Prevailing in an era of comprehensive conflict

Today’s threats are complex and interconnected.¹ Only through serious, thoughtful, and regular assessment can the United States effectively understand and influence this security environment. The plasticity of this period, wherein major regions and conflicts are being fundamentally reshaped, contains challenges and opportunities for U.S. national security interests.           

Understanding global threats

For most of the second half of the twentieth century, American strategic planners largely faced a Cold War in which superpower conflict was kept on ice by nuclear deterrence, turning hot in proxy fights that were costly but containable. The collapse of the Soviet Union brought that era to an end. In Washington during the 1990s, war became a matter of assembling coalitions to intervene in discrete conflicts when bad actors invaded their neighbors, stoked civil or ethnic violence, or massacred civilians. After the shock of the 9/11 attacks in 2001, U.S. strategy shifted to terrorist organizations, insurgents, and other nonstate groups. The resulting “war on terror” pushed thinking about state-on-state conflict to the sidelines. For most of this century, the prospect of a major war among states was a lower priority for American military thinkers and planners, and whenever it took center stage, the context was usually a potential conflict with China that would materialize only in the far-off future, if ever.

Now, the relatively narrow scope that defined war during the post-9/11 era has dramatically widened. An era of limited war has ended; an age of comprehensive conflict has begun. What the world is witnessing today is akin to what theorists in the past called “total war,” in which combatants draw on vast arrays of resources, mobilize their societies, attack a broad variety of targets, and reshape their economies to prioritize warfare over all other state activities.

The character of war is changing in three fundamental ways:

1. The continuum of conflict has collapsed

In an earlier era, one might have seen the terrorism and insurgency of Hamas, Hezbollah, and the Houthis as inhabiting the low end of a spectrum of conflict intensity; the armies waging conventional warfare in Ukraine as residing in the middle; and the nuclear threats shaping Russia’s war and China’s growing arsenal as sitting at the high end. Today, however, there is no sense of mutual exclusivity between these domains; the continuum of conflict has collapsed. To put it in cinematic terms, when it comes to war, we see “everything, everywhere, all at once.” In Ukraine, “robot dogs” patrol the ground and autonomous drones launch missiles from the sky amid trench warfare that looks like World War I—all under the specter of nuclear weapons. In the Middle East, combatants combined sophisticated air and missile defense systems with individual shooting attacks by armed men riding motorcycles. In the Indo-Pacific, Chinese and Philippine forces face off over a single dilapidated ship while the skies and seas surrounding Taiwan get squeezed by threatening maneuvers from China’s air force and navy.

The prominence of sea-based struggles, in particular, marks a major departure from the post-9/11 era, when conflict was largely fought on land. Back then, most maritime attacks were sea-to-ground, and most air attacks were air-to-ground. Today, the maritime domain has become a major site of direct conflict. Ukraine has taken out more than 20 Russian ships in the Black Sea, and control of that critical waterway remains contested. Meanwhile, Houthi attacks largely closed the Red Sea to commercial shipping.

The multidimensional character of conflict also underscores the risk of being tempted by today’s weapon of choice, which might turn out to be a flash in the pan. Compared with the post-9/11 era, more countries now have greater access to cheaper materials and more research and development (R&D) capacity, allowing them to respond more quickly and adeptly to new weapons and technologies by developing countermeasures. This exacerbates a familiar dynamic that the military scholar J. F. C. Fuller described as “the constant tactical factor”—the reality that “every improvement in weapons has eventually been met by a counter-improvement which has rendered the improvement obsolete.”

2. The demography of war has expanded

The cast of characters shaping war has become increasingly diverse. The post-9/11 wars were defined by the outsize impact of terrorist groups, proxies, and militias. As those conflicts ground on, many policymakers wished they could go back to the traditional focus on state militaries—particularly given the enormous investments some states were making in their defenses. They should have been careful what they wished for: state militaries are back, but nonstate groups hardly left the stage. The current security environment offers the misfortune of dealing with both.

In the Middle East, multiple state militaries are increasingly fighting or enmeshed with surprisingly influential nonstate actors. The Houthis are responsible for the most intense set of sea engagements the U.S. Navy has faced since World War II and their attacks have negatively impacted the global economy. With help from Iran, the Houthis are also punching above their weight in the air by manufacturing and deploying their own drones. Meanwhile, in Ukraine, Kyiv’s regular forces are fighting alongside cadres of international volunteers in numbers likely not seen since the Spanish Civil War. And to augment Russia’s traditional forces, the Kremlin has incorporated mercenaries from the Wagner paramilitary company and sent tens of thousands of convicts to war—a practice Ukraine’s military copied.

In this environment, the task of building partner forces becomes even more complex than during the post-9/11 wars. U.S. programs to build the Afghan and Iraqi militaries focused on countering terrorist and insurgent threats with the aim of enabling friendly regimes to exert sovereignty over their territories. To help build up Ukraine’s forces for their fight against another state military, however, the United States and its allies have had to relearn how to teach. The U.S. Department of Defense built a new kind of coalition, convening more than 50 countries from across the world to coordinate materiel donations to Ukraine through the Ukraine Defense Contact Group—the most complex and most rapid effort ever undertaken to stand up a single country’s military.

Although the United States had been building militaries in fragile states since World War II, its record was lackluster. That is no longer the case. The Pentagon’s new system has demonstrated that it can move so quickly that materiel support for Ukraine has at times been delivered within days. The system has surged in ways that many thought impossible. In particular, the technical aspect of equipping militaries has improved. For example, the U.S. Army’s use of artificial intelligence has made it much easier for Ukraine’s military to be able to see and understand the battlefield, make decisions, and act accordingly. Lessons from the rapid delivery of assistance to Ukraine have also been applied to the Israel-Hamas war; within days of the attacks on October 7, 2023, U.S.-supplied air defense capabilities and munitions were in Israel to protect its skies and help it respond. Overall, the technical aspects of providing support to foreign militaries have been streamlined so that the system now consistently works in ways it did not before—particularly in terms of speed.

But even though Washington has demonstrated that it can build a foreign military with alacrity, the question will always remain as to whether it should. The cost of transferring valuable equipment to a partner involves considerations of the U.S. military’s own readiness levels and combat credibility. Moreover, such assistance is not merely a technical effort but a political exercise as well, and the system has occasionally slowed down as it wrestles with dilemmas regarding the full implications of U.S. security aid. For example, to avoid tripping Russia’s red lines, Washington has spent enormous time debating where, when, and under what circumstances Ukraine should use U.S. military assistance. This puzzle is not new, but given the destructive abilities of the rivals that Washington is now facing or preparing to confront, the stakes of solving it correctly are much higher than during the post-9/11 era.

The role of defense industrial bases in rival countries has also shaped the new contours of war-making. In the dozens of countries supporting Ukraine, domestic defense industries have not been able to keep up with the demand. Meanwhile, Russia’s defense industrial base has been revived after speculations about its demise proved to be greatly exaggerated. Although China’s support to Russia appears to exclude lethal assistance, it has nevertheless involved Beijing providing Moscow with critical technologies, representing a stronger partnership. And both Iran and North Korea support their defense industries by selling munitions and other wares to Moscow. The United States is not the only power to recognize the value (both on the battlefield and back home) of supplying partner forces and building up their capacities; its adversaries have, as well. 

3. The return of deterrence

During the two decades of the post-9/11 era, the concept of deterrence was rarely invoked in Washington since the idea seemed largely irrelevant to conflicts against nihilistic nonstate actors such as al-Qaida and ISIS. What a difference a few years make: Today, almost every debate about U.S. foreign policy and national security boils down to the challenge of deterrence. This change in conversation is because the global threat environment has evolved such that states like China now pose the biggest threat to U.S. national security interests.

In this new environment, traditional approaches to deterrence are regaining relevance. One is deterrence by denial—the act of making it difficult for an enemy to achieve its intended objective. Denial can quell escalation even if it fails to prevent an initial act of aggression. In the Middle East, Israel was unable to stop Iran’s major conventional attacks on Israeli territory, but it largely denied Iran the benefits it hoped to gain. Israel’s military repulsed almost all of the Iranian missiles and drones thanks to its sophisticated air and missile defense systems and the collaboration of the United States and countries across the Middle East and Europe. (Shoddy Iranian equipment also played a role.) The limited repercussions of the attack enabled Israel to wait to respond and to do so in more limited ways than would have been likely had Iran’s operations been more successful. But the wins were costly: the United States and Israel may have spent 10 times more in responding to Iran’s April 2024 attack than Iran did in launching it.

Another traditional means of deterrence that resurfaced is punishment, which requires credibly threatening an adversary with severe consequences if it takes certain actions. At a few key junctures, Vladimir Putin’s saber-rattling brought the risk of nuclear weapons use to its highest point since the Cold War. During one fraught period in October 2022, experts worried there was a 50% chance that Putin would employ his nuclear arsenal. In calls with Russian counterparts, senior American leaders made stern and timely warnings of “catastrophic” consequences if Moscow made good on its threats. Those warnings worked, as did a broader effort to persuade key Indo-Pacific and European countries, most notably China and India, to publicly and prospectively condemn any role for nuclear weapons in Ukraine. Tugging Putin down the escalation ladder required a baseline understanding of how he viewed threats, serious attention to the signals and noise being sent across the entire U.S. government, and active feedback loops to ensure those assessments were accurate—all paired with robust diplomatic engagements.

A third approach to deterrence is through resilience, which the 2022 U.S. National Defense Strategy (NDS) described as “the ability to withstand, fight through, and recover quickly from disruption.” Resilience is the ration­ale behind the historic and ongoing dispersal of U.S. military bases in the Indo-Pacific, which will allow American forces to absorb an attack and continue fighting. The presence of increasingly capable dispersed U.S. military assets (alongside those of allied and partner militaries) complicates Chinese planning by creating potential pathways to preclude Chinese efforts to overturn the status quo, increases the complexity of those contingencies, and induces uncertainty about which may be the most relevant. It’s true that it will be difficult to know whether any particular U.S. ally or partner will prove willing to use or allow the use of military assets from its territory in a conflict. But that uncertainty is a feature, not a bug, of this approach. Simply put, although the United States may not have full clarity about what role specific allies and partners will play should a conflict erupt, neither does China. 

Tackling global threats

To best protect U.S. national security interests amid the most turbulent global security environment in decades, the United States should focus on:

Prioritizing China but not ignoring other threats 

No other country has the will, and increasingly the capability, to fundamentally reshape the global security order—a global security order that has benefited U.S. national security interests for 80 years. The tricky strategic question isn’t whether the United States should prioritize the threat posed by China—the answer to that is undoubtedly yes—but instead, how and in what ways to best address other major threats, including Russia, North Korea, Iran, and terrorism. Increasingly, this presents less of a binary choice than previously given the increasing cooperation between and among adversaries. That offers opportunities—such as both Russia and Iran losing strategic ground with the fall of Syrian President Bashar al-Assad—but also challenges, as demonstrated by Iranian and North Korean military support to Russia. And of course, there is a ceiling and limits to these relationships among U.S. adversaries. The United States has finite resources, including time, attention, and capabilities, and must take that into account when juggling security challenges; but ignoring threats is shortsighted and nonstrategic. Put simply, the United States cannot do it all nor is it some middling power that can only focus on one issue.

The United States should smartly apply its resources to those other threats in a sustainable manner. For example, 2024 was the most dynamic year for the Middle East since 1979, which thrust Iran into its most vulnerable position in nearly 50 years. This weakness provides a crucial opportunity to establish criteria for serious negotiations on its nuclear program. Outside of the Middle East, the terrorist threat has metastasized, particularly across the Horn of Africa and broader West Africa. Tackling it requires continuing to work with partner militaries and civilian institutions. And in Europe, where Russia’s military has suffered 700,000 casualties without any American servicemembers engaged in direct fighting, support to Ukraine’s institutions has had a massive impact on a rogue actor seeking to upend the security environment. In these examples, and in many more, the United States should work with other countries and use all its tools of statecraft to press advantages so that it can focus on China.

Strengthening America’s military and other tools of statecraft

The United States must be able to deter threats and, if that fails, to prevail in war. That requires a lethal, resilient, sustainable, and agile military; one that can effectively balance between responding to today’s threats while maintaining the capability to counter tomorrow’s threats. It must take a strategy-driven and resource-informed approach when doing so.

Today, the defense budget is both at the highest level in U.S. history and a historically low level as a percentage of GDP (approximately 3%, which is around the same as the mid-1990s). However, it is more important to focus on what should and should not be funded rather than a single top-line number. Overall, the military must continue modernizing and more quickly integrating and fielding capabilities, particularly by incentivizing innovation to increase in pace and scale. Investments should include nuclear modernization (particularly given the unprecedented nuclear threat environment); undersea platforms; uncrewed systems across domains; resilient space architecture; cyber; artificial intelligence; munitions (a traditionally orphan issue where congressional leadership has been particularly crucial); the submarine industrial base; and R&D. Creating a focused “deterrence fund” to support operations, posture, readiness, and security cooperation in the Indo-Pacific, for example, would make it easier to target resources related to the pacing challenge of China. Big bet investments strengthen the U.S. defense industrial base, invest in the American workforce, and ensure American technological competitive edge in critical areas to hopefully deter conflict and prevail in war if it erupts.

Even with more funding, the military requires cuts to maintain its strategic focus and evolve in line with the security environment. Those include relooking excess infrastructure—particularly since it has been almost two decades since the last serious effort to close bases—older ships and aircraft (including A-10s and littoral combat ships), and compensation costs, including personnel and benefits. And as this committee knows well, the Department of Defense (DOD) has gone nearly a decade and a half without on-time appropriations. Continuing resolutions make it very difficult to realize strategy; they are an “own goal” that weakens the U.S. military.

Beyond resources and platforms, there are two key areas of DOD to reexamine. First, talent management. It is often said that the people who serve are our military’s greatest asset. That is indeed true; at its core, our military prowess is an extension of its servicemembers’ capabilities.  As the security environment grows more complex, having a force whose members have varied backgrounds and experiences is a strategic and warfighting advantage vis-à-vis adversaries like China and Russia. Second, organizational structures in DOD are unwieldy. Relooking the increasingly sprawling structures, including consolidating combatant commands and military department components, can better align DOD’s objectives and resources.

This committee has a crucial role to play in ensuring DOD is tracking, assessing, and enabling the United States to navigate and thrive in this dynamic security environment. Indeed, the secretary of defense is required to give Congress an update this month assessing the National Defense Strategy. Having led the last NDS and contributed to many others, I recommend the committee ask hard questions about risk—including risk to strategy and risk to force—and seek mitigation; push for assessments on the wars in Europe and the Middle East; request an update on threats to deterrence in the Indo-Pacific; and seek details regarding the use of U.S. troops on the border, the impact on the military’s ability to prioritize China, and broader administration plans to empower the Department of Homeland Security to fulfill its statutory obligations rather than relying on the U.S. military to do so.

But relying solely on the U.S. military to address global threats is a recipe for disaster. The United States has historically had several tools in its statecraft toolkit, including diplomacy, development, and economic carrots and sticks. Dismissing, under-funding, or degrading U.S. soft power means the United States will rely on hard power. Ultimately, that approach is not only inefficient, but it will cost more—in American treasure and American lives. The military is often not the most appropriate tool or fit for purpose. Indeed, during the post-9/11 wars, the military was at times used in ways that did not play to its competitive advantages. Moreover, there is an opportunity cost inherent in using the military in nonstrategic ways; it is unable to focus and prioritize and can lose readiness. That means the military takes its eyes off the most serious threats and at a minimum, cedes the playing field to adversaries like China and Russia; at a maximum, it means the military does not have the capabilities or the readiness to address those threats.

Collaborating with allies and partners

America’s unparalleled network of allies and partners sets it apart from every other great power in history. When international challenges or opportunities arise, many countries turn to the United States to share their assessments and to collaboratively plan the way forward. Today, many U.S. allies and partners across Europe and the Indo-Pacific are turbocharging their defense budgets. Sustaining these investments will be critical given the multiple and varied threats ahead. U.S. diplomacy has brought countries within the Indo-Pacific together and created connections between regions. The former is illustrated by the historic U.S.-brokered progress between Japan and South Korea and by the Quad (composed of the United States, India, Australia, and Japan). The latter is represented by the creation of AUKUS (a major military partnership joining Australia, the United Kingdom, and the United States), and by the inclusion of four of America’s Indo-Pacific allies in the last three NATO summits. These tighter relationships are a net positive, and increasing the size, scope, and scale of collaboration is a crucial deterrent and an asset. More broadly, working by, with, and through allies and partners to tackle global threats—those of today and tomorrow—is ultimately more effective and less pricey.

In conclusion, for the United States to prevail in an era of comprehensive conflict requires a sense of urgency and vigilance and, above all, a wide aperture about how threats are evolving—and what we must do to effectively respond to them.