Introduction

For much of the preceding century, American power has preserved our liberty and served as the principal deterrent to aggression. Our historic economic power has financed a military that has served as the shield under which the tools of diplomacy, trade, and engagement have produced unprecedented progress and peace. After decades of neglect, however, the shield is cracking. America’s global influence is being surrendered and reversed, threatening global peace and stability, and our homeland is no longer immune from external threat.

The United States maintains a military force primarily to protect the homeland from attack and to protect its interests abroad. Other uses—assisting civil authorities in times of emergency, for example, and maintaining the perception of combat effectiveness to deter enemies—amplify other elements of national power such as diplomacy or economic initiatives, but America’s armed forces exist above all else so that the U.S. can physically impose its will on enemies and change the conditions of a threatening situation by force or the threat of force.

The Heritage Foundation’s Index of U.S. Military Strength gauges the ability of America’s military to perform its missions in 2023 and assesses how the military’s condition has changed during the preceding year. The Index is not meant either to predict what the U.S. military might be able to do in the future or to accord it efficacy today based on the promise of new technologies that are in development rather than fielded and proven in use. It is a report to American citizens on the status of the military that they join, that they support, and on which they depend.

The United States prefers to lead through “soft” elements of national power—diplomacy, economic incentives, and cultural exchanges—but soft power cannot ultimately substitute for raw military power. When soft approaches such as diplomacy work, their success often owes much to the knowledge of all involved that U.S. “hard power” stands ready, however silently, in the background. In similar fashion, countries seek an economic relationship with the United States because of the strength of the U.S. economy and the country’s perceived long-term viability and stability. All are predicated on America’s ability to protect itself, safeguard its interests, and render assistance to its allies—all of which depends on a competent, effective, and commensurately sized military. As Frederick the Great (1712–1786) observed, “Diplomacy without arms is like music without instruments.”

Soft approaches cost less in manpower and treasure than military action costs and do not carry the same risk of damage and loss of life, but when the United States is confronted by physical threats to its national security interests, it is the hard power of its military that carries the day. In fact, the absence of military power or the perception that hard power is insufficient to protect critical interests will frequently—and predictably—invite challenges that soft power simply cannot address. Thus, hard power and soft power are complementary and mutually reinforcing. An insufficiency of either damages the other and ultimately jeopardizes the country’s future.

The decline of America’s military hard power, historically shown to be critical to defending against major military powers and to sustaining operations over time against lesser powers or in multiple instances simultaneously, is thoroughly documented and quantified in this Index. It is harder to quantify the growing threats to the U.S. and its allies that are engendered by the perception of American weakness abroad and doubts about America’s resolve to act when its interests are threatened.

The anecdotal evidence is consistent with direct engagements between Heritage scholars and high-level diplomatic and military officials from countries around the world: The aging and shrinking of America’s military forces, their reduced presence in key regions since the end of the Cold War, and various distractions created by America’s domestic debates have created a perception of American weakness that contributes to destabilization in many parts of the world, prompts old friends to question their reliance on America’s assurances, and spurs them to expand their own portfolio of military capabilities or to seek other alliances with stronger partners.

While strong allies with close ties to America are a boon for U.S. security and prosperity, partners that are less well integrated into the U.S. security umbrella reflect the decline of U.S. influence in regional affairs. Policy decisions made by Saudi Arabia and Turkey over the past year or two, for example, to strengthen economic, military, and diplomatic ties with China and Russia, respectively, serve to illustrate this reality. Countries will take steps to secure their interests, regardless of U.S. desires, if they perceive that relations with powers other than the U.S. best serve those interests. For decades, the perception of American strength and resolve has helped to deter adventurous bad actors and tyrannical dictators and has supported a global network of U.S. allies and partners. Regrettably, both that perception and, as a consequence, its deterrent and reassuring effects are eroding.

Recognition of this problem is growing in the U.S. and was forcefully addressed in the 2018 National Defense Strategy (NDS),1 which called for a renewal of America’s military power. However, spending on defense must be commensurate with the interests that the military is called upon to protect, and there continues to be a significant—even growing—gap between the two.

The current NDS, released in March 2022,2 did little to allay concerns about this gap or to provide any meaningful detail on how the Department of Defense (DOD) would focus its energies to close the gap by setting goals, establishing and implementing strategies, or modifying its forces so that defense budget requests included a compelling rationale. Further, a bipartisan compromise3 to eliminate the national debt ceiling through January 1, 2025, provided for a 3.3 percent increase in defense spending for fiscal year (FY) 2024 and a mere 1 percent increase for FY 2025 while inflation hovers around 6 percent, effectively reducing the military’s ability to make any progress in modernization, capacity, or readiness. Meanwhile, America’s allies, with a few notable exceptions, continue to underinvest in their military forces, and the United States’ chief competitors are hard at work improving their own.

An Increasingly Dangerous World

The result is an increasingly dangerous world threatening a weaker America. This might seem odd to many observers because U.S. forces have dominated the battlefield in tactical engagements with enemy forces over the past 30 years. Not surprisingly, the forces built to battle those of the Soviet Union have handily defeated the forces of Third World dictators and terrorist organizations. These military successes, however, are quite different from lasting political successes and have masked the deteriorating condition of America’s military, which has been able to undertake such operations only by “cashing in” on investments made in the 1980s and 1990s.

Unseen by the American public, the consumption of our military readiness has not been matched by corresponding investments in replacements for the equipment, resources, and capacity used up since September 11, 2001, in places such as Iraq, Afghanistan, and Syria. As of late July 2023, U.S. support for Ukraine had consumed an additional $44 billion of military equipment and ammunition4 taken directly from existing stores, reducing the resources that would be available to U.S. forces in the event of another conflict and making it necessary to replenish them in the future.

It is therefore critical that we understand the condition of the United States military with respect to America’s vital national security interests, the threats to those interests, and the context within which the U.S. might have to use hard power. It is likewise critically important to grasp how these three areas—operating environments, threats, and the posture of the U.S. military—change over time, given that such changes can have substantial implications for defense policies and investments.

The U.S. Constitution opens with a beautiful passage in which “We the People” state that among their handful of purposes in establishing that Constitution was to “provide for the common defence.” The Constitution’s enumeration of limited powers for the federal government includes both the powers of Congress “To declare War,” “To raise and support Armies,” “To provide and maintain a Navy,” “To provide for calling forth the Militia,” and “To provide for organizing, arming, and disciplining, the Militia” and the power of the President as “Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States.”

With such constitutional priority given to defense of the nation and its vital interests, one might expect the federal government to produce a standardized, consistent reference work on the state of the nation’s security. Yet no such single volume exists, especially in the public domain, to allow comparisons from year to year. In the past half-dozen years, the DOD has moved to restrict reporting of force readiness even further. Thus, the American people and even the government itself are prevented from understanding whether investments in defense are achieving their desired results.

What America needs is a publicly accessible reference document that uses a consistent, methodical, and repeatable approach to assessing defense requirements and capabilities. The Heritage Foundation’s Index of U.S. Military Strength, an annual assessment of the state of America’s hard power, fills this void, addressing both the geographical and functional environments that are relevant to our vital national interests and the threats that rise to a level that puts or has the strong potential to put those interests at risk.

Any assessment of the adequacy of military power requires two primary reference points: a clear statement of U.S. vital security interests and an objective requirement for the military’s capacity for operations that serves as a benchmark against which to measure current capacity. Top-level national security documents issued by a long string of presidential Administrations have consistently made clear that three interests are central to any assessment of national military power:

• Defense of the homeland;
• Successful conclusion of a major war that has the potential to destabilize a region of critical interest to the U.S.; and
• Preservation of freedom of movement within the global commons: the sea, air, outer space, and cyberspace domains through which Americans conduct their business.

Every President has recognized that protecting America from attack is one of the U.S. military’s fundamental reasons for being. Going to war has always been controversial, but the decision to do so has been based consistently on the conclusion that not going to war would leave the country more vulnerable to attack.

This Index embraces the requirement that the U.S. military should be able to handle two major wars or two major regional contingencies (MRCs) successfully at the same time or in closely overlapping time frames as the most compelling rationale for sizing U.S. military forces. The new cold war with China5 in which we find ourselves requires a force construct preserved until the close of the last one. The basic argument is this: The nation should have the ability to engage and defeat one opponent and still have the ability to prevent another opponent from exploiting the perceived opportunity to move against U.S. interests while America is engaged elsewhere. It is also vital to retain flexibility, because no attribute is applied in war more universally than uncertainty is.

The Index is descriptive, not prescriptive: It reviews the current condition of its subjects within the assessed year and describes how conditions have changed from the previous year, informed by the baseline condition established by the inaugural 2015 Index.6 In short, the Index answers the question, “Have conditions improved or worsened during the assessed year?”

This study also assesses the U.S. military against the two-war benchmark and various metrics that are explained further in the military capabilities section. Importantly, the Index measures the hard power needed to win conventional wars rather than the general utility of the military relative to the breadth of tasks it might be (and usually is) assigned to perform in order to advance U.S. interests short of war.

The authors recognize that advances in technology can translate into new military capabilities, but technology should not be seen as a panacea for all that ails the U.S. military. New tools, platforms, and weapons prompt some observers to assume that older capabilities can be replaced easily by new ones, often in reduced numbers, or that the current force will inevitably be transformed in ways that make it decisively better than that of an opponent. Typically missing in these optimistic assessments of what the future military might then be able to do is a corresponding recognition that competitors quickly adopt similar technological advances in their own militaries or that the new capability might not be as effective as we believed it would be during its development.

The current war in Ukraine offers compelling evidence of this. Although new technologies—unmanned aerial vehicles, anti-armor guided munitions, cyberwarfare—are on display in abundance, “old school” weaponry such as artillery, rockets, and automatic weapons has proven to be devastatingly effective. The war also serves as a reminder that capacity in people, equipment, munitions, and various supplies is essential to sustained operations, as is the ability to rapidly reconstitute losses. And the savage Iranian-sponsored October 7, 2023, Hamas terrorist attack on Israel demonstrates that even one of the world’s most high-tech countries can be vulnerable to low-tech methods such as paragliders, tunnels, and written communications that evade electronic surveillance.

The historical record of war shows repeatedly that new technologies convey temporary advantages: The force that wins is usually the one that is best able to sustain operations over time, replace combat losses with fresh forces and equipment, and use its capabilities in novel ways that account for the enemy, terrain, time, and achievable objectives. This reality has led the authors to return consistently to an appreciation of the force’s capacity, the modernity of its capabilities, and its readiness for close combat with an equally capable and competent enemy. Consequently, this Index continues to emphasize the importance of the two-war force sizing benchmark and the need to ensure that the current force is ready for war and materially capable of winning in hard combat in real rather than imagined worlds.

Assessing the World and the Need for Hard Power

The assessment portion of the Index is composed of three major sections that address the aforementioned areas of primary interest: the operating environments within or through which America’s military must be employed, threats to U.S. vital national interests, and the U.S. military services themselves. For each of these areas, the Index provides context by explaining why a given topic is addressed and how it relates to understanding the nature of America’s hard-power requirements.

The authors of this study used a five-category scoring system that ranges from “very poor” to “excellent” or “very weak” to “very strong” as appropriate to each topic. This approach is the best way to capture meaningful gradations while avoiding the appearance that a high level of precision is possible given the nature of the issues and the information that is publicly available.

Some factors are quantitative and lend themselves to discrete measurement. Others are inherently qualitative in nature and can be assessed only through an informed understanding of the material that leads to an informed judgment.

By themselves, purely quantitative measures tell only part of the story when it comes to hard power’s relevance, utility, and effectiveness. Using only quantitative metrics to assess military power or the nature of an operating environment can lead to misinformed conclusions. For example, the mere existence of a large fleet of very modern tanks has little to do with the effectiveness of the armored force in actual battle if the employment concept is irrelevant to modern armored warfare. (Imagine, for example, a battle in rugged mountains.) Also, experience and demonstrated proficiency are often so decisive in war that numerically smaller or qualitatively inferior but well-trained and experienced forces can defeat a larger or qualitatively superior adversary that is inept or poorly led. Again, the differing performance of Russian and Ukrainian troops is illuminating, and countries like China are taking note.

The world is still very much a qualitative place, however digital and quantitative it might appear to have become thanks to the explosion of advanced technologies, and judgments have to be made in the absence of certainty. We strive to be as objective and evenhanded as possible in our approach and as transparent as possible in our methodology and sources of information so that readers can understand why we reach the conclusions we reach—and perhaps reach their own as well. The result will be a more informed debate about what the United States needs in terms of military capabilities to deal with the world as it is. A detailed discussion of scoring is provided in each assessment section.

In our assessment, we begin with the operating environment because it provides the geostrategic stage upon which the U.S. attends to its interests:

• The various states that would play significant roles in any regional contingency;
• The terrain that enables or restricts military operations;
• The infrastructure—ports, airfields, roads, and rail networks (or lack thereof)—on which U.S. forces would depend; and
• The types of its linkages and relationships with a region and major actors within it that cause the U.S. to have interests in the area or that facilitate effective operations.

Major actors within each region are identified, described, and assessed in terms of alliances, political stability, the presence of U.S. military forces and relationships, and the maturity of critical infrastructure.

Our assessment focuses on three key regions—Europe, the Middle East, and Asia—because of their importance relative to U.S. vital security, economic, and diplomatic interests. This does not mean that we view Latin America and Africa as unimportant. It means only that currently, the security challenges within these regions do not directly threaten America’s vital interests as we have defined them. We addressed their condition in the 2015 Index7 and will provide updated assessments when circumstances make such reassessments necessary.

Next comes a discussion of threats to U.S. vital interests. Here we identify the countries and non-state actors that are the greatest current or potential threats to U.S. vital interests based on two overarching factors: behavior and capability. We accept the classic definition of “threat” as a combination of intent and capability, but while capability has attributes that can be quantified, intent is difficult to measure. We concluded that “observed behavior” serves as a reasonable surrogate for intent because it is the clearest manifestation of intent.

We based our selection of threat countries and non-state actors on their historical behavior and explicit policies or formal statements vis-à-vis U.S. interests, scoring them in two areas: the degree of provocative behavior that they exhibited during the year and their ability to pose a credible threat to U.S. interests regardless of intent. For example, a state full of bluster but with only a moderate ability to act accordingly poses a lesser threat, and a state with great capabilities and a record of bellicose behavior that is opposed to U.S. interests warrants attention even if it is relatively quiet in a given year. The combination of behavior and ability to pose a credible threat eliminates most smaller terrorist, insurgent, and criminal groups and many problematic states because they do not have the ability to challenge America’s vital national interests successfully.

Finally, we address the status of U.S. military power in three areas: capability (or modernity), capacity, and readiness. To do this, we must answer three questions:

• Do U.S. forces possess operational capabilities that are relevant to modern warfare?
• Do they have a sufficient quantity of such capabilities?
• Is the force sufficiently trained to win in combat, and is its equipment materially ready?

Presumably, if the answer to all three questions is “yes,” the U.S. military would be able to defeat the military force of an opposing country.

All of these are fundamental to success even if they are not de facto determinants of success. Turning again to the Russia–Ukraine War for an illustrative example, Russia’s advantages in capacity, modernity, and assumed readiness (as was likely reported by Russian commanders to their national leadership) have not translated into the victory expected by Moscow, but it is likely safe to assume that Russian President Vladmir Putin would not have embarked on the war without such advantages. Ukraine would certainly not have withstood the assault as well as it has without support from other countries that made up for deficiencies in these same areas.

We also address the condition of the U.S. nuclear weapons capability, assessing it in areas that are unique to this military component and critical to understanding its real-world viability and effectiveness as a strategic deterrent, and provide a descriptive overview of current U.S. missile defense capabilities and challenges.

However, the Index does not assess (score) U.S. cyber and missile defense capabilities. There are as yet no viable metrics by which to measure the capacity, capability, or readiness of these elements of national defense, their constituent service components, and elements of the government that contribute to activities in these domains, and it is not yet clear how one would assess their roles in measuring “hard combat power,” which is the focus of this publication. A thorough assessment will have to be part of a future Index. However, we do provide overviews of each functional capability, explaining to the reader the capability as it is currently constituted and aspects of its function and contribution.

Topical Essays

Each edition of the Index provides the opportunity to share with readers authoritative insights into issues that affect U.S. military power. Past editions have included essays on logistics, alliances, experimentation, the spectrum of conflict and the domains in which forces operate, and special operations forces, among many other subjects. There is a lot of shaft that makes the pointed end of a spear effective, and we endeavor to explain what this means with these essays.

In this edition, we are pleased to share the work of authors who address various trends related to the ability of the United States to defend itself and its interests.

• The Heritage Foundation has been producing the Index of U.S. Military Strength for a decade, this edition being the tenth. What insights do 10 years of assessments generate regarding the status of U.S. military power, the ability of allies to contribute to mutually beneficial security matters, and the evolution of threats as they relate to such interests? The originator and editor of the Index, Dakota Wood, takes a stab at drawing such insights from the work of a great number of contributors in his essay, “The Index of U.S. Military Strength: Ten Years in Review.”
• Dr. James Carafano reminds us of the U.S. military’s history in rallying to the cause of national defense and how its composition and contributions to America as well as its actions serve much more than purely physical security interests. His essay, “The Role of the Military in U.S. History: Past, Present, and Future,” is a must-read reminder of just how intertwined America’s military is with the strength of the country not just in military power, but also in stability and the health of its economy, political system, and cultural life.
• Dr. Anna Simons contributes a compelling story from the other side of the civil–military relationship. In “The Military and Society: A Refresher,” she addresses societal, cultural, and popular attitudinal matters from a very personal point of view. As a long-practicing social anthropologist who has worked with the military community for decades, especially the special operations community, Dr. Simons shares her considerable insights into societal factors that affect and are affected by the U.S. military.
• The ongoing war in Ukraine serves as a painful reminder of war’s ravenous appetite for equipment and ammunition (in addition to the terrible toll it takes in human lives) as defenders and aggressors churn through their inventories of each in often-desperate attempts to achieve their objectives. Maiya Clark, in “The U.S. Defense Industrial Base: Past Strength, Current Challenges, and Needed Change” provides a brief history of America’s defense industrial base and then examines vulnerabilities, risks, and attendant matters of procurement and acquisition as they relate to America’s ability to produce the material needed for defense.
• Intimately related to defense production are the willingness, ability, and need to invest in military power, a topic Frederico Bartels embraces in “Understanding the Defense Budget.” There has always been an ebb and flow in funding for defense; it increases when dangers clearly threaten and falls off when peace reigns, especially the farther one gets from a time of conflict. When debates over defense spending occur, they often take place without any real understanding of what the defense budget is. Bartels provides an excellent primer.

Scoring U.S. Military Strength Relative to Vital National Interests

The purpose of this Index is to make the national debate about defense capabilities better informed by assessing the U.S. military’s ability to defend against current threats to U.S. vital national interests within the context of the world as it is. Each of the elements considered—the stability of regions and access to them by America’s military forces; the various threats as they improve or lose capabilities and change their behavior; and America’s armed forces themselves as they adjust to evolving fiscal realities and attempt to balance readiness, capacity (size and quantity), and capability (how modern they are) in ways that enable them to carry out their assigned missions successfully—can change from year to year.

Each region of the world has its own set of characteristics that include terrain; man-made infrastructure (roads, rail lines, ports, airfields, power grids, etc.); and states with which the United States has relationships. In each case, these factors combine to create an environment that is either favorable or problematic when it comes to the ability of U.S. forces to operate against threats in the region.

Various states and non-state actors within these regions possess the ability to threaten—and have behaved consistently in ways that do threaten—America’s interests. Fortunately for the U.S., these major threat actors are few in number and continue to be confined to three regions—Europe, the Middle East, and Asia—thus enabling the U.S. (if it will do so) to focus its resources and efforts accordingly. Unfortunately, however, when one of these major threat actors does something outrageous as Russia did by invading Ukraine or Iran did by sponsoring the Hamas attack on Israel, the damage is not confined to the immediate region.

In our globally interconnected world, local wars can have global consequences that lead to severe economic, diplomatic, and security problems for the U.S., its allies, and its trading partners. Russia’s assault on Ukraine has sent shocks throughout energy and food markets, causing severe shortages and spikes in costs for nearly every country. One can only imagine the catastrophe that would result if China decided to seize Taiwan or use force to take control of disputed islands or if Iran’s acquisition of a nuclear weapons capability prompted Israel to confront Tehran directly. The question that looms large in any of these scenarios is both simple and fundamental: Is the U.S. military up to the task of defending America’s interests?

America’s military services are beset by aging equipment, shrinking numbers, rising costs, and problematic funding. These four elements interact in ways that are difficult to measure in concrete terms and impossible to forecast with any certainty. Nevertheless, the exercise of describing them and characterizing their general condition is worthwhile because it informs debates about defense policies and the allocation of resources that are necessary if the U.S. military is to carry out its assigned duties. Further, as seen in this 2024 Index, noting how conditions have changed during the preceding year helps to shed light on the effects of policies, decisions, and actions on security affairs that involve the interests of the United States, its allies and friends, and its enemies.

It should be borne in mind that each annual Index assesses conditions as they are for the year in question. This 2024 Index of U.S. Military Strength describes changes that occurred during the preceding year with updates that are current as of October 2023.

Assessments for global operating environment, threats to vital U.S. interests, and U.S. military power are included in the Executive Summary. Factors that would push things toward “bad” (the left side of the scale) tend to move more quickly than those that improve one’s situation, especially when it comes to the material condition of the U.S. military. Munitions can be expended in seconds, and an airplane or a tank can be lost in an instant. Replacing either takes months or years. Similarly, wars unfold at a breakneck pace and can last weeks, months, or years, but their aftermath can extend decades into the future, changing the geopolitical and global economic landscapes in ways that cannot be undone.

Of the three areas measured—global operating environment, threats to vital U.S. interests, and U.S. military power—the U.S. can directly control only one: its own military. The condition of the U.S. military can influence the other two because a weakened America arguably emboldens challenges to its interests and loses potential allies, but a militarily strong America deters opportunism and draws partners to its side from across the globe.

Conclusion

During the decades since the end of the Second World War, the United States has underwritten and taken the lead in maintaining an unprecedented period of peace that has benefited more people in more ways than at any other period in history. Now, however, that American-led order is arguably under the greatest stress since its founding, and some wonder whether it will break apart entirely as fiscal and economic burdens (exacerbated by disruptions like the COVID-19 pandemic, the Russia–Ukraine War, and the attack on Israel) plague nations, violent extremist ideologies threaten the stability of entire regions, competition for scarce resources increases, state and non-state opportunists seek to exploit upheavals, technological innovations in telecommunications and artificial intelligence present opportunity and risk in equal measure, and major states compete to establish dominant positions in their respective regions.

America’s leadership role is very much in question, and its security interests are under substantial pressure. Challenges continue to grow, long-standing allies are not what they once were, and the U.S. is increasingly bedeviled by once-unimaginable debt and domestic discord that constrain its ability to sustain its forces at a level that is commensurate with its interests.

The deterioration of our national defense can still be arrested and reversed, but this will require concerted effort to fulfill our obligations, regain our confidence, restore our armed forces, and preserve the economic strength responsible for sustaining it. If not, the developments that we are observing in the Korean peninsula, Iran, Russia, China, the Middle East, Afghanistan, Africa, and Central Europe will constitute the “first foretaste of [the] bitter cup which will be proffered to us year by year” to which Churchill referred after Munich in 1938 “unless by a supreme recovery of moral health and martial vigor, we arise again and take our stand for freedom as in the olden time.”

The crisis we confront is not unprecedented. Following the conclusion of the Vietnam conflict and American withdrawal, the Defense Department launched an effort led by Andrew Marshall and the Office of Net Assessment under the direction of then-Secretary of Defense Donald Rumsfeld8 to assess the Soviet Union’s growing military forces and compare their force structure and capabilities to ours. The Congressional Research Service9 conducted a parallel effort to contrast the growing divergence and provide a range of urgent recommendations to Congress. Both projects concluded that we were unprepared to meet current and projected Soviet military threats and that, absent the development of new and improved capabilities, deterrence would likely collapse, security would be threatened, and our national interests would be compromised. The Reagan Administration worked with Congress to address the challenges, and our military advantage was restored, contributing decisively to the successful conclusion of the Cold War.

Informed deliberations on the status of America’s military power are therefore desperately needed. It is our hope, as always, that this Index of U.S. Military Strength will help to facilitate those deliberations.

Endnotes