What is the strategic value of China’s Spratly outposts in the South China Sea? Are they a military asset or liability for Beijing? While they allow China to monitor air and naval traffic in the South China Sea, an emerging consensus in American military circles argues that China’s artificial features are more of a headache for Beijing than for Washington. U.S. Navy and Air Force assets could neutralize the Chinese positions relatively quickly if required.

Gregory Poling disagrees with that assessment. In a recent War on the Rocks article, he concludes that China’s man-made installations could pose a major problem for the U.S. military in the Western Pacific in war time, and could even be used to deny American forces access to the region. Poling argues that “it would be prohibitively costly for the United States to neutralize those outposts during early stages of a conflict.” He warns Washington that dismissing the strategic value of the Spratly outposts would be a mistake.

The arguments that Poling advances are plausible, but not convincing. The conventional wisdom about the Spratly’s still holds true because the reach and capability of the U.S. military to fight its way through China’s island defenses remains robust. The United States, not China, enjoys the benefit of multiple options in the event of a conflict. In contrast, China’s ability to supply the far-flung outposts, amass significant air power on the three largest artificial islands — the Fiery Cross Reef, Subi Reef, and Mischief Reef — and generate and sustain combat air sorties could quickly dwindle in the face of concentrated cruise missile and air strikes against those outposts.

American Options in the South China Sea

China’s outposts in the Spratlys would be difficult for Beijing to defend in a crisis. First, the man-made islands suffer from congestion. Much of the critical infrastructure, such as aircraft shelters and supporting supply and weapons storage, is erected in close proximity, as satellite pictures and aerial photographs clearly demonstrate. Moreover, the limited available real estate creates clear constraints for dispersing air defense systems, equipment, and troops. The tightly packed aircraft shelters offer valuable targets for American planners. Additionally, the very environment on the islands restricts burying critical infrastructure deep underground.

Striking these bases with cruise missiles remains the most plausible U.S. military strategy in the early hours of any conflict. The most realistic military objective for striking these bases would be to degrade their ability to generate air sorties and cut off the outposts’ logistical support from mainland China more than 600 nautical miles away. Another objective would be to keep the Spratlys out of operation until more air power could be mounted against them.

The U.S. Navy and Air Force would need 30–50 cruise missiles per the three largest outposts (or 90–150 cruise missiles total) to accomplish these objectives. This number of cruise missiles would be sufficient to cut each three-kilometer-long runway to roughly 400-meter sections, strike taxiways, quick-reaction alert shelters, and aircraft at open or otherwise known locations. It would also allow American forces to target command, control, and communication nodes, fuel and weapons storage facilities, known air defense sites, as well as logistical facilities and piers. The given number of cruise missiles is inclusive of required redundancy: Two to three missiles are required to ensure successful destruction of key targets like command and control or communication nodes, and three to four missiles may be needed to take out buried or hardened targets.

Air power would be at the forefront of an American approach to seriously degrade China’s ability to mount a substantial defense from the military outposts against follow-on forces. B-2 (or the future B-21) and other stealth aircraft, as well as supporting electronic warfare/electronic attack platforms, would be utilized to penetrate air defenses. The aircraft would drop dozens of precision-guided munitions to take out the defenses that could hinder the Navy’s access to the South China Sea. Air Force and Navy aircraft would expend standoff weapons to crater runways, taxiways, and attack aircraft in shelters or at open. The bases’ supply and storage facilities, as well as the pier infrastructure, would come under heavy attack. American assets would make good use of “stand-off jamming” aircraft, such as the Growler, and “stand-in” decoys and jammers to “blind” and confuse integrated air defences on the bases. Notably, many of these actions would happen in sequence and almost simultaneously. Also, the penetrating munitions the United States would use could undermine or damage the integrity of the artificial islands’ foundation, which has already suffered from erosion.

Poling argues that cruise missile strikes would be ineffective against the Spratlys. He cites the large-scale cruise missile attack against al-Shayrat Air Base in Syria in 2017 — in which the United States launched 59 Tomahawk cruise missiles at the base but failed to stop the base’s operations for any meaningful period of time — as proof that this approach would not work. This argument is based on the fact that “the runway [at al-Sharyat Air Base] was back in operation just a few hours later.” However, none of the 59 Tomahawks launched at the air base targeted the runway. Rather, the United States’ intention was to degrade the Syrian Arab Air Force’s ability to deliver deadly chemical weapons and to signal that such actions do not go without consequences. In line with its objective, Washington targeted aircraft in the open and in hardened aircraft shelters, as well as fuel and ammunition depots and air defenses. The military intention, therefore, was not to destroy the air base completely but to degrade it and convey a message.

The relative dispersion of targets on China’s artificial islands remains well within the range of American cruise missiles. Precision-guided munitions are insensitive to even wide dispersion. If the United States knows of the geographic longitude and latitude of the given targets, it can direct American cruise missiles to those targets regardless of physical dispersion. However, a conventional air strike against an air base with widely dispersed targets would pose a greater challenge. Wide dispersion demands more strike aircraft and attack vectors to cover all intended targets. But this is not a significant problem at the Spratly outposts due to the limited real estate and congestion.

What if China is Able to Deny America Access to the South China Sea?

If America is unable to neutralize China’s Spratly outposts at the outset of a conflict, it can turn to other alternatives. The U.S. Air Force could mount a response of strategic bombers, such as the B-1, B-52, and B-2, laden with sophisticated low-observable cruise missiles. These aircraft could be positioned at U.S. bases in Diego Garcia in the Indian Ocean, Darwin in Australia, or Guam in the Western Pacific Ocean, offering enough ramp-space for the large bombers (see Figure 1). These bases guarantee fast response from a relatively safe distance. By comparison, while U.S. bases in Korea and Japan offer closer proximity, they would likely be targeted by Chinese missile forces in the event of major confrontation. Hawaii’s Hickham Air Force Base could serve as hub for amassing air power and logistics. In the past, the United States has carried out cruise missile strikes in the Middle East with B-52s or B-2s taking-off from the Barksdale AFB — the home for U.S. Air Force Global Strike Command.

Conducting coordinated cruise missile strikes from these distant bases would allow the U.S. Air Force to effectively stop Chinese air operations from the three airfields in the Spratlys, seizing initiative to follow-up with more destructive air strikes or to put focus elsewhere. Carrying between 12–20 advanced cruise missiles each, such as the Tomahawk air-launched cruise missiles (ALCM) or joint air-to-surface standoff missiles (JASSM-ER), U.S. strategic bombers alone have the sufficient range and capacity to degrade or cease adversary air operations in the island outposts.

Gaining access to basing in, for example, the Philippines, Thailand, and Singapore would further benefit the U.S. military’s ability to press in and ultimately destroy Chinese military potential in the Spratlys. Gaining access to basing in Southeast Asian littorals, however, remains an unreliable alternative. As Poling correctly points out, those countries may deny the United States access to their facilities. At the same time, a conflict in the South China Sea would likely involve some of the littoral states in hostilities, directly or indirectly. Against such odds, some of the weaker actors could choose to offer or accept U.S. forces as a concrete security guarantee against Chinese aggression. A shared threat generates alliances. This would open U.S. military access closer to the theatre and allow for greatly increased sortie generation.

Source: Map generated by the author.

To be sure, each U.S. military service has or is devising elaborate plans to ensure continued access to East Asian littorals. The U.S. Air Force, for example, has developed and tested innovative plans to fight its way in, involving rapid and dispersed deployment of multiple 5th-generation fighter elements, supported by a single C-17 or C-130, that stand a better chance to get access closer to the theatre and to challenge an adversary’s air superiority. The Marines’ operational plans include full-length aviation deck amphibious landing ships with flights of F-35Bs, contributing to and supporting the U.S. Navy’s big deck carriers in bringing about dispersed operations and concentrated effects. Again, access to basing in the archipelagic Southeast Asia would make life much easier for the U.S. military, enabling better sustained air operations, but the absence of which would not mean losing the fight.

U.S. warships could be pushed out of the South China Sea by a combination of China’s advanced anti-ship cruise and ballistic missiles, complicating the U.S. Navy’s role in providing the mass (capacity depth) for any cruise missile strike against the Chinese bases in the Spratlys. To maintain an adequate range for Tomahawk land attack missile (TLAM) strikes against the Spratly outposts, U.S. ships could operate from the Sulu or Celebes Seas, as Poling raised. But it is also likely that U.S. Navy ships could launch cruise missile strikes from the Java Sea, Flores Sea, Molucca Sea within the Indonesian archipelago, east of Luzon in the Philippines, or from waters northwest from the Malacca Strait, or east of Sumatra Island (see Figure 2). American submarines could be used to help manned aircraft in cutting Chinese supply efforts to the Spratlys. The more China can amass forces on its Spratly outposts, the more the outposts can rely upon supplies from mainland China.

Source: Map generated by the author.

It’s Hard for China to Maintain a Large Military Footprint on the Spratlys

China’s People’s Liberation Army Air Force (PLAAF) would find it difficult to maintain air supremacy over the South China Sea. China has constructed enough aircraft shelters to base a full regiment (typically 24 aircraft) of fighter aircraft at each of its three largest outposts. PLAAF would need to operate these aircraft from a single runway before any American strike. This reality can easily turn into a serious operational bottleneck during increased flight operations. The RAND Corporation’s 2015 study, “The U.S.-China Military Scorecard,” highlight the PLAAF’s problems in amassing air power over the Spratlys as well as the United States’ ability to bring in decisive air power. In addition, the large number of aircraft on the outposts would be very vulnerable to follow-on attacks due cratered runways. If in the air, however, the aircraft would need to try to make it to Hainan island for landing. Maintaining air superiority over the South China Sea from mainland China does not come easy.

A large military footprint on the Spratlys also creates massive demand for continuous flow of supplies, food, and fuel, virtually all of which would need to be transported by sea from the mainland. The three largest outposts have underground storage spaces for fuel and supplies, but that reserve can last only so long in the face of a U.S. attack. In addition, as casualties mount, repatriation to mainland or replacement of manpower becomes very difficult. Targeting the outposts’ electricity-generation would make matters worse. Based on aerial and satellite pictures, China has not added redundancy to its critical infrastructure on the islands.

To make matters worse for China, Beijing has to take into account possible U.S. submarine presence in the South China Sea when supplying its man-made islands. As some experts see the artificial islands’ defenses forming a “bastion” for Chinese SSBNs, the deep waters also give space for China’s adversaries’ submarines to hide. China has made headway in developing anti-submarine warfare capabilities, but this area remains one of its burgeoning navy’s greatest weaknesses. Forming an undersea blockade to attrite Chinese supplies to the outposts thus poses a real and present danger to Chinese defense planners.

The true military value of the outposts, as Poling rightly alluded to, is in their ability to generate an unmatched situational awareness in air and sea in the South China Sea, enabling China’s military to monitor all movement in and out the South China Sea. This can be further supported by innovative uses of China’s maritime militia observing movements at sea where sensors cannot reach. It has also become clear that China has gained escalation dominance in the South China Sea in most situations short of war. This de facto control of the South China Sea gives China an important advantage over its neighbours in helping sustain and expand the reach and presence of its maritime forces in the region. The man-made features would be particularly useful for Beijing in any conflict between China and its smaller Southeast Asian neighbours that do not possess America’s military might.

The Big Picture

China’s outposts in the Spratlys are a strategic liability for Beijing. They are hard to defend, and the United States has a number of options to attack them in a conflict. The American military retains its ability to degrade Chinese forces on the islands and to create a permissive environment for a further military push against Chinese assets in the South China Sea. There is no immediate military need to destroy the outposts completely, but rather to diminish their ability to bring about their intended military effects.

There is only so much that China can do to further bolster the man-made islands’ defenses. Any new addition of capabilities also creates further demands for supply and support. Ultimately, the offense — in this case the United States — should always have the advantage when it comes to the Spratlys. U.S. tested conventionally armed intermediate range ballistic missile over the Pacific in December 2019 – once banned under the intermediate-range nuclear forces treaty (INF) – a system that offer offensive advantages if deployed in the region. Additionally, Navy, Marines, Army, and Air Force are all working at breakneck speed to field a rapidly deployable hypersonic missile capability to frontline forces as early as 2021 or 2023. These new weapons will provide Washington with additional military options going forward. Any use of nuclear weapons against the Spratly outposts would not be advised and is an overkill. At the same time, nuclear weapons should deter a full-blown escalation between China and the United States. At the same time, as Sino-U.S. tensions intensify, Washington should not lose sight of simultaneous developments elsewhere in the vast Indo-Pacific. There is no space for complacency when it comes to the competition with China.

Olli Pekka Suorsa, Ph.D., is a research fellow at the Institute of Defense and Strategic Studies, S. Rajaratnam School of International Studies, Singapore.

Image: Air Force (Photo by Staff Sgt. Joshua Smoot)