The armies of the Islamic State running roughshod over government forces in Iraq and Syria. Russian little green men infiltrating eastern Ukraine following the military annexation of Crimea. Houthi rebels overthrowing the Yemeni government and seizing large swaths of the country. Taliban fighters seizing an Afghan provincial capital and carving out ever-larger strips of the countryside. Groups inspired by Al Qaeda and the Islamic State attacking government forces in the Sinai, Libya, West Africa and Pakistan.

AirSea Battle seems so yesterday.

The United States unquestionably must maintain its robust naval and air forces. China’s growing air and sea capabilities, coupled with its rising assertiveness, truly do demand a credible U.S. military rejoinder. And the proliferation of so-called anti-access and area denial (A2/AD) threats around the world — from the western Pacific to the Persian Gulf to Syrian airspace — clearly menace vital U.S. interests such as freedom of navigation. Air and sea power will be essential parts of the response to these and other threats.

But in the past year and a half, landpower in the hands of aggressors around the world has made a serious comeback. American land forces are currently deployed across the globe conducting a wide range of military operations. Two, three, or even five years ago, the world looked much different to U.S. policymakers. In the brief glow of the Arab Spring, the “reset” with Russia, the death of Osama bin Laden, and nascent indicators of success in Iraq and even Afghanistan, U.S. policymakers called for a pivot to the Pacific — which, from a military standpoint, is far more of a naval and air theater for the United States than a land theater.

Today, demands on American landpower — to deter and compel adversaries, defend allies, and reassure friends — are significant and growing. Landpower remains a central component of compelling adversaries to relent to American power, as examples around the world suggest. Defeating the Islamic State with airpower has yet to achieve results. It will likely take some sort of ground force to defeat the group in Iraq and Syria. Deterring Russian aggression in Eastern Europe seems equally unlikely to be affected by the threat of U.S. seapower or more NATO air patrols. Reversing the advances of jihadist groups across Asia, the Middle East, and North Africa also seems highly unlikely without capable ground forces that can seize and hold ground, defeat enemy fighting formations, and deny key territory to stubborn adversaries.

The United States cannot — and should not — be the primary provider of land forces in all of these mounting global conflicts. But the growing number of threats on land has pointedly reinforced the need for strong and capable U.S. ground forces. The United States will continue to provide the only globally deployable and sizable land forces that can help support these efforts, and occasionally lead them. Demands for American ground forces around the world — as trainers, advisers, special operators, or combined arms forces to defend friends and deter adversaries — are only going to rise.

Yet the unbending realities of U.S. politics and budgets, even in a dangerous world, make clear that the size of U.S. land forces probably will not increase any time soon. Unless reversed, the 2011 Budget Control Act (BCA) caps the size of the defense budget for the next few years. As we noted in our last column, Congress cannot raise the defense budget without also increasing domestic spending. Prospects for that remain uncertain at best — especially given the looming showdown between the president and Congress about supplementing baseline defense spending through the Overseas Contingency Operations (OCO) account. Furthermore, current U.S. strategy accepts some risk with land forces in the near term, and emphasizes improving air and sea capabilities to meet potential long-term threats from capable state actors, especially in the Pacific.

Strong proponents of landpower argue that this strategy is simply wrong — that the growing dangers of today mean that the United States needs more land forces than are currently planned, not fewer. But failing any relief from BCA budget caps, others argue that Army end strength should not become the bill payer for other U.S. capabilities, especially at sea and in the air.

Under current plans, the total land force will include slightly more than 1.2 million men and women under arms by Fiscal Year (FY) 2019. That figure includes 632,000 people in the active component (450,000 in the Army and 182,000 in the Marines), and another 569,000 people in the reserve component (335,000 in the Army National Guard, 195,000 in the Army Reserve, and 39,000 in the Marine Reserve). By any measure, this would remain a formidable land force — larger than all but a handful of the world’s armies — and would be highly trained, well-led, and expansively equipped compared to any imaginable challenger.

Yet these plans assume some relief from the budget caps. If the caps included in the 2011 Budget Control Act remain intact, then the active component would further shrink by 37,000 people (to 420,000 in the Army and 175,000 in the Marines) and the reserve component would shrink by 30,000 people (to 315,000 in the Army National Guard and 185,000 in the Army Reserve; the Marine Reserve would remain unchanged). In our judgment, these cuts go too far — especially since disproportionate cuts would likely affect direct combat capabilities (what is often called the operational force, as opposed to the institutional or generating force). In a world of exploding land threats, cuts to these levels would potentially expose the nation to too much risk.

Size and end strength matter a lot — but capabilities matter even more. Even if U.S. land forces remain at the currently planned size, the Department of Defense must work harder to squeeze the most military capability out of every dollar it spends. Defense reform is urgently needed, so that the billions of dollars spent every year on skyrocketing internal costs and institutional inefficiencies can be reinvested into combat capabilities. But the Army, and to a lesser extent the Marine Corps, should also reshape themselves around four key principles to maximize their combat power.

Maintain modest but highly ready active duty U.S. land forces. Active duty forces are the most highly trained, ready, and available — and most expensive — forces on hand to respond to crises. Since they train constantly throughout the year, active duty forces are best suited for maintaining sustained proficiency for complex, high-end combat. But their large and growing costs means that the size of the active duty force must remain limited to only those units and personnel who must deploy rapidly to any future conflict. The large numbers of active duty personnel devoted to headquarters, staffs, and overhead must be reduced. The size of the active duty force should also not exceed what can be deployed quickly with available strategic lift. It makes little sense, for example, to pay the high readiness premium for more forces on active duty than can be moved with the available strategic lift that limits their flow into theater. Follow-on forces should rely heavily on the Guard and Reserves.

Better leverage the reserve component — the National Guard and Reserves — to provide land power depth. These land forces reserve components need to be far better integrated with active forces, especially in the Army. More reserve forces also need to be kept at higher levels of readiness so they can respond to crisis more quickly. Rules for reserve availability need to be streamlined, and obsolescent policies (such as the 1:5 ratio for dwell time) about reserve availability should be discarded. Many of these efforts are laboriously making their way through Pentagon staffing now. Blending active, Guard, and reserve units into hybrid units could go far to stretch today’s existing capabilities and raise them to higher levels of training and readiness. This is one of the ideas being considered by the National Commission on the Future of the Army, which is scheduled to issue its final report by February 1.

Continue to buttress and support ground forces of friends and allies to maintain the most collective land power capability. Working “by, with, and through” friends and allies in ground operations should continue to be a central tenet of U.S. strategy in the coming decades. The demand for ground combat capabilities in small wars around the globe is nearly unlimited. Though large-scale efforts to build and sustain security forces in Afghanistan, Iraq, and Syria have been problematic at best and outright failures at worst, more tailored and sustainable approaches to security force assistance can help U.S. partners improve some of their capabilities. The United States should also continue to help its most capable friends and allies maintain targeted high-end capabilities (such as precision weaponry and missile defense) and preserve some irregular skills, now perhaps aimed at conflicts in the “gray zone.”

Design U.S. land forces for expansibility. The size of U.S. ground forces has fluctuated widely over the nation’s history, typically expanding rapidly in wartime and then drawing down after wars end. Even without the 2011 Budget Control Act, with its arcane sequestration provision, the nation’s land forces would likely have been cut significantly in the aftermath of the wars in Iraq and Afghanistan. However, that trend also suggests that at some point — whether it is measured in months, years, or even decades — the size of the ground forces will grow again, most likely in response to a crisis. That means that as the Army and Marine Corps shrink, they need to preserve expansibility — the capability to regenerate new units. This requires, first and foremost, sustaining cadre formations of mid-grade officers and NCOs who would be needed to lead such units. In addition, the services should regularly vet their ability to raise modest-sized units from scratch to ensure they both sustain this expertise and understand and mitigate its many challenges.

Landpower remains a cornerstone of the nation’s military capabilities. Today’s world is exploding with challenges on land, reflecting a trend that shows every prospect of growing. American land forces have repeatedly been the central tool required to prevail in some of the largest conflicts the United States has faced in its 239-year history. And major wars requiring decisive application of large-scale military power are not out of the realm of possibility as the United States faces an ever more turbulent and unpredictable world. Moreover, even now, the spreading threats of gray zone conflicts, insurgencies, hybrid wars, and terrorism are placing ever more demands on current land forces. Yet budget constraints and intractable politics all but assure that neither the defense budget nor the size of the nation’s land forces is likely to rise anytime soon. Given that stark reality, it is time for the United States to stop reducing its land forces while creatively pursuing ways to maximize and sustain its present land warfighting capabilities. Landpower still matters — and with the right approach, the United States can continue to remain unchallenged on this battlefield.

Lt. General David W. Barno, USA (Ret.) is a Distinguished Practitioner in Residence, and Dr. Nora Bensahel is a Distinguished Scholar in Residence, at the School of International Service at American University. Both also serve as Nonresident Senior Fellows at the Atlantic Council. Their column appears in War on the Rocks every other Tuesday.

Photo credit: The U.S. Army