How much military force does a global superpower require? Answering this question has challenged U.S. leaders and defense planners for more than 20 years. With the collapse of the Soviet Union and the end of the Cold War, the United States found itself the world’s sole superpower, but one without a significant adversary against which to measure the adequacy of its military capabilities. In the immediate aftermath of the first Gulf War, U.S. leaders decided to use the requirement to conduct two major regional conventional contingencies (MRCs) at the same time as the basis for sizing the U.S. military. Every subsequent review of U.S. defense policy and programs has reaffirmed the two-war standard. In fact, every Administration for the past two decades found that a force sized to fight two wars was essential for meeting the ongoing demands for forward presence, crisis response, regional deterrence, humanitarian assistance, building partnership capacity, homeland defense, and support to civil authorities.
Based on some 20 years of analyses and studies as well as the experiences of Desert Storm, Operation Iraqi Freedom, and Operation Enduring Freedom, a two-MRC force should generally consist of 10 Active and eight Reserve Component Army divisions, two to three Marine Expeditionary Forces, 11 aircraft carriers, 120 large surface naval combatants, 38 large amphibious warfare ships, 200 strategic bombers, 20 tactical fighter wings, 400–500 tankers, and 250 airlifters. Such a force would need support from a wide range of enabling capabilities, such as special operations forces; intelligence, surveillance, and reconnaissance systems; cyber defenses; air and missile defenses; and space systems.
Today’s military is too small to meet the two-MRC test credibly. Moreover, the qualitative advantage that the U.S. military has long enjoyed is eroding as advanced military capabilities proliferate around the world. The capabilities of U.S. forces are also deteriorating as platforms and systems age and as critical modernization programs are delayed or even cancelled.
Building a two-MRC force for the 21st century means increasing the size of the U.S. military, modernizing existing platforms and systems, and investing in advanced air, sea, and land capabilities. This will require resources above the levels proposed by the Obama Administration. Over the next decade, building a reasonable two-MRC force for the 21st century will cost roughly $70 billion more per year than the projected cost of the current defense program, which averages approximately $550 billion per year.
Section I: What It Takes to Be a Military Superpower
Since the end of the Cold War, the United States has measured the fundamental adequacy of its force posture in terms of the ability of U.S. forces, without national mobilization, to defeat two nation-state adversaries in geographically separate theaters nearly simultaneously. From the time it was first articulated in 1991, the two-theater-war standard has undergone repeated reviews and revisions. The fundamental reason that the two-theater-war standard still survives is because no credible alternative has ever been proposed. Senior decision makers across five Administrations, Republican and Democrat, have been unable to avoid the reality that, in a world of continuing globalization and growing political and military uncertainty, the U.S. needs a military that is large enough and has a sufficient range of capabilities to cover multiple major military contingencies in overlapping time frames. Such a military would not only fit the character of the post–Cold War threat environment, but also serve a critical deterrence function in an era in which the scale of potential conventional conflicts was seen as decreasing and the ability to resort to nuclear weapons had become less plausible. The 1997 Quadrennial Defense Review (QDR) provided one of the best formulations of the rationale for the two-theater-war standard:
As a global power with worldwide interests, it is imperative that the United States now and for the foreseeable future be able to deter and defeat large-scale, cross-border aggression in two distant theaters in overlapping time frames, preferably in concert with regional allies. Maintaining this core capability is central to credibly deterring opportunism—that is, to avoiding a situation in which an aggressor in one region might be tempted to take advantage when U.S. forces are heavily committed elsewhere—and to ensuring that the United States has sufficient military capabilities to deter or defeat aggression by an adversary that is larger, or under circumstances that are more difficult, than expected. This is particularly important in a highly dynamic and uncertain security environment. We can never know with certainty when or where the next major theater war will occur, who our next adversary will be, how an enemy will fight, who will join us in a coalition, or precisely what demands will be placed on U.S. forces. Indeed, history has repeatedly shown that we are often unable to predict such matters. A force sized and equipped for deterring and defeating aggression in more than one theater ensures the United States will maintain the flexibility to cope with the unpredictable and unexpected. Such a capability is the sine qua non of a superpower and is essential to the credibility of our overall national security strategy. It also supports our continued engagement in shaping the international environment to reduce the chances that such threats will develop in the first place.
If the United States were to forego its ability to defeat aggression in more than one theater at a time, our standing as a global power, as the security partner of choice, and as the leader of the international community would be called into question. Indeed, some allies would undoubtedly read a one-war capability as a signal that the United States, if heavily engaged elsewhere, would no longer be able to help defend their interests. Such a capability could also inhibit the United States from responding to a crisis promptly enough, or even at all, for fear of committing the bulk of our forces and making ourselves vulnerable in other regions. This fact is also unlikely to escape the attention of potential adversaries. A one-theater war capacity would risk undermining both deterrence and the credibility of U.S. security commitments in key regions of the world. This, in turn, could cause allies and friends to adopt more divergent defense policies and postures, thereby weakening the web of alliances and coalitions on which we rely to protect our interests abroad. 
Some 15 years later, the 2012 new strategic guidance for the Department of Defense acknowledged the same basic reality:
As a nation with important interests in multiple regions, our forces must be capable of deterring and defeating aggression by an opportunistic adversary in one region even when our forces are committed to a large-scale operation elsewhere…. Even when U.S. forces are committed to a large-scale operation in one region, they will be capable of denying the objectives of—or imposing unacceptable costs on—an opportunistic aggressor in a second region. 
Every Administration has put its own spin on the two-war standard, sometimes repeatedly. The initial formulation was based on the concern that the United States might need to deal with aggression at the same time in both Southwest and Northeast Asia. Over time, the requirement evolved from maintaining the capability to defeat two conventionally armed aggressors to a more complex formulation in which the U.S. military was asked to be able to conduct a single campaign against a conventional adversary while waging a long-duration counterinsurgency and stability campaign or protecting the homeland against attack and providing support to civil authorities.
This evolution culminated in the 2010 Quadrennial Defense Review, which explicitly attempted to move away from the two-theater-war standard. However, it failed to provide a clear alternative metric for determining the size and shape of U.S. forces. Rather, the 2010 QDR proposed to determine force sizing and composition by using the requirements of a diverse and complex set of scenarios, including long-duration stability operations and the defense of the homeland on par with a major regional conflict (MRC). The Obama Administration clearly acknowledged the inadequacy of this approach in its 2012 new strategic guidance, which returned to the two-theater-war construct, although U.S. operations in the second conflict would be limited to countering an aggressor’s objectives or inflicting unacceptable damage. In his announcement of the new defense strategy in January 2012, Secretary of Defense Leon Panetta clearly articulated the need to maintain capabilities to deal with two major regional conflicts at one time:
Our strategy review concluded that the United States must have the capability to fight several conflicts at the same time. We are not confronting, obviously, the threats of the past; we are confronting the threats of the 21st century. And that demands greater flexibility to shift and deploy forces to be able to fight and defeat any enemy anywhere. How we defeat the enemy may very well vary across conflicts. But make no mistake, we will have the capability to confront and defeat more than one adversary at a time. 
Secretary Panetta even more explicitly advocated the two-conflict standard in his speech to the 2012 Munich Security Conference in front of America’s major allies:
[W]e will ensure that we can quickly confront and defeat aggression from any adversary, any time, any place. It is essential that we have the capability to deal with more than one adversary at a time, and we believe we have shaped a force that will give us that capability. 
Experience also suggests the need for the U.S. military to be prepared to conduct two major long-term operations at a time. Three times since the end of the Cold War, the United States has found itself involved in major theater conflicts. For Desert Shield/Desert Storm in 1990–1991, the U.S. deployed nearly a million soldiers (73 percent were U.S. personnel) from 34 countries. The United States conducted decisive theater operations in Afghanistan (Operation Enduring Freedom or OEF) in 2001 and in Iraq (Operation Iraqi Freedom or OIF) in 2003, overthrowing the regimes in both countries. These two operations morphed into long-term counterinsurgency campaigns involving at their zeniths around 150,000 U.S. troops each as well as significant contingents from allied and partner nations.
An essential premise of U.S. national security since the end of the Cold War has been this nation’s role as the guarantor of global security. The Clinton Administration sought to take advantage of the opportunities provided by the demise of the Soviet Union to define a new approach to U.S. security policy—one based on the opportunities created by the end of the East–West divide to expand the community of democratic states and improve global engagement on a host of issues. U.S. military preeminence was essential to this new strategy and the U.S. role in the world:
First and foremost, we must exercise global leadership. We are not the world’s policeman, but as the world’s premier economic and military power, and with the strength of our democratic values, the U.S. is indispensable to the forging of stable political relations and open trade. 
Almost two decades later, as it sought to articulate its vision for U.S. defense and foreign policies, the Obama Administration had to acknowledge the close intertwining of U.S. military power and peace in the world:
Our country possesses the attributes that have supported our leadership for decades—sturdy alliances, an unmatched military, the world’s largest economy, a strong and evolving democracy, and a dynamic citizenry. Going forward, there should be no doubt: the United States of America will continue to underwrite global security—through our commitments to allies, partners, and institutions; our focus on defeating al-Qaeda and its affiliates in Afghanistan, Pakistan, and around the globe; and our determination to deter aggression and prevent the proliferation of the world’s most dangerous weapons. 
The two-MRC standard also provided a useful hedge against both the near-term danger of a resurgent Russia and the longer-term rise of a true peer competitor, either a single “superstate” or a confederation of adversaries. With respect to the latter, discussions in the early 1990s when the standard was first proposed did not foresee such a situation for at least 20 years. Conceptually, a force structure designed to conduct two relatively large and intense theater campaigns could serve as a counterweight to a hostile, militarizing Russia and simultaneously as the base for an expanded military capability to deter a peer adversary.
The two-MRC standard was never considered a perfect guide to force sizing and modernization. In the absence of a clear and driving threat, such as that provided by the Soviet Union, its role was as a placeholder, allowing defense planners and budgeters to define a useful and affordable military capability that could respond to the range of known demands and unknown future contingencies.
In truth, there have always been some doubts about the ability of the post–Cold War U.S. military to conduct two MRCs precisely at the same time and in the absence of national mobilization. The temporal relationship between the two conflicts was recognized as a problem. Overlapping conflicts placed particular stress on so-called high-demand/low-density systems, the critical enablers that were central to the ability of U.S. forces to gather intelligence, deploy forces, and conduct high-intensity precision operations. In addition, there was continuing uncertainty about the capacity and willingness of regional allies to support U.S. operations. Turkey’s refusal to allow U.S. forces to use it as a staging base for a northern offensive against Iraq confirmed the validity of this concern.
Of far greater concern has been the gap between the appetite of successive post–Cold War Administrations for military forces and their willingness to invest the resources necessary to support the required force structure. Over the past 20 years, the size of the U.S. military has declined by 50 percent while its activity level has increased fourfold, excluding recent conflicts in Iraq and Afghanistan. Even as successive force structure and strategy reviews have reconfirmed the centrality of the two-MRC construct to America’s global leadership, defense budgets have been cut; modernization programs have been reduced, delayed, or even canceled; and maintenance and upgrades of older equipment have been deferred. This process led two senior defense experts to conclude about the ritualized process of the Quadrennial Defense Review:
There is an air of unreality about the whole process, particularly because the last three administrations systematically underfunded America’s armed forces while increasing their deployments and missions abroad. As a result, the military is too small and is forced to use equipment that is too old. Consistent with ongoing obligations in Iraq and Afghanistan, the military cannot fight one regional contingency like Desert Storm, much less two. 
Nevertheless, the two constants in U.S. national security policy for the past two decades have been, first, the centrality of U.S. military preeminence to this nation’s position of global leadership and its goal of a stable international environment and, second, the value of the two-MRC force-sizing construct as both a symbol of that preeminence and a measure of overall adequacy of the force to perform the range of its missions.
Nothing in the evolving global security environment suggests that the U.S. military will be unshackled from the basic requirement to deter if possible, but fight and win if necessary, two geographically separated major theater conflicts in overlapping time frames. Rather the opposite appears to be the case. Core U.S. national security interests and objectives have changed very little since the end of the Cold War and the formulation of the two-theater-war sizing construct. These interests include protecting the U.S. homeland and U.S. citizens everywhere, partnering with allies and friends to provide regional security, ensuring access to areas of vital national interest, securing the global commons, and countering efforts by aggressive powers to dominate important regions of the world.
At the same time, challenges to these interests and threats to U.S. forces abroad and U.S. allies are increasing, not declining. The canonical Southwest and Northeast Asia scenarios remain. Iran is pursuing a hegemonic strategy in the Persian Gulf, supporting terrorist organizations and rogue regimes and continuing a sustained military buildup. North Korea shows no signs of easing its hard-line stance or curtailing its efforts to acquire long-range ballistic missiles and a stockpile of nuclear weapons. Over the past two decades, Pyongyang has engaged in a series of provocative military actions that caused the deaths of South Korean military personnel and civilians. In addition, other parts of the Greater Middle East from Libya and Egypt to Syria and even Pakistan are experiencing political instability, social upheavals, and increased conflict.
The possibility of major theater conflicts in other parts of the world can no longer be ignored. Russia’s new national security strategy identifies the North Atlantic Treaty Organization (NATO) as that country’s principal security challenge. Moscow maintains a military presence in a number of former Soviet republics and fought a short, inconclusive conflict with Georgia in 2008. Russia’s defense minister recently warned that his country might respond to the deployment of theater missile defenses in Europe with a preemptive strike on those sites. China continues to expand and improve its military forces deployed opposite Taiwan. In addition, that country and its southern neighbors have sparred over territorial rights in the South China Sea.
Looking ahead, if the U.S. will be required to conduct a theater campaign along the lines of Desert Storm, OIF, or OEF, it will likely do so under more challenging circumstances than envisioned when the standard was first articulated. Potential adversaries have studied the strategies, tactics, and technologies that the United States employed to win decisively in prior theater conflicts. These countries are participating in the global proliferation of advanced conventional weapons. A number of these regional actors are investing heavily in anti-access/area denial (A2/AD) capabilities primarily to counter the ability of the United States and its allies to project power into regions of interest using their traditional advantages in air and naval power to achieve decisive military outcomes as they did in earlier major theater conflicts.
A number of prospective regional adversaries also are investing in a range of unconventional capabilities and operational methods to counter or circumvent traditional U.S. advantages in conventional military forces. Some of these countries have extensive programs to develop, stockpile, and deploy weapons of mass destruction (WMDs). A number of prospective adversaries also have developed extensive ties with non-state actors and terrorist groups seeking to develop what some analysts have termed a “hybrid threat,” such as the military relationship between Iran and Hezbollah.
Even as prospective theater adversaries build up their military capabilities and acquire more advanced weapons and systems, the ability of regional allies to contribute to their own defense and the security of their regions is changing. Some U.S. allies are reducing their defense budgets and cutting their military capabilities. Budgetary pressures in Europe have forced a number of NATO allies to reduce the size of their armed forces and scale back modernization programs. However, many U.S. allies in the Middle East and East Asia are expanding and modernizing their force structures.
Future major theater conflicts will likely be more challenging than those of the past several decades, and they may not be limited to foreign theaters. A theater conflict could easily involve actions against the U.S. homeland or overseas bases outside the primary region of hostilities. Such attacks on the homeland could either be preemptive à la Pearl Harbor, intended to undermine a U.S. response, or in retaliation for U.S. actions against a theater adversary. Possible homeland events could range from terrorism and acts of sabotage to cyber attacks to the use of a WMD.
Not all of the trends are negative. Since the inception of the two-MRC standard, the United States has invested in a range of platforms, systems, and capabilities that have significantly enhanced its ability to conduct large-scale joint and combined operations. In this regard, the contrast between Desert Storm in 1991—the first MRC in Southwest Asia—and Operation Iraqi Freedom in 2003 is telling. The 1991 coalition to liberate Kuwait deployed nearly 1 million combatants, more than half of them U.S. personnel. In 2003, the march to Baghdad employed only 248,000 U.S. personnel along with some 50,000 allied soldiers, primarily from Great Britain. 
Improvements in military equipment significantly affected the conduct of the two MRCs. In 1991 only 7.5 percent of the air-delivered ordnance was precision-guided, but the proportion had increased to nearly 65 percent in 2003.  Over this period similar radical changes occurred in unmanned aerial systems, real-time strategic and tactical communications, stealth aircraft, and theater missile defenses.
Today, the two-MRC standard, the sine qua non of superpower status and possibly the most critical measure of a viable U.S. national security strategy, is at risk. The new defense strategy attempts to have it both ways. It professes to adhere to the two-major-theater-war standard while proposing for the second contingency something a great deal less. In the 1990s, this lesser standard was tried and found wanting. Given the number, variety, and war-waging potential of current and emerging threats to U.S. national security, maintaining a U.S. force structure sized against any standard less than fighting and winning two nearly simultaneous major theater conflicts invites the very instability that U.S. defense strategy is intended to deter. For the foreseeable future even more than in the recent past, the U.S. military’s ability to meet a two-MRC standard will be the measure of this nation’s status as a superpower and a primary engine driving its role as a global leader.
This paper defines the essential quantitative and qualitative characteristics of a U.S. force structure required to meet the two-MRC standard for the near term and midterm. Section II examines the evolving character of the two-MRC standard in the post–Cold War era with a particular focus on future theater conflicts and criteria for sufficiency. Section III examines the evolving military threat to regional security and U.S. vital interests and its effect on the two-MRC standard. Section IV defines a 21st-century standard for a two-MRC force structure. Section V develops a top-level assessment of the costs associated with sculpting the planned force structure to meet the two-MRC test. Finally, Section VI recommends the steps that the Administration should take to address the shortfalls of the current U.S. force structure, one based on the new defense strategy, so as to enable that force to meet the goal of fighting and winning two nearly simultaneous MRCs.