Skip to main content

Revisiting the roles and missions of the armed forces

Note: Michael O’Hanlon testified before the Senate Armed Services Committee, arguing in favor of the rough balance of resources that has characterized the U.S. armed forces in the past. O’Hanlon’s comments focused on his latest book “The Future of Land Warfare.”

Greetings, Mr. Chairman, Mr. Ranking Member, and other Senators on the Committee. It is an honor to testify today as we stretch our imaginations to postulate what the future of warfare may be like—and thus what demands may be placed on different elements of America’s military. I am here to argue in favor of the rough balance of resources that has characterized the U.S. armed forces in the past. My purpose is not to argue that landpower should be the preeminent military tool of the United States. Rather, I would like to challenge those who claim that its time has come and gone—and that the U.S. Army’s size and budget should decline accordingly. I strongly disagree. An Army of some million soldiers, active and Reserve and National Guard, remains roughly the right size for the United States going forward—and in fact, that is a rather small and economical force relative to the scale of challenges and threats that I foresee. Moreover, that Army should continue to prepare for a wide range of possible scenarios, challenges, and missions. We cannot opt out of certain categories of warfare based on some crystal ball we purport to possess; the United States has always been wrong when it tried to do so in the past. To paraphrase the old Trotsky’ism, we may not think we have an interest in large, messy, dangerous ground operations in the future—but they may have an interest in us.


In recent years, Americans have understandably gotten tired of land warfare. Fatigued by Iraq and Afghanistan, rightly impressed by special forces, transfixed by the arrival of new technologies such as drones, and increasingly preoccupied with a rising China and its military progress in domains ranging from space to missile forces to maritime operations, the American strategic community has largely turned away from thinking about ground combat.[1] This is actually nothing new. Something similar happened after the world wars, Korean and Vietnam wars, and Operation Desert Storm in 1991 as well. That last time, debate shifted to a supposed revolution in military affairs. Many called for a major transformation in American military forces to respond to that presumed revolution, until the 9/11 attacks returned military analysis back to more practical and immediate issues. But now the strategic debate seems to be picking up about where it had left off at the turn of the century—except that in the intervening 15 years, remarkable progress in technologies such as unmanned aerial systems have provided even more grist for those favoring a radical transition in how militaries prepare for and fight wars.

Much of this debate is welcome. Even if futurists understandably tend to get more wrong than right in their specific recommendations, a debate in which they challenge existing Pentagon rice bowls is preferable to complacency. As long as the burden of proof is on those who would dismantle proven concepts and capabilities when proposing a whole new approach to military operations and warfare, a world of too many ideas is preferable to a staid, unimaginative one of too few. The history of military revolutions suggests that established superpowers are more likely to be caught unprepared for, even unaware of, new ways of warfare than to change their own armed forces too much or too fast.

That said, pushback against transformative ideas will often be necessary. We have seen many unrealistic military ideas proposed for the post-World War II American armed forces, from the Pentomic division of the 1950s that relied on nuclear weapons for indirect fire, to the flawed counterinsurgency strategies of the 1960s, to the surreal nuclear counterforce strategies from Curtis Lemay onward in the Cold War, to the dreamy Strategic Defense Initiative goals of the 1980s, to the proposals for “rods from God” and other unrealistic technologies in the revolution in military affairs debate of the 1990s. As such, wariness about new ideas is in order. Even in a great nation like the United States, groupthink can happen, and bad ideas can gain a following they do not deserve. Also, the United States has a history of cutting its ground forces too far and too fast after major challenges or conflicts have passed. For example, after World War I, we downsized until we had only the 17th largest army in the world as World War II approached; after the latter conflict, we cut the Army so fast that Task Force Smith was routed by the North Koreans just five short years later, in 1950.

One hears much discussion again today about the supposed obsolescence of large-scale ground combat. Official American policy now leans in that direction too, as codified in the 2012 Defense Strategic Guidance and 2014 Quadrennial Defense Review, largely a result of frustrations with the wars in Iraq and Afghanistan. Accordingly, the 2012 Defense Strategic Guidance, released under the signature of then-Secretary of Defense Leon Panetta with a preface signed by President Obama, states flatly that “U.S. forces will no longer be sized to conduct large-scale, prolonged stability operations.[2] Later that same year, the Pentagon carried out a so-called Strategic Capabilities and Management Review that examined the option of reducing the Army to just 380,000 active-duty soldiers.[3] Subsequently, the Ryan-Murray budget compromise of late 2013 and other considerations led to a less stark goal of 440,000 to 450,000 active-duty soldiers. But the 2014 Quadrennial Defense Review again dismissed the plausibility of large-scale stabilization missions, albeit somewhat more gently, stating that “Although our forces will no longer be sized to conduct large-scale prolonged stability operations, we will preserve the experience gained during the past ten years of counterinsurgency and stability operations in Iraq and Afghanistan.”[4] The emphasis changed somewhat, but the fundamental point was the same. Ground warfare, or at least certain forms of it, was not only to be avoided when possible—certainly, that is sound advice—but not even truly prepared for. That may be less sound advice.

There are lots of reasons to believe that, whether we like it or not, ground warfare does have a future, and a very significant one at that. Nearly three-fourths of the world’s full-time military personnel, almost 15 million out of some 20 million, are in their nations’ respective armies.[5] Most wars today are civil wars, fought within states by ground forces. Interstate wars are rare, but when they do happen, they generally involve neighboring states and generally involve a heavy concentration of ground combat. America may be far away from most potential conflict zones, putting a greater premium on U.S. long-range strike including air and naval forces than is the case for most countries. Yet the United States works with more than 60 allies and security partners that tend to emphasize their own armies in force planning, and tend to worry about land warfare scenarios within or just beyond their own borders. Iraq and Afghanistan revealed the limitations of standoff warfare, and the problems that can ensue when the nation places severe constraints on its use of ground power (especially in the first few years of each conflict).

Here is another problem with the trend of our current national thinking: since the Cold War ended, the U.S. Army like much of the American armed forces has been built around the prospect of fighting up to two major regional wars at a time. That thinking has evolved—especially in the years when the United States was actually fighting two wars at once, in Iraq and Afghanistan (and in the process eliminating one of the threats that two-war scenarios had been built around, the government of Saddam Hussein). Former Secretary of Defense Donald Rumsfeld’s 2006 Quadrennial Defense Review began to shift the paradigm somewhat. The Pentagon’s 2012 Defense Strategic Guidance and 2014 Quadrennial Defense Review moved further away from a two-war construct without jettisoning it altogether. Now, in the second of the two overlapping wars, it is deemed adequate to “inflict unacceptable costs” on an adversary.[6] But the vagueness of that latter standard, deterrence by the threat of punishment, and changes in the international security order, suggest that perhaps it is time to think afresh about the future of the U.S. Army and the other services. Planning for regional conflict will have to be a component of future force sizing, but with less specificity about likely foes than in the past, and with a fuller range of considerations to complement the contingency analysis.

Some would counsel against preparedness for plausible military missions on the grounds that by being prepared, we might stray into conflicts that would have been best avoided. The 2003 Iraq War may be a recent case in point—a “war of choice,” in Richard Haass’s pithy depiction, that would surely not have been undertaken without a ready and fairly large standing military.[7] But for every such case in U.S. history, there are probably several—as with the world wars, and Korean War—in which lack of preparedness proved an even greater problem. Moreover, in Iraq and Afghanistan, improper preparation for a certain type of fighting arguably made the initial years in both these wars far less successful than they might have been. Nor is it so clear that the United States is really spoiling for military action abroad. Americans may not be as restrained in the use of force as they often like believe about themselves. Yet at the same time, casualty aversion—and, more recently, a national souring about the kind of ground operations conducted in Iraq and Afghanistan—impose important constraints on action as well. Deliberately staying militarily unprepared for plausible missions, as a way of avoiding unsuccessful military operations abroad, thus seems an unwise and highly risky strategy for the nation.


In the interest of brevity, I will conclude this written testimony with a list of the ten scenarios that I develop and analyze in my new book. None except perhaps the Syria contingency is individually likely. But all bear watching. Each could seriously threaten major American national security interests including even the basic safety of the homeland if it took place. As such, while we might try (and arguably should try) to stay out of most of them even if they begin to unfold, we might also find that there is ultimately little choice but to intervene as part of a joint, coalition operation. And for several in particular, maintaining the capacity to conduct them promptly and effectively could strengthen deterrence, making the very possibility of war less than it would be otherwise. Here is my list:

  • A Russian invasion threat to the Baltic states
  • A second Korean war, including possible Chinese involvement
  • A maritime conflict between China and Japan or the Philippines that spills over onto land
  • A fissioning of Pakistan, perhaps combined with a complex humanitarian emergency sparked by a major natural disaster in South Asia
  • Indo-Pakistani war, perhaps over a terrorist strike, with Kashmir providing the spark
  • Iranian use or threatened use of nuclear weapons against a neighbor
  • A major international stabilization operation, as in Syria after a negotiated peace
  • Civil war accompanied by terrorism and perhaps a biological pandemic within Nigeria
  • Increase in the brutality and reach of criminal networks in Central America
  • A major domestic emergency in the United States

Consideration of these scenarios leads me to advocate a million-soldier U.S. Army, similar to today’s capability, with roughly the current mix between active component and reserve component forces. The Marine Corps would retain roughly its current size and strength as well. Under my proposal, the ground forces would be sized, equipped, trained, and prepared for what I call a “1+2” framework—with the “1” contingency being a large-scale conflict (like some of the more demanding operations suggested above, such as Korea) and the “2” most likely long, multilateral operations involving some combination of stabilization, relief, counterterrorism, deterrence, and assistance to local partners. All three operations could occur at the same rough time period (and if they did, we would need to start growing the Army as well, in anticipation of possible further demands).

Such messy missions may not be what we want as a nation. They certainly are not what our brave soldiers (and other members of the joint force, as well as diplomats and aid workers) might prefer to conduct in faraway lands. But in this complicated, huge, interdependent, dangerous world, they probably will be in our future whether we like it or not.

[1] For good treatments of the capacities of special forces, that at the same time do not overstate their realistic roles or falsely imply the obsolescence of major combat units, see Phillip Lohaus, A Precarious Balance: Preserving the Right Mix of Conventional and Special Operations Forces (Washington, D.C.: American Enterprise Institute, 2015); and Brian S. Petit, Going Big by Getting Small: The Application of Operational Art by Special Operations in Phase Zero (Denver, Colorado: Outskirts Press, 2013).

[2] Department of Defense, “Sustaining U.S. Global Leadership: Priorities for 21st Century Defense,” Washington, D.C., January 2012, available at

[3] Michael E. O’Hanlon, “Sizing U.S. Ground Forces: From ‘2 Wars’ to ‘1 War Plus 2 Missions,’” Washington Quarterly, vol. 37, no. 1 (Spring 2014), pp. 151-164, available at’Hanlon_PDF.pdf.

[4] Department of Defense, Quadrennial Defense Review (Washington, D.C.: March 2014), p. vii, available at

[5] International Institute for Strategic Studies, The Military Balance 2014 (Oxfordshire, England, 2014).

[6] Secretary of Defense Chuck Hagel, Quadrennial Defense Review 2014 (Washington, D.C.: Department of Defense, 2014), p. 22, available at s/2014_Quadrennial_Defense_Review.pdf.

[7] Richard N. Haass, War of Necessity, War of Choice: A Memoir of Two Iraq Wars (New York: Simon and Schuster, 2009).

Get daily updates from Brookings