What are the implications of the Department of Defense’s adoption of a one-war standard that is focused on defeating a great-power rival? Hal Brands and Evan Braden Montgomery discuss the gap between America’s global commitments and the military challenges it can realistically meet.
A quiet revolution in American defense strategy is currently underway. The U.S. military is no longer focusing on combating rogue states, terrorist groups, and other deadly, albeit relatively weak, enemies. Instead, the Defense Department is setting its sights on China and Russia: great power rivals that are contesting American military advantages and threatening to reorder the world. “The central challenge to U.S. prosperity and security is the reemergence of long-term, strategic competition by … revisionist powers,” the 2018 National Defense Strategy states.1 Deterring these rivals, and defeating them should deterrence fail, will require far-reaching changes in what the American military buys and how it fights.
The main pillar of this strategy is a new approach to force planning, which outlines how the U.S. military should be built to fight. For more than a generation, the United States maintained a two-war standard to ensure that it could defeat a pair of regional adversaries simultaneously or in quick succession. Now, the Defense Department has adopted a one-war standard geared toward defeating a great-power rival. In other words, rather than planning to win multiple medium-sized wars, the Defense Department is preparing to win a single major war against a formidable competitor, one that can match (at least in some areas) American military might. This shift represents the most significant departure in American defense strategy since the end of the Cold War, and it has tremendous ramifications for a country that still has security commitments — and security challenges — around the globe.
The one-war standard reflects serious strategic thinking and is rooted in real budgetary constraints. It is a recognition that defeating a great-power adversary would be far more difficult than anything the U.S. military has done in decades, and that losing a great-power war would be devastating to America’s global interests. It is meant to galvanize a sluggish bureaucracy to undertake the radical changes necessary to prevent this grim scenario from coming to pass. Yet, it is far more dangerous than its advocates publicly acknowledge.2
The most obvious risk of a one-war standard is that America might need to fight more than one war at a time. In fact, a one-war standard could increase this risk by tempting an opportunistic adversary to use force in one theater while Washington is occupied in another. Proponents of the one-war approach offer a number of options for avoiding a second war, if possible, or fighting it, if necessary, but these options are not promising: They would leave the United States strategically exposed, militarily overextended, or much more reliant on highly escalatory options that lack credibility. And as America loses the ability to handle challenges in more than one theater, it will also lose leverage in peacetime competitions and diplomatic crises. In short, the one-war standard exposes a serious mismatch between America’s global commitments and the military challenges it can realistically meet — a grand strategy-defense strategy gap that may prove extremely damaging in war and peace alike.
Why This National Defense Strategy Matters
At the core of every U.S. defense review is a “force planning construct,” which specifies the number, type, and frequency of conflicts that the American military must be prepared to face.3 This construct is arguably the most important element of a defense review. It establishes what the Defense Department should buy, how it should organize its forces, and what contingencies it should prioritize. In other words, it spells out what the U.S. military must be able to do, and how big and how capable it must be, to achieve the nation’s objectives.
The key innovation of the 2018 National Defense Strategy is its one-war, great-power-centric force planning construct. “In wartime,” the document states, “the fully mobilized Joint Force will be capable of: defeating aggression by a major power; deterring opportunistic aggression elsewhere; and disrupting imminent terrorist and WMD threats.”4 Of these tasks, the first — defeating great-power aggression — is also the most important. As Jim Mitre, who helped develop the strategy, writes, the National Defense Strategy shifts the Department of Defense away from planning for “two simultaneous major wars, in separate theaters against mid-tier enemies,” in favor of a laser-like focus on “defeating aggression by a [single] great power.”5 That means the U.S. military should be sized and shaped to beat China or Russia in a high-intensity war, not to defeat some combination of weaker states such as Iran and North Korea.
The one-war construct is significant because it breaks with every U.S. defense strategy of the post-Cold War era. From George H.W. Bush’s “Base Force” concept to Barack Obama’s Defense Strategic Guidance, multiple administrations have reaffirmed that the United States must be able to prevail in two conflicts simultaneously or nearly simultaneously. In the 1990s, for example, the U.S. military was structured to defeat Saddam Hussein’s Iraq without fatally compromising its ability to fight North Korea. The idea was to ensure that a bad actor in one theater could not exploit America’s preoccupation in another theater. That, in turn, was critical to the credibility of a grand strategy based on upholding stability in multiple theaters around the world. As the 1997 Quadrennial Defense Review declared, a two-war capability is “the sine qua non of a superpower.”6
The Case for the One-War Standard
The 2018 National Defense Strategy thus signals that America must reshape its military for a new era. That shift is based on four key factors. First, and most important, are strategic considerations. Unlike in the 1990s or 2000s, when America’s main opponents were non-state actors or rogue states, Washington’s chief competitors now include resurgent or rising great powers — near-peer competitors, in Pentagon parlance — that pose a serious threat to U.S. military primacy and could seriously challenge American alliance commitments in key regions.
Since the early 2000s, both China and Russia have undertaken far-reaching military modernization programs that have emphasized the tools needed to coerce U.S. allies and hold at bay American forces that would presumably come riding to the rescue. As a result, both countries now combine increasingly advanced capabilities with profound geographic advantages, given that plausible conflict scenarios would unfold in their own back yards. These factors, in turn, would require the United States to project military power into the jaws of Chinese or Russian anti-access/area-denial capabilities in order to defend local allies and partners.7