From April to May 2021, the U.S. Air Force (USAF) conducted a second exercise to test the Agile Combat Employment (ACE) concept and also committed to training units to implement ACE (U.S. Air Force, May 15; Air Combat Command, May 12). ACE is the method by which the USAF intends to counteract the capabilities of adversaries such as Russia and the People’s Republic of China (PRC) to strike its airbases and, ultimately, deny the USAF access to theaters of operations along their peripheries. These are generally referred to as “anti-access and area denial” capabilities. ACE, in combination with similar efforts by other U.S. military services, aims to improve America’s military advantage and its deterrence capability against Moscow’s and Beijing’s increasing aggression in Europe and East Asia.
It is important to understand how America’s adversaries are perceiving and planning to counteract ACE. This article analyzes the People’s Liberation Army’s (PLA) publicly available assessment of ACE. Although there is a dearth of sources, the available information shows that the PLA perceives exploitable weaknesses in ACE.
The Imperative of ACE
Because air power is dependent on airfields, the USAF’s small network of airbases is its greatest weakness in the Asia-Pacific. The USAF has six bases in the region from which to project airpower: Osan and Kunsan Air Bases in the Republic of Korea (ROK); Misawa, Yokota, and Kadena Air Bases in Japan; and Anderson Air Base on Guam. These bases will also function as primary logistical hubs for operations in the early phases of a war. In the event of a Sino-American war over Taiwan, for example, it is unlikely that Seoul would allow U.S. forces to engage in hostilities with the PRC from bases in the ROK, and Anderson Air Base is approximately 1,700 miles from Taiwan, more than four times the average fighter aircraft’s combat radius. Therefore, the PLA would only have to concentrate strikes on the three airbases in Japan to incapacitate the USAF. Each of those bases—and even Anderson Air Base—is within range of the PLA’s conventional cruise and ballistic missiles.
ACE is an attempt to resolve this predicament principally through dispersed deployment. It involves a network of airfields arranged in “clusters” in which major bases, such as the six bases above, will function as hubs, and a combination of smaller military airfields, civilian airports, and even temporary airstrips will function as spokes. Materiel pre-positioned at these spokes in what are called Regional Base Cluster Pre-positioning (RBCP) kits will ensure that they can independently sustain operations for a period of time. The USAF only intends to disperse units in the early phases of a war—long enough to eliminate the threats to its major bases or at least to absorb the hail of missiles. By presenting many more targets, the USAF should prevent the PLA from achieving significant effects by concentrating strikes on a small number of airbases.
Finding PLA Assessments of ACE
The search for PLA sources concerning ACE was limited to official media that is publicly available on the Internet. It is worth noting that the PLA media’s publication or broadcasting of an idea does not necessarily make it orthodoxy: the nature of the topic, the column or segment, and the status of the author or speaker must all be considered when assessing authoritativeness. At the same time, PLA media are not open forums, and commentary never expresses heterodox or “incorrect” views. Only views that are judged to be worthy of consideration are published.
PLA Assessment of ACE
Only one source assessing (not mentioning or explaining) ACE was found. This was a July 2020 article published in the regular Global Military Affairs section of Liberation Army News (解放军报, jiefang jun bao), the mouthpiece of the Central Military Commission (CMC) that exercises administrative and operational control over the PLA and is roughly equivalent to the U.S. Department of Defense. The article’s three coauthors, Yuan Yi (袁艺), Xu Wenhua (徐文华), and Xu Jinhua (徐金华), are identified as belonging to the War Research Institute of the Academy of Military Science (军事科学院战争研究院, junshi kexue yuan zhanzheng yanjiuyuan), which is the PLA’s specialized institution for “researching war and designing war,” i.e., researching warfare, developing operational concepts and doctrine, and designing operations (Liberation Army News, May 14, 2019; Liberation Army News, June 21, 2018). PLA media infrequently indicate author affiliation, so the fact that the authors were identified as belonging to the War Research Institute could indicate that the article reflects institutional opinion. Regardless, because the War Research Institute is likely responsible for devising the strategy and designing the operations that would counteract ACE, the views of its members—particularly as published in the PLA’s mouthpiece—are likely to influence that strategy and those operations.
Yuan, Xu, and Xu correctly characterize the purpose of ACE to be reducing the risk to the USAF’s operations from adversaries’ “medium- and long-range” strikes through temporary and dispersed deployment, effectively making it more difficult for an adversary to “control the air by land” (Liberation Army News, July 2, 2020). It is noteworthy that the authors did not criticize the distributed employment idea underlying ACE, which likely indicates that they regard it as sound.
The authors raise three weaknesses of ACE. First, they remark that regional countries might not permit the USAF to use their airfields for military operations due to the risk of consequent counterstrikes, writing, “It is uncertain whether even so-called ‘reliable’ allies [almost certainly a reference to Japan] will consent or not to American military aircraft’s taking off from within their borders to go attack a third country with which they themselves are not in direct conflict,” (Liberation Army News, July 2, 2020). Second, they argue that ACE will not reduce the USAF’s reliance on permanent bases. Because both the number of fighters and sorties that a RBCP kit can sustain and the length of time that it can do so is “limited,” units at small, temporary bases will ultimately rely on support from large, permanent bases that will retain a “nodal function,” and that “once an adversary paralyzes those large bases, then the effect of small, temporary bases will be greatly reduced” (Liberation Army News, July 2, 2020). Third, they suggest that an adversary could counteract ACE by shortening the time necessary to complete its kill chain: “If an adversary forward-deploys its maritime and aerial reconnaissance and strike platforms, […] then it is completely possible for the adversary to grasp the brief window [of opportunity] during which American aircraft have landed at small, frontline airfields to conduct precision strikes” (Liberation Army News, July 2, 2020). The authors reason that because the small, temporary airfields will “basically” have “zero” defenses, once an adversary locates American aircraft, “all that will remain for them is to suffer a beating” (Liberation Army News, July 2, 2020).
Analysis of the PLA Assessment of ACE
These three weaknesses can be analyzed in the order of their validity and their importance. First, like ACE itself, shortening one’s kill chain is easier said than done. Maritime and aerial reconnaissance and strike platforms lack the persistence to detect all the movements of the USAF’s units, and it is overly optimistic to think that they can be forward-deployed without being exposed to attack. While it is true that the point defense of many more airfields would be a challenge—and often probably impossible—dispersed and dynamic deployment is itself a defensive measure that will confound an adversary’s intelligence, surveillance, and reconnaissance, which should make point defense less necessary. It is worth mentioning that the PLA may not have to rely on its own surveillance and reconnaissance systems. Aviation enthusiasts and anti-base activists, such as Rimpeace in Japan, may reveal enough information before or while units are dispersed, enabling the PLA to formulate a smaller set of targets on which to concentrate strikes and thereby achieve greater effects. To compensate, the USAF intends to shift units among the spokes faster than an adversary can complete its kill chain.
The authors’ remarks concerning logistics are basically correct. Logistics networks cannot avoid having critical nodes, i.e., ports and depots. It is theoretically possible to disperse the USAF’s logistics network across the Pacific Ocean, thereby placing most critical nodes outside the range of the PLA’s conventional ballistic missiles. However, men and materiel can only be transported across the ocean by air or by sea, and the ocean presents few options for storage and transshipment. Moreover, transporting supplies directly to each spoke would severely strain the USAF’s airlift units. Of course, the USAF does not intend to disperse its units indefinitely; the plan is for the RBCP kits and some other in-theater assets to enable units to operate until they can be safely resupplied through the more efficient, established logistics network.
The challenge for the USAF is to survive the PLA’s attacks and to eliminate the threats to its major bases before its supplies run out; the challenge for the PLA is to preserve its missile launch units and conserve its missiles for as long as it takes for the USAF’s dispersed units to exhaust their supplies. All of the PLA’s conventional ballistic missile systems are road-mobile, so the PLA’s launch units will be employed as agilely as the USAF’s units in order to increase their survivability. It would be prudent for the USAF to build redundant, concealed depots in the theater of operations from which materiel can be transported to each spoke over shorter distances by land. The USAF would thereby extend the time that its units can operate while dispersed across the theater. However, building additional military facilities in an allied country would require the assent of that country’s government, which leads to the topic of allied cooperation.
The authors implicitly, and correctly, identify regional allies—particularly Japan—as the U.S. armed forces’ center of gravity in any war in East Asia, raising the very real possibility that ACE can be defeated principally through political or diplomatic, rather than military, means. For that very reason, it is crucial for the USAF to be able to disperse its units across multiple locations in multiple countries. Doing so would frustrate any effort by Beijing to diplomatically thwart U.S. intervention in the region and it would complicate PLA plans to invade Taiwan. The more countries that host the USAF’s dispersed units, the greater the dilemma that Beijing will face: On the one hand, should Beijing attack the USAF’s units that are stationed in third countries, it risks the possibility that these countries would consequently be drawn into a conflict over Taiwan on America’s side. On the other hand, if Beijing disregards those units to decrease the likelihood that those countries would participate directly in the defense of Taiwan, does it effectively give the USAF a free hand to operate from those countries? Because the U.S. already has military alliances with Japan, the ROK, and the Philippines, which are all close to Taiwan, it would be ideal if the USAF could disperse its units among airfields in these three countries. But Washington, not the USAF, will have to convince Tokyo, Seoul, and Manila that their interests are better served in the current regional order, not in the one that will result from America’s failure to defend Taiwan from annexation.
All in all, the PLA’s first public assessment of ACE is valid. Its authors overstated the ease of detecting and striking dispersed, constantly moving units. They are correct, however, that supplying those units beyond a relatively brief period of time will be extremely difficult, and that critical nodes will inevitably continue to exist in the USAF’s logistics network. It will not be impossible for the PLA to counteract ACE by preserving its missile launch units and concentrating strikes against the USAF’s logistics network instead of combat units.
It is advisable for the USAF to increase the redundancy of depots in the theater of operations so that the spokes of each regional cluster can be resupplied over shorter lines of communication, extending the time that the USAF’s combat units can operate while dispersed across the theater. The authors are also correct that ACE depends entirely on the cooperation of American allies, so the most effective strategy for counteracting ACE will be diplomatic, not military. Just as ACE will be key to maintaining our military advantage over the PLA and deterring the PRC from invading Taiwan, diplomacy and resolute foreign policy will be key to ensuring ACE’s success. There is strength in numbers. A multilateral coalition whose purpose is to defend Taiwan will do as much to deter Beijing as it would to ensure the effective implementation of ACE.
Derek Solen is a senior researcher at the U.S. Air Force’s China Aerospace Studies Institute. He was a civilian intelligence specialist in the U.S. Army. The views expressed are his own and do not reflect the official policy or position of the U.S. Air Force, the U.S. Department of Defense, or the U.S. government.
 It is tempting to interpret “war design” as “operational design,” but the PLA’s war design seems to be more extensive, even encompassing national military strategy. In the particular case of the PLA, the War Research Institute’s role is likely limited to operational design because planning joint operations is the responsibility of the Central Military Commission’s Joint Staff Department (Liberation Army News, June 21, 2018).
 Liberation Army News recently published an article that argued, based on the same premise underlying ACE, that distributed employment is a “basic requirement” for ensuring survivability in future wars (Liberation Army News, May 18, 2021).