of escalation, or the costs and risks of initiating escalation, on the opponent, keeping it there, and making it progressively heavier through sustained denial and selective, strategically rigorous cost imposition.
The third element is a binding strategy – structuring the conflict so that the opponent's attempts to escalate out of frustration or failure strengthen coalition cohesion, deepen allied resolve, and reinforce the balancing coalition opposing aggression.
Together, these concepts form the framework for a military strategy with which the United States can preserve favorable balances of power even under the nuclear shadow – precisely in order to prevent having to employ this strategy at all because deterrence has worked.
I will address each component in turn.
First: denial defense.
The purpose of denial is not conquest nor occupation nor the destruction of an opposing society.
It is something much more scoped, practical, and achievable: to make aggression fail.
As the National Defense Strategy states, "we will make clear that any attempt at aggression against U.S. interests will fail and is therefore not worth attempting in the first place. That is the essence of deterrence by denial."
That formulation is critically important because it focuses attention not on abstract military supremacy but on the practical frustration of aggression. As Secretary Hegseth stated in his recent posture statement, our task is "ensuring none of our allies are vulnerable to sustained, successful military aggression…This approach requires focus, prioritization, and clarity of purpose."
To be clear, this approach differs fundamentally from its principal alternatives.
On the one hand, any attempt to conquer, dominate, or subjugate a nuclear-armed major power is unlikely to succeed and would carry enormous catastrophic risks. A nuclear-armed adversary may well perceive such efforts as existential threats, and wreak the most grievous harm on Americans – for interests that are not existential for them.
On the other hand, strategies relying primarily on punishment or cost-imposition are also deeply problematic.
Such approaches often appear attractive because they promise asymmetric leverage at relatively low cost. But this is usually an illusion. In the first place, an imposition of cost does not prevent a resolute opponent from seizing territory, nor plausibly reverse it. But it can anger him, and nuclear-armed major powers possess substantial capacity to inflict pain on us as well. Thus our imposition of cost on the adversary invites him to respond by applying pain to Americans – and the more painful our application is, the more painful it is likely to be for our citizens. Moreover, even leaving aside the grievous costs such strategies are likely to entail, they are not likely to work, as competitions in pain tolerance frequently advantage the side perceiving the conflict as more vital, which is likely to be our opponent in such a struggle.
Thus a strategy relying primarily upon punishment risks imposing very high costs on Americans without providing a credible way to achieve our political objectives.
Denial defense provides a superior and credible alternative.
A denial defense focuses specifically on the military objectives necessary to achieve our political goals – no more and no less.
Operationally, this means frustrating the adversary's theory of victory, above all by denying the opponent the ability to seize and hold the key territory of a U.S. ally or partner, especially that which is material to upholding favorable regional balances of power.
This builds on the verity that most states do not willingly submit to conquest. Accordingly, partial coercive measures alone are unlikely to suffice to bring them to heel. Instead, to subordinate another state, an aggressor will generally need to seize and hold its key territory. If the attacker can seize and hold that critical land, he is likely to be capable of generating sufficiently decisive leverage over the targeted state to get it to submit.
The purpose of denial is to prevent this outcome.
I would like to stress to this audience that, importantly, denial can operationally take many forms. Invading forces may be prevented from arriving. Lodgments may be contained and reduced. Logistics and sustainment may be disrupted until any remaining foothold collapses. There is wide and ample scope for different military approaches.
What matters for the overall strategy is the effect: that aggression fails to seize and hold the targeted state's key territory, and thus fails to secure the attacker decisive political leverage.
This is no easy feat, however. While a major power adversary is unlikely to seek unlimited war, given the risks and consequences, he is more likely to pursue a rapid and limited fait accompli strategy designed to achieve gains quickly while deterring effective response by implicitly or explicitly threatening escalation.
Such strategies seek to exploit asymmetries of time, geography, and resolve. Their objective is to present the United States and its coalition with a painful dilemma: escalate at great cost and risk to reverse the aggression, or acquiesce to a changed political reality.
A denial defense is specifically designed to defeat this logic.
Moreover, if a denial defense is successful and aggression fails, the political environment itself should increasingly shift against the aggressor. States that previously hesitated to balance become more willing to do so. Allies become more resolute. And the aggressor increasingly confronts not an isolated opponent but a broadening coalition. At the same time, he can accept defeat without compromising his own genuinely core and existential interests, such as national survival.
This is why denial is so strategically powerful.
If the aggressor fails to secure his objectives, then he confronts a very difficult choice with a palatable alternative: accept tolerable failure, perhaps framed internally as some sort of success, or attempt to escalate his way out of frustration.
The burden of escalation now rests on his shoulders.
This leads directly to the second core element of the strategy: favorable escalation management.
As Thomas Schelling famously argued, strategy under the nuclear shadow involves bargaining in war – violent bargaining, certainly, but bargaining nonetheless.
In practice, of course, escalation among nuclear powers is unlikely to unfold through neat or mechanical ladders. Rather, the limits of a conflict between two such states are likely to be changeable and actually subject to direct adaptation and influence. In other words, how a war is limited is itself subject to shaping. We saw this ourselves in Korea and Vietnam, and we now see it happening in Ukraine.
Thus the material question is whether those limits and the escalation dynamics they enable improve or worsen one's political position over the course of a conflict.
Accordingly, the objective of American military strategy in the case of a conflict with a nuclear-armed major power should not be some abstract escalation dominance, which is not realistically attainable at a credible level of cost and risk in such circumstances.
Rather, our goal should be favorable escalation management: in other words, structuring the limits and dynamics of the conflict so that our efforts are enabled and advantaged, while it is the opponent who bears the heavy and unpalatable burden of deciding whether and how to escalate out of that situation.
To be clear, this must practically begin with sustained and effective denial. So long as the aggressor cannot achieve his political objectives, it is he who must choose whether to accept failure or escalate further. It is he who will bear the burden of escalation.
Conversely, if denial fails, the burden of escalation shifts onto us. We would then confront the far more dangerous position of deciding whether to accept defeat or dangerously and unfavorably escalate to reverse it. That is a position we must strive never to place American leaders in.
Yet we must also reckon with the fact that even effective denial may not by itself compel conflict termination.
This is because a strong nuclear-armed opponent may continue fighting despite lacking any plausible path to succeeding in his military aggression. He will almost certainly have the ability to do so. The question is whether he will elect to.
In such circumstances, our political leaders may decide to let the conflict simply play out, without seeking to force an end to the war. But they also may look to us to provide military options to coerce the opponent to settle or terminate the conflict – coupled, of course, with diplomatic outreach and other instruments of national power.
In this context, selective and strategically disciplined cost-imposition becomes increasingly salient.
Here Schelling's insight that "the power to hurt is bargaining power" is very relevant.
Selective cost imposition, however, must reinforce, not undermine, denial of the original objective of the aggressor. It also must remain ever-conscious of the need to avoid catastrophic escalation, especially involving nuclear weapons at scale.
Thus its purpose is not settling scores or destruction for its own sake.
Its purpose, rather, must be coercive diplomacy: persuading the opponent that continued escalation will progressively worsen his strategic position while improving neither his military prospects nor his political leverage.
This requires strategic discipline. It is here that Clausewitz' admonition to keep the political object in mind is so important: The military options in this context must advance the political goal within the plausible constraints our political leaders will set. These may be aggressive and painful or more restrained – but the options should be tailored to those political parameters.
If we can do this, even a major power nuclear-armed opponent will face the strongest set of incentives not only to conclude the conflict, but also do so in ways that limit the costs to regular Americans. This is the acme of success for our military strategy.
Finally: a binding strategy.
As Secretary Hegseth wrote in his memorandum introducing the 2026 National Defense Strategy, the era of "cloud-castle abstraction" in American foreign and defense policy has passed. Accordingly, as the National Security Strategy sets out, American strategy must instead derive from a concrete, flexible realism characterized by strategic clarity and a focus on Americans' practical interests.
This logic applies directly and materially to our alliances and coalitions.
In line with those documents, the United States is not pursuing alliances as abstractions, ends in themselves, or moral ornaments. We are sustaining, adapting, and forming them because maintaining favorable balances of power in key regions is not feasible, sustainable, or fair for Americans to shoulder alone.
Fortunately, many of our allies and partners share our same interest in favorable balances of power for their own reasons. They too seek to prevent domination of the world's key regions by nuclear-armed major powers – an interest which is, naturally, usually far more direct and concrete for them.
This alignment of interest is sturdy ground for our own geopolitical and military efforts.
Potential conflicts will largely occur near allied territory, not our own. Allies and partners possess substantial capabilities, geographic advantages, access, basing, logistical support, and increasingly capable military forces of their own. Moreover, they have an exceptionally potent interest in building up their own defense capabilities to contribute to denial defense. It is this common sense but neglected insight that has enabled so much progress over the last year with allies and partners dramatically increasing their efforts and spending on defense. The fact is that our allies can, should, and will do more for their own defense – we just had to act like it.
American strategy is accordingly focused on incentivizing, enabling, and leveraging these contributions. This is what the National Security Strategy and National Defense Strategy call for in encouraging much more effective burden-sharing with our allies and partners. This is all to the good.
At the military level, allied contributions can significantly strengthen denial while reducing the burdens placed upon our military forces, including in the context of potential simultaneity.
Moreover, our military strategy can and should specifically seek to strengthen our coalitions and their military efficacy. This is feasible because attempts at escalation by a nuclear-armed major power adversary can strengthen rather than fracture our coalition's will and cohesion.
This is the essence of a binding strategy.
The objective is to structure conditions such that aggression itself or an opponent's efforts to escalate out of frustration or failure bring additional states into closer alignment against him and deepen the resolve of those already committed.
In this way, the opponent's own escalation reinforces the balancing coalition necessary to sustain favorable regional balances of power.
Let me close by observing that the National Defense Strategy speaks of achieving a "decent peace."
That phrase is very important. It emphasizes that the purpose of American strategy is not confrontation for its own sake, nor military maximalism detached from political purpose. Our purpose is to preserve a favorable, reasonable peace in which Americans can live in security, liberty, and prosperity.
But such a decent peace does not generate itself.
It rests, rather, upon favorable balances of power, military strength, political resolve, and the credible capacity to fight and win the nation's wars. And that creates the central paradox of strategy in the nuclear age: preserving peace requires being prepared for war – but prepared for it in ways that are disciplined, proportionate, and strategically sound.
If we fail to prepare seriously, we invite aggression by convincing opponents that they might be able to use force successfully against our important interests at acceptable cost.
But if we prepare unwisely – if we adopt strategies detached from Americans' interests or that impose costs and risks on them that are grossly disproportionate to what is at stake – then we risk catastrophe.
The task, therefore, is to develop and be prepared to successfully and credibly apply a military strategy that navigates between passivity and recklessness, between suicide and surrender – a strategy of the greatest but also of disciplined strength.
Ensuring our nation is ready for this falls upon those entrusted with defending our nation. Preparing our armed forces to meet this standard will therefore depend on the expertise, judgment, and creativity of the rising generation of military and Department leaders – in other words, it depends on you and your colleagues.
Strategy is very important, but it is a framework, not a how-to guide. It will therefore fall to you to determine how to make denial work in practice; how to prepare to manage escalation under extraordinarily dangerous conditions; how to strengthen coalitions under severe pressure; and how to ensure that American military power remains firmly connected to the concrete interests of the American people.
That is a profound and grave responsibility. But it is also a noble one, in keeping with the highest traditions of our great and storied armed forces.
Thank you very much.