Defense In Depth
Why U.S. Security Depends on Alliances—Now More Than Ever
Missile material: land-to-air missiles in Tokyo, April 2012. (Toru Hani / Courtesy Reuters)
Traditionally, the core purpose of the U.S. Army has been to fight and win the United States' wars. Since World War II, this has meant planning for overseas operations to defend friendly countries against invasion, seize and hold territory, and overthrow despotic regimes. But the protracted counterinsurgency campaigns in Afghanistan and Iraq, like the one in Vietnam a generation earlier, marked a departure from the army's preferred way of war. Today, with U.S. forces out of Iraq and leaving Afghanistan, an intense debate is under way about what kind of army the United States needs.
The answer, according to most analysts, is a smaller and lighter one. The Obama administration's "pivot" toward Asia, a region traditionally dominated by air and naval forces, suggests a lesser role for the army in carrying out U.S. strategy. So does the distaste among politicians for another large-scale counterinsurgency, as do the sizable budget cuts that are now hitting the Defense Department. As the U.S. military's most labor-intensive force, the army is most affected by the rapid rise in personnel costs, which have shot up by nearly 50 percent over the past decade. Given these strategic and budgetary headwinds, the conventional wisdom holds that the army will bear the brunt of the defense cuts -- and that it will decline precipitously in relevance.
The conventional wisdom, however, will prevail only if the army fails to adapt to its changing circumstances. Since the 1990s, the United States' rivals have dramatically increased their capacity to deny Washington the ability to project military power into critical regions. To date, the air force and the navy have led the U.S. response. But the army should also contribute to this effort, most critically with land-based missile forces that can defend U.S. allies and hinder adversaries from projecting power themselves. The army should thus shift its focus away from traditional ground expeditionary forces -- mechanized armor, infantry, and short-range artillery -- and toward land-based missile systems stationed in critical regions. By doing so, it can retain its relevance in U.S. defense strategy.
THE LIMITS OF LAND WARFARE
In planning for the post-Afghanistan era, the army has focused on two major efforts. The first involves expanding its forward presence to build up the defense capacity of foreign militaries using special operations forces and brigades assigned to specific regions. The second picks up where the army left off before 9/11, stressing the importance of ground forces that can decisively defeat adversaries by blocking invasions and toppling hostile regimes.
The problem is that the United States may be unable to defeat future opponents by routing their armies, controlling their territory, and deposing their leaders. Indeed, with the exception of during World War II, these objectives have rarely been achieved. During the Cold War, the United States and its NATO allies planned to defend Western Europe from the Warsaw Pact but harbored few illusions they could ever decisively defeat the Soviet Union without resorting to nuclear weapons. It was only in the 1990s that the United States first considered the prospect of invading and occupying rogue states as a strategic objective.
As the postinvasion insurgencies in Afghanistan and Iraq revealed, decisive victory is often an elusive goal, and today's list of potential adversaries does not offer much hope. Invading and occupying Iran (let alone a nuclear-armed Iran) would be neither desirable nor feasible. It strains credulity even further to imagine major land combat with China or Russia. That leaves a conflict with North Korea as the most plausible scenario for the army's preferred way of war. But South Korea, populous and wealthy, probably needs little assistance to defend itself against a land invasion.
Meanwhile, very few countries are modernizing their forces for classic ground offensives (India and Pakistan being the biggest exceptions). The broader trend in warfare is away from invasions and occupations and toward more coercive and nontraditional uses of ground forces. The Chinese and Iranian armies, for example, have built long-range rocket forces not to wage war against other land forces but to conduct coercive missile campaigns against neighboring states and to contest access to nearby seas. The Chinese military has gone so far as to establish its Second Artillery Corps as a separate service, entrusted with China's long-range missile and antisatellite capabilities.
These missile-intensive forces are better at denying opposing forces the ability to project power than conducting cross-border invasions. They represent the leading edge of so-called anti-access/area-denial (A2/AD) systems -- along with air defenses, antisatellite weaponry, advanced fighter aircraft, quiet diesel submarines, mines, and cyberweapons -- which are raising the costs for outside countries to project power. Such capabilities will make it far more difficult to deploy U.S. forces in distant theaters and conduct joint operations.
In particular, A2/AD capabilities will severely limit the U.S. Army's ability to conduct expeditionary warfare. Ports and airfields, the traditional gateways into overseas theaters, will be easy targets for enemy missiles, as will the stockpiles of equipment positioned ashore that are needed to support army forces flowing into the theater. With enemy missiles also threatening the bases that host U.S. fighter aircraft, the United States may soon enjoy only transient air superiority at best, leaving soldiers on the ground more vulnerable to air strikes. Given advances in underwater mines and submarines, enemies could threaten vital maritime routes. To make matters worse, states may not be the only actors developing A2/AD capabilities; irregular forces could also arm themselves with guided mortars, artillery, and rockets, particularly if they have a state sponsor. Hiding in urban safe havens, insurgents could use these highly accurate weapons to kill large concentrations of occupying forces.
Together, these trends suggest that this century will see dramatically fewer cross-border land invasions than previous ones. Large powers, such as Russia, will undoubtedly retain the ability to invade small neighbors, such as Georgia. Nevertheless, all great powers -- not just the United States -- will have a much harder time projecting power overseas. It will be much easier for any given state to deny others the ability to control the land, air, or sea in its vicinity than for that state to achieve control of those same domains itself.
MISSILES TO THE RESCUE
In response to growing A2/AD threats, the U.S. Air Force and the U.S. Navy have developed a new operational concept called "air-sea battle" -- a plan for projecting power into vital regions where access is increasingly constrained. The army need not feel left out, since it could make vital contributions to the air-sea battle effort. Doing so, however, would require it to reduce its traditional emphasis on expeditionary land warfare and instead focus on establishing a constellation of forward-based missile forces stationed on the territory of U.S. allies and partners. Such a shift would represent a major change in course for the army. Although it possesses some missile capabilities for air and missile defense, as well as for short-range land attack, the army currently lacks options to strike targets further than 300 kilometers away and has no antiship missiles whatsoever.
Taking a page from the playbooks of China and Iran, the U.S. Army should establish its own A2/AD systems to deny would-be regional hegemons the ability to project power. A distributed network of ground-based missile forces could act both as a shield, protecting air and naval forces as they entered the theater, and as a sword, striking the enemy directly from afar -- destroying aircraft, shooting down missiles, sinking ships, and attacking land targets. These forces would include new classes of mobile and fixed launchers that the army would have to develop and field. And like the U.S. Navy's vertical launching system, which can fire a variety of missiles, they should be capable of firing interchangeably antiship, antiaircraft, and land-attack missiles, as well as missile defense interceptors.
The army's new missile systems would prove especially useful in the western Pacific, where the army could construct antiship missile sites and conceal mobile missile launchers throughout the string of islands stretching from Japan to the South China Sea. These systems would help U.S. allies such as Japan and the Philippines defend themselves against potential Chinese aggression and limit the Chinese navy's freedom of maneuver during a crisis. Likewise, in the Persian Gulf, such forces based in Kuwait, Qatar, and the United Arab Emirates might serve as the core of a new regional defense posture. They could link together the missile defense capabilities of the Gulf Cooperation Council states and help deter Iran from launching missiles or attempting to close the Strait of Hormuz.
Land-based missile forces would have a number of advantages over their air- and sea-based counterparts. They can rely on underground fiber-optic communications rather than satellite communications, making them less vulnerable than aircraft and ships to communications jamming and antisatellite operations. They can have far deeper magazines of missiles and sustain more firepower than fighter aircraft, destroyers, or submarines. Targeting ships with cruise missiles launched from the shore would also cost far less than fielding a naval force to do the same task. Meanwhile, using ground forces rather than fighter jets for air defense would free up more aircraft for offensive strikes.
When it comes to missile defense, ground-based forces would be in the best position to take advantage of the most promising technology on the horizon: directed-energy weapons. These weapons channel electromagnetic radiation, particle beams, or microwaves to destroy targets. Within a decade, it will be possible to field high-powered laser weapons and a high-powered microwave system, which would offer virtually unlimited shots and dramatically reduce the cost per interception. Because directed-energy weapons systems depend on access to major power and cooling sources, requirements that are at odds with mobile forces, the army's leadership has historically shown little interest in the technology. Yet if the army began building overseas garrisons, it could draw on larger, stationary power sources for these weapons.
Because land-based missile forces would be forward stationed in critical regions, they would be a tempting nearby target during a crisis. So they would need to be highly survivable. That would require creating a mixture of control stations, weapons caches, and launching sites that were dispersed, concealed, and located underground, and it would require fielding mobile and camouflaged radars and missile launchers that could evade attack. These forces would also have to be networked. Ideally, the army would provide the backbone of communications and intelligence to link together similar capabilities possessed by the United States' partners in a given region. Finally, the army could also train U.S. allies, helping them field their own A2/AD capabilities and so reduce the burden on U.S. forces.
Without a new set of weapons, forward-stationed land-based missile forces could only hit land targets that were less than 300 kilometers away -- too short for launching strikes against potential adversaries, such as China or Iran, that could place their key assets beyond those ranges. To maximize the deterrent value of its land-attack missile forces, the army would need to extend their range. Doing so would have the added benefit of imposing costs on major rivals, forcing them to spend resources on their own expensive missile defense systems.
But as things stand now, if the army tried to follow this path, it would run into an arms control wall. The Intermediate-Range Nuclear Forces Treaty, signed in 1987 by the United States and the Soviet Union, prohibits the United States and Russia from possessing land-based missiles with ranges between 500 and 5,500 kilometers -- the range that might be required for hitting targets in larger countries. After the treaty was ratified, the U.S. Army scrapped its intermediate-range Pershing II ballistic missiles, in essence bowing out of the interservice competition to provide long-range strike capabilities.
The United States would almost certainly have to withdraw from the Intermediate-Range Nuclear Forces Treaty for the army to get back into the long-range strike business. Leaving might not be so bad: while China has become a world leader in exactly the type of land-based missiles the treaty bans, the United States has largely turned its back on them. Nor would leaving be so difficult, since Russia also looks willing to walk away from the treaty. Withdrawing could herald the beginning of a revolution in the way the U.S. military thinks about ground forces -- one the Chinese have already experienced.
Emphasizing land-based missile forces would allow the U.S. Army to contribute meaningfully to the United States' strategic goals. By stationing such capabilities in friendly host countries, the army would reassure regional allies and enhance deterrence. It would help the United States check its rivals by constraining their ability to project power, just as they are doing to it. And the army would be creating local safe areas that would allow U.S. air, maritime, and mechanized ground forces to enter overseas theaters.
This plan would require major changes in the structure of the army. The army would have to develop new organizational units optimized for long-term stationary deployments rather than expeditionary operations. These missile regiments would have to integrate personnel and capabilities from various parts of the army, including the Field Artillery branch, the Air Defense Artillery branch, and the Space and Missile Defense Command.
Cultural obstacles would also have to be surmounted. The new capabilities would have to come from the parts of the army not focused on maneuver warfare -- institutional orphans that have fared poorly in recent decades in the army's internal struggle for resources and power -- and they would have to overcome resistance from armor, infantry, and field-artillery commanders, who dominate the upper ranks of the army today.
In a time of declining resources, moreover, military institutions have a natural tendency to try to retain their current composition, albeit on a smaller scale, rather than grow entirely new combat arms at the expense of more mature branches. Thus, establishing new missile forces would require strong champions within the army, as well as on Capitol Hill.
Such an expanded role for the army would not be without precedent. In the aftermath of the War of 1812, the United States turned to the army to build a string of coastal fortifications to protect U.S. ports, and for many decades following, coastal defense remained the army's principal mission. But in the aftermath of World War II, with the U.S. Navy patrolling the Atlantic and the Pacific, the army retired its coastal artillery. The time has come for the army to resurrect its coastal defense mission -- not to protect American shores but to defend critical overseas theaters.
The creation of new missile forces would not portend the demise of traditional mechanized ground forces in the U.S. Army. Rather, it would establish a new pecking order in a force now dominated by tanks, artillery, and infantry. Paradoxically, establishing the army's own forward-stationed A2/AD capabilities may be the best way to preserve the viability of expeditionary ground forces, by providing them a gateway to overseas theaters. Nevertheless, just as the battleship was gradually replaced by the aircraft carrier after World War II, in the coming era, the dominance of armored vehicles and mechanized infantry is likely to wane. Embracing this trend, rather than resisting it, is the best way for the army to ensure its continued relevance.