https://warontherocks.com/2020/08/distilling-the-essence-of-strategy/
Some US analysts suggest, often vaguely, that China’s A2/AD investments work in tandem with its blue-water navy investments, including its aircraft carriers, posing an offensive threat.20 They contend that China’s investments reveal an aggressive strategy, justifying greater US expenditure. However, whether or not China’s strategy is aggressive in the long term, its current operational concept, which features A2/AD technologies, is primarily defensive and ill-suited to offensive goals.
China’s current operational concept is primarily defensive and ill-suited to offensive goals.
A2/AD capabilities are good servants of defensive strategies such as the current stated US strategy. Defenses succeed, in principle, by driving up the costs an attacker would suffer in a war, degrading its will to fight or deterring its attack in the first place. Those costs include not only direct losses of troops and materiel, but also the expensive countermeasures taken to avoid such losses.
While A2/AD systems excel at defense, they are far less useful in supporting offensive military postures. Distance imposes the biggest limit on A2/AD capability. In coastal A2/AD’s modern incarnation, islands obstruct radar, and the curvature of the earth limits it with a horizon, so A2/AD systems cannot locate and attack distant targets.21 Missiles also lose effectiveness with distance, because their target can move and avoid being hit during the time it takes the missile to fly downrange.
China may be trying to extend its A2/AD range by building artificial islands. However, the man-made islands are too small to allow for the cover and mobility that real land offers, and supplies for Chinese forces on these islands would be limited, as they are for sea-based US forces. Any Chinese A2/AD forces based on tiny maritime features would not gain the same relative advantages that home-based A2/AD forces do. For these reasons, the effective range of China’s A2/AD systems is the horizon of its missile-guiding radars on or near its coast.22
It is true that even the limited range of China’s home-based A2/AD forces extends far enough to be relevant to some potential war scenarios. For example, some defense analysts warn about military threats to Taiwan or the Senkaku Islands, and China’s improved A2/AD capabilities are often part of the warning.23 The general claim is that A2/AD capabilities could knock US forces out of a war—or keep them out through deterrence—and then allow China to go on offense.24 So these analysts argue that US forces must do whatever it takes to maintain their ability to operate within range of China’s defenses.
That view overlooks the opportunity to deter Chinese aggression with a more defensive posture. China’s A2/AD investments limit the US military’s capability to promise to inflict punishment against the Chinese homeland in case of a Chinese offensive, but punishment is not the only way to deter an attack.25 Countries are more likely to launch offensives when they perceive an opportunity to win quickly at modest cost.26 And none of China’s A2/AD investments would help Chinese attackers achieve a quick, decisive victory against US allies’ defenses.
Punishment is not the only way to deter an attack.
Enhancing US allies and partners’ A2/AD capabilities would tip the balance even further in their favor. If China’s East Asian adversaries can promise to inflict substantial casualties on an attacking Chinese force, then they can deter a Chinese attack without having US military forces threaten a counter-attack against China itself. The key is for the United States and its allies to adopt the most effective means to deny China the expectation of a quick, low-cost victory.
The Defensive Advantage
Projecting power over distance is difficult, especially when it means crossing substantial bodies of water and air. Attacking platforms need to carry much of the fuel and munitions their missions require onboard, making them larger and easier to detect in the sea and air where concealment is limited.27 If an attacker contemplates conducting an amphibious assault, as would be required for China to attack many US allies, the attacker’s problems multiply. Defending forces can target the large, vulnerable ships that transport troops and concentrate their firepower at the limited number of suitable landing spots.
Defenders have less ground to cover than attackers to get to fights, so they can mass forces more easily than attackers and reinforce troops faster. Defenders on land have more space to deploy surveillance as well as strike systems and more ability to conceal them among the terrain’s features than air- and sea-based attackers have. With nearby supply, surveillance systems and weapons have less need to carry fuel or munitions, which allows them to be smaller, more mobile, and thus harder for an enemy to target.28 Familiarity with local geography and conditions—and with what is normal background clutter—helps sensors and their operators pick out attacking forces in nearby skies and seas.29 And operating radar is easier on defense because defenders have greater opportunity to employ self-defense techniques like decoys and intermittent emissions from dispersed platforms.
Political advantages of defense buttress these technical ones.30 Defensive wars are easier to justify, for one. That is useful in maintaining public support at home and credibility with rivals. Defensive military operations, in service of defensive strategic aims, fit within the political framework that has been sold to the public in the United States and its allies and within the legal terms of the mutual defense pacts that make up the existing US alliance network.
Pitfalls of an Offensive Defense Strategy
Unfortunately, the United States has not yet moved to capitalize on the growing advantages of defensive operations. Instead, it has labored to overcome China’s A2/AD gains, seeking to maintain military dominance in China’s near abroad in the name of defending Asian allies, spending heavily on technology intended to aid US military operations within the range of A2/AD defenses.31 Specifically, the Trump administration’s National Defense Strategy recognized the return of great power competition and the potential challenge of fighting China, and it concluded that the United States must spend vastly more on speculative and risky offensive systems to try to keep doing, operationally, what the US military has been doing for the past couple of decades.32
Planning to fight inside China’s A2/AD envelope entails significant costs, both in terms of money and reduced military effectiveness. The US military is developing capabilities to jam or spoof radar that would guide Chinese missiles and attack aircraft, to improve fleet missile defenses, and to build a more survivable long-range bomber. These are all expensive projects. Moreover, even the best tactical defenses for ships have limited capability. Multiple attacking missiles can overwhelm the number of defensive missiles on a ship, and the ship’s limited size means it can only carry so many ship-defense munitions.33 Worse, every ship-defense munition loaded onto a ship takes space away from other systems and munitions that the ship needs to conduct its (potentially offensive) mission.
The other element of the US effort to maintain its offensive operational concept involves preparing to directly attack China’s defenses—launching air strikes to destroy thousands of Chinese military sites like missile launchers, communications systems, fixed radar and other sensors, and various other targets relevant to the successful operation of China’s air defenses and anti-ship missiles.34 To Beijing, these plans may look like a US capability to destroy China’s defenses with a US first strike, perhaps aimed at overthrowing Communist party rule. Chinese leaders may reasonably fear that the United States has offensive strategic intentions, despite US leaders’ claims to be only interested in defending US allies. In response, China might well arm more heavily, especially with nuclear weapons, which would drive up US spending without achieving relative gains for the United States.35 These are the fruits of exacerbating the security dilemma by implementing an offensive operational concept.
To Beijing, existing plans may look like a US capability to destroy China’s defenses with a first strike.
Beyond the risk of an arms race, US plans for operations that include conventional strikes against the Chinese mainland are downright dangerous. As Georgetown University political scientist Caitlin Talmadge points out, such strikes might push the Chinese government to escalate a conflict to the nuclear level.36 Chinese nuclear early warning and command-and-control systems may be intermixed with the A2/AD systems that the United States plans to destroy or blind, putting Chinese leadership in a “use it or lose it” situation regarding their nuclear deterrent: if they are not sure that they will be able to use their nuclear systems later, because they fear that they may be disabled or destroyed in an American first strike, Chinese leaders may decide to launch a first strike of their own, while they still control their weapons. It is also possible that Chinese leaders, in the early chaos and high stress of a major conventional war, might mistake a US attack on A2/AD systems for one on China’s nuclear arsenal, leading to nuclear escalation in response to what was intended as only a conventional war.
Even if that scenario were avoided, China might consider any bomb exploding on its home territory to be unacceptable, and such an attack might inflame Chinese nationalism, leading China to escalate what the United States thought of as a limited conflict. It might seem reasonable to the Chinese to retaliate against US territories or even the US mainland.
Fears and suppositions about these escalation scenarios also reduce the credibility of current US guarantees to its allies and increase the risk of strategic miscalculation, making war more likely. The Chinese government may see the danger of escalation as a reason that the United States would back down from intervening to stop Chinese aggression. And as long as US allies’ primary defense strategy is to rely on US forces, their relative defensive weakness could tempt China to launch an attack based on the belief that the United States would self-deter.
Furthermore, to counteract that potential Chinese line of thinking, the United States might itself engage in risky behavior trying to convince the world that it is willing to intervene despite escalation risks. That strong US commitment to constantly reinforce the credibility of its alliance guarantees could itself precipitate crises.37
As long as the United States maintains potent conventional forces capable of attacking deep into China, these capabilities will seem offensive to the Chinese, triggering security dilemma dynamics, regardless of US doctrine. But the problem would be less severe if US forces stayed further from Chinese waters in plans and exercises.38 Shifting US and allied procurement to favor A2/AD systems of their own, which are much more easily identified as defensively oriented, would also help.
Finally, the current US offensive posture risks creating political tension with allies during a future crisis. In their treaties and diplomatic engagements with the United States, Japan, South Korea, and other Asian countries signed on for defense. In the past, these allies have expressed concerns about being dragged into offensive activities by the United States.39 The allies worry that offense poses untenable risks when directed at a nuclear-armed near-peer, like China—something that Washington should recognize, too.
Toward Allied A2/AD
Fortunately, there is an alternative to the costly, ineffective, and dangerous approach currently used to protect America’s Asian allies.40 By meeting allies’ defense needs with clearly defensive weaponry, and without the present forward-deployed, offensively-oriented US force structure, the United States can preserve the territorial integrity of allies while de-escalating tensions in the region.
China’s capability has vastly increased, but its ability to conquer states across water remains limited. If the United States and its allies invest in their own A2/AD capabilities—counterparts to the Chinese capabilities that the US military itself says are extremely effective against US sophisticated weapons—China’s offensive potential will remain limited for many years to come.41
Japan, Korea, and Taiwan are wealthy and technologically proficient states perfectly placed to capitalize on A2/AD technology to defend against any attempted Chinese conquest. As islands or peninsulas that must defend coastlines, East Asian states get special utility out of defensive military technology. These states do not need forces and weapons that mimic the US military. Their forces simply have to make the cost of aggression prohibitive for China and other potential rivals.
Japan already maintains a qualitatively superior force that far outstrips China in submarine, anti-submarine, mining, and missile capabilities, backed up by a sophisticated network of sensors and a geographical position that allows it to straddle major chokepoints for the Chinese navy.42 It has long invested heavily in naval assets to defend its coast. And its GDP per capita remains about four times larger than China’s, providing it considerable capacity to ramp up spending in the event of a massive emergency, like a Chinese campaign of territorial aggression.43
Japan has recently increased its investment in mobile missile systems deployed in the Ryukyu Islands in the East China Sea, a nascent modern A2/AD capability.44 Unfortunately, as MIT experts Eric Heginbotham and Richard Samuels explain, much of Japan’s defense budget is still devoted to a “forward defense strategy” built on fighter aircraft, destroyers, and ground forces.45 Japan has also begun exploring a greater long-range missile strike capability as a means of preemptively threatening North Korea’s ability to launch ballistic missiles or retaliating against China—an investment that potentially looks like offensive defense.46 Finally, Japan has not fully stocked the munitions needed to use its anti-ship, anti-missile, and anti-aircraft systems in an extended campaign.47
Taiwan is more vulnerable.48 As an island, Taiwan has defensive advantages that make conquest difficult, but if China attacked Taiwan, its nearness to the island would enable China’s weapons to enjoy the benefit of home—larger ammunition stores, protection from strikes, better coordination, and short flight times.49 China’s missiles could destroy most fixed targets in Taiwan, including search radars, and seriously impede the operation of Taiwan’s air force.
On the other hand, Taiwan is large enough to drive mobile missile systems around and rugged enough to hide weapons from enemy surveillance and strike systems.50 Taiwan also produces a modern anti-ship missile deployable on trucks or small ships that can likely evade Chinese attacks on fixed targets.
Even while its defense budget has remained flat in recent years, Taiwan has developed, with some US encouragement, a sea-control strategy centered on expensive ships and aircraft meant to win battles with China off and above Taiwan’s shores—mirroring the United States’ offensive-defense posture rather than emphasizing a more prudent defensive defense.51 This strategy is not an efficient way to spend a limited defense budget. Instead, Taiwan could spend its money on relatively inexpensive, high-quality A2/AD capabilities, including ones of indigenous design and manufacture. Taiwan could also significantly expand its deployments of radar decoys and other inexpensive equipment to make it harder for Chinese stand-off weapons to weaken Taiwan's contested zone.
The US military could contribute to Taiwan’s wartime defense through a more operationally defensive posture that would limit exposure to China’s A2/AD systems. In a potential war, seaborne American anti-ship and anti-aircraft systems could cover Taiwan from locations east of the island—and out of China’s A2/AD envelope. More important, in peacetime, the Unites States’ backstop would help ensure that Taiwan, which is much smaller economically than China, would not be overwhelmed in a conventional arms race.
The US military could contribute to Taiwan’s defense through a more operationally defensive posture.
The United States can use its weapons export policies and diplomatic sway over allies to push them to accelerate their adoption of A2/AD technologies. That push would involve shifting money out of programs focused on developing expeditionary or offensive military capability. Instead, the emphasis, which is most pressing for Taiwan, should be on having the allies buy redundant sensor capability that fully exploits decoys and other concealment techniques, robust data fusion capabilities that can maintain the ability to find and target Chinese attackers even when operating under wartime duress, plentiful mobile anti-ship cruise missile and surface-to-air missile systems, and hardened communications systems.
We are not the only defense analysts to push the idea that the United States should encourage Asian allies to improve their A2/AD capabilities. But few have advanced that goal as a way to shift US force posture in Asia, as we do here. One reason to insist on that second step is that it provides a major—perhaps even necessary—incentive for allies to overcome their bureaucratic resistance and make the needed shift in their defense procurement. Moreover, without a major change in its own defense posture, the United States would miss the opportunity to enjoy cost savings and to reduce tensions with China. Indeed, encouraging allied A2/AD investments without changing the way the US military operates could increase US defense spending, as a recent report from the Center for Strategic and Budgetary Assessments advocates.52
Restoring a Traditional Alliance Posture
To encourage US allies to transition to a more defensive defense posture in Asia, the United States should first convey its plans and reasoning to them. US diplomats should explain US interests in the region and the US desire to limit the cost of defending Asian states and to avoid conflict with China. Diplomats should press allies to invest in A2/AD technologies at the expense of force-projection capability. The United States can incentivize allies to make the transition by paying for some of their acquisition of A2/AD-compliant defensive capabilities. The dollars for this will come by reducing funding for US offensive capabilities in East Asia, whose utility will diminish as allies become better able to resist Chinese aggression.
US partners must step up to have a sustainable defense against a potential Chinese threat over the coming decades. This means restoring a more traditional alliance, where the burden is balanced: US power should back up junior partners that have the wealth and capability to hold their own front line, while allies develop operational concepts that do not simply delay until more US troops arrive, but instead try to defend without them.53 To spur change in the actions of Asian partners, the US military should shift away from a forward-defense doctrine that requires spending more and more to operate safely in the teeth of China’s defenses. The goal should be to create a fortified A2/AD zone on both sides of the seas inside Asia’s first island chain—what would be a “no man’s sea” in wartime. To contribute, the US military could develop advanced mobile anti-air and anti-ship missiles, which have not been emphasized in US acquisition planning for decades. These new weapons would be mostly aimed for export to Asian allies.
The goal should be to create a fortified A2/AD zone inside Asia’s first island chain.
Concurrently, the defensive defense approach would reduce the need to invest so much in speculative technologies like hypersonic weapons that are intended to be able to strike targets—notably mobile Chinese A2/AD systems—before they can move out of the way. It would also alleviate some of the burden of developing high-end ship defense systems, freeing up funds to support the allies’ A2/AD defenses.
A Safer World
The great power advantages that the United States enjoyed against all rivals in the post-Cold War world were always bound to erode as other states grew wealthier and sought the ability to avoid being coerced. That is no great tragedy for US security, but the scramble to preserve dominance at all costs could be. By seeking total dominance over all states, even in the skies above them and in their territorial waters, the United States makes needless trouble for itself.
The quest for dominance surrenders the blessings that geography and status quo interests bestow on the United States. It makes the United States pay the growing cost of maintaining an offensive edge as the relative advantages of defense grow. The offensively-oriented dominance approach comes with a growing price tag, diminishing effectiveness, and rising tension with China.
Those ills are avoidable. The United States can secure its allies, partners, and interests in East Asia, even if no one dominates the contested zones between China and its island neighbors. Letting other states bear the cost of being their own first line of defense will not only lower US costs, it will limit tensions in East Asia. Washington should remember that its strategic goals are defensive, and the United States should adjust its military posture to match that reality.