Remarks by Under Secretary of War for Policy Elbridge Colby at the Naval Submarine League's Annual Symposium and Industry Update (As Prepared)

It is a true honor to be here with so many of the Silent Service. There may be no audience better suited to my message today. In the War Department under Secretary Hegseth's leadership, our approach is strong and clear but quiet. In other words, less about big talk, more about real capability. No community embodies that ethos better than yours.

The submarine force understands a basic but often neglected truth: that military power is not an abstraction. It is the product of capable people, sound strategy, technical mastery, industrial capacity, and the willingness and ability to sustain all those things over time.

Its history is distinguished, but it is not defined by ceremony or nostalgia. Instead the submarine force is defined by quiet competence, exacting professionalism, technical excellence, and a readiness to operate independently, far from support, under conditions where error is unforgiving and performance has strategic consequence. That is not merely an institutional virtue. It is a strategic asset for the United States.

Our National Security Strategy and National Defense Strategy are clear about a central fact of our time: the Indo-Pacific will be decisive to America's security, freedom, and prosperity. The United States therefore has a vital, enduring interest in maintaining a favorable balance of power in this critical region. The War Department's objective is to set the military conditions for this favorable balance-one in which no nation can dominate the United States, our allies, or the region.

That is why our defense approach centers on deterrence by denial along the First Island Chain. The logic is straightforward. We aim to ensure that a potential aggressor understands that it cannot achieve quick, decisive military success at an acceptable cost. If aggression is infeasible, escalation unattractive, and war irrational, then restraint and thus peace become the sensible course.

Denial is a realistic, not a maximalist, strategy. This is not a strategy of reckless provocation, but of strength applied deliberately and in a focused and rational way. It rests not on grand and expansive declarations, but on focused and credible capability, operational readiness, resilient posture, and the demonstrated ability to deny an adversary what it seeks at a cost the American people are prepared to accept.

If you'll permit a paean to airmen, the Battle of Britain remains one of the clearest illustrations of such a denial defense. Germany's objective was not simply to inflict damage on Britain, but to create the conditions for an invasion of the British Isles. To frustrate this, Britain did not need to conquer Germany or destroy all its forces. It needed only to deny Germany the conditions necessary to cross the Channel and sustain an effective invasion. By successfully doing so, Britain was able to make the German plan infeasible-saving Great Britain from invasion. That is the essence of denial defense: not the destruction of every part of the opposing force, but the frustration of an aggressor's theory of victory at a reasonable level of cost and risk.

Submarine forces are indispensable to such a denial defense strategy in the Indo-Pacific. In a region defined by distance and maritime geography, submarines complicate an adversary's plans in ways few other capabilities can even approach. Moreover, as the sea surface becomes more observable and more contested, the undersea domain takes on even greater strategic value.

And I can say without boasting that the United States retains an extraordinarily significant advantage undersea. Our attack submarines are without peer in their combination of stealth, endurance, sensing, and devastating effect. That advantage gives the United States a distinctive ability to operate forward, impose uncertainty, and hold at risk the capabilities on which an adversary's campaign would depend for success. No adversary considering operations at sea can prudently afford to underestimate the American undersea power. Nor do submarines act alone; rather, their effect is magnified as part of an integrated, multidomain denial strategy.

This is especially important in a conflict where geography may create a perception of asymmetric interests or resolve. The attack submarine allows the United States to generate significant operational effect without relying on a large, fixed, and vulnerable footprint. Our submarines can act far forward, even in the earliest phases of a conflict, with devastating effect, yet without risking the bulk of American military power. This is important not only militarily, but politically and strategically, enabling America to exercise major military effects at sea with relatively limited political exposure.

That is why the attack submarine has an outsized role in a credible denial defense. At a tolerable cost for America, the submarine force can pack immense striking power. This must complicate a potential adversary's calculations, constrain his freedom of action, and undermine his confidence that a military assault especially at or across the sea can achieve a quick or decisive result. It is uniquely suited to today's challenges in the Indo-Pacific region.

Now, there has been considerable attention in recent years to the limits of American military power. These discussions rightly acknowledge that the United States does not possess an unlimited ability to impose order in every contested corner of the world or operate unmolested in every domain. Our military is without peer, but it is not omnipotent.

But it is important to be precise.

Because there are domains in which the United States is unquestionably dominant - where our limits are far less constraining than in others. While I cannot get into details, friend and foe alike should note and internalize carefully that our submarines can go almost anywhere, anytime, to conduct their devastating missions, undetected. Including where they are least expected.

This capability has not been easily or quickly gained. Rather, it has been honed over the course of generations through relentless training and operating at sea, as American submariners have built up unmatched stores of professional expertise. The results are well known to this community. Again and again, our submariners have demonstrated the ability to find, follow, and strike at potential opponents' surface forces - usually without the target even realizing they have been found.

And when called upon in combat, our submariners deliver. In March, a U.S. submarine sank an Iranian frigate with a Mk-48 torpedo. It was proof of what this force is trained, equipped, and ready to do. But it was only one visible demonstration of a capability no adversary can safely presume to fully perceive, let alone counter.

In simple terms: The sea is not a place to challenge America's military might.

As a source of inspiration and example, let us recall what American submariners accomplished in the Pacific in World War II. Without our current force's benefit of almost a century of accumulated tradition and expertise, America's submariners took the fight to Japan across immense distances and imposed severe costs on Imperial Japan's position. Despite struggling with notorious problems with torpedoes and other technical and tactical challenges, and though submarines comprised less than two percent of the U.S. Navy at the time, our submariners sank more than half of Japanese merchant shipping, sending over 1,000 Japanese merchantmen and 200 warships to the bottom. American submarines daringly plunged deep into Japanese-held areas to torpedo Japan's warships and supply vessels. Even in the earlier years of the Pacific War, before America's mighty surface and air forces had helped establish sea control over the Western Pacific, American submarines crept into Japanese waters to strike without the benefit of enabling or supporting forces.

To give a sense of the disproportionate impact of our submarine force, recall the USS Tang. In one year, before her tragic loss in 1944, the Tang led by Commander Richard O'Kane sank 33 ships. In one patrol in mid-1944, Tang sank ten Japanese ships. Perhaps even more striking, well before the U.S. was even operating surface and air forces in the Western Pacific, the USS Wahoo in January 1943 sank 4 Japanese ships in the Yellow Sea. The exploits of the U.S. submarine force are well known to this audience. But they are worth recalling not only to honor their legacy and memory, but to recall what American submarines could do then - and can do now.

I need hardly tell you that today's submariners fully uphold that tradition of courage, skill, expertise, professionalism, and daring. And that record should also concentrate the mind of friend and foe on what our extraordinarily capable, modern undersea force can achieve today.

At the same time, there is no room for complacency on our part. The contemporary environment is more demanding in many respects. Potential adversaries are alert and investing heavily. We cannot assume that today's advantages will persist without deliberate effort. Our undersea advantage - while extraordinary - is not self-sustaining. Extending it requires ongoing innovation and investment in the next generation of undersea capability. The nation demands that our industry partners build on proven strengths with new approaches, new technologies, and genuine urgency.

That is why President Trump and Secretary Hegseth are calling for a generational revival of America's defense industrial base: for peace through strength. As part of this, we are calling upon the country and its representatives to make a historic $1.5 trillion infusion into our defenses and our industrial base - including for our submarine force.

For the submarine force, that means more than new construction. It means greater capacity to build, maintain, repair, and deliver undersea capability at scale. The Administration's initiatives-including a fifth naval shipyard, a new submarine-component repair center, and the recent announcement of Arsenal-2, the largest new shipyard in the United States designed to produce submarines-reflect the seriousness of that effort.

But we must translate increased industrial capacity into operational readiness. Capacity alone is not the measure of success. The decisive measures are submarines delivered on time, maintenance completed as planned, and availability improved. Industrial revitalization must result in more capable, ready forces available to the Fleet to sustain the undersea overmatch on which credible deterrence depends.

Let me close on a personal note with a simple observation: a submarine force is only as effective as those who man it. I was fortunate to grow up with the family of World War II submarine skipper James C. Dempsey, hearing of his extraordinary exploits in the Pacific. At the outset of the war, in February 1942 and in command of the World War I-era S-37, then-Lieutenant Dempsey sank the first Japanese destroyer in the Pacific, for which he was awarded the Navy Cross. Soon after, he took USS Spearfish alone into enemy controlled waters to evacuate the last Americans from Corregidor. Over the course of the war, Dempsey led ten war patrols and became one of the most distinguished submarine commanders in the Pacific War. But he was not the only one. Anyone who has visited the submarine memorial at Pearl Harbor knows the great cost suffered by our submariners to contribute so decisively to victory in the Pacific.

Dempsey's example reflects the extraordinary courage and daring but also the skill, expertise, and professionalism of that heroic group of submariners that our submariners today carry on and remain the hallmarks of this force, one of the most extraordinary elements of America's military might. It is the hard-won result of a zealously maintained and improved culture of expertise, training, professionalism, and rigor that shape every aspect of submarine training and operations. It is a culture your nation is deeply proud of, our allies rely on, and that our potential adversaries must respect, rightly fear, and have never managed to emulate.

Your nation continues to rely on your bravery, your professionalism, and your dedication - more so than for generations. Onward.

Thank you very much.