The message from U.S. senior military leaders has been very clear recently: They are very, very worried about a Chinese invasion of Taiwan. For example, retired U.S. Indo-Pacific Command commander Adm. Phil Davidson, his successor, Adm. John Aquilino, and Chairman of the Joint Chiefs of Staff Gen. Mark Milley have all said that China is developing the ability to invade and hold Taiwan in the near future. In turn, debates have emerged over whether it is in America’s interest to defend Taiwan and whether any U.S. ally would assist the United States in such operations. Japan has received a lot of attention because of the importance it plays from an operational standpoint. Not only is it home to the largest U.S. forward presence in the region, it is geographically the closest U.S. ally to Taiwan and possesses the most capable armed forces of any regional ally.
And yet, because Japan has not engaged in combat since 1945 and faces several legal constraints that limit what its Self-Defense Forces can do — as well as a public that is historically pacifist in orientation — one cannot assume that Japan will automatically support any U.S.-led military operation against China in Taiwan’s defense. At the same time, as a trusted U.S. ally that harbors similar strategic concerns of an increasingly aggressive China, the United States should not assume that Japan will do nothing.
The alliance should consider several steps to prepare for possible conflict with China over Taiwan, and ensure its forces are postured to operate together — even for Japan’s defense. Although it is natural to gravitate toward weapon platforms and the best mix of capabilities the allies should have, there may be important discussions to be had in the areas of logistics, decision-making processes, and preparedness. As the allies gear up for a new year filled with senior-level meetings and military exercises, there are six topics that might benefit from extra attention: developing a shared understanding of the alliance’s prior consultation process, clarifying what Japan’s Self-Defense Forces will do to support U.S.-led operations, addressing potential challenges in logistics activities, firming up potential munitions issues, addressing passive defenses and base resiliency, and addressing Japan’s possible role in a Taiwan non-combatant evacuation operation.
Consider them (late) possible New Year’s resolutions: practical means to make a better and stronger alliance in the year ahead.
Developing a Shared Understanding of the Intricacies of Prior Consultation
Should the United States decide to defend Taiwan from China, it will be extremely difficult — if not outright impossible — to prosecute a conflict without access to its bases in Japan. Even delayed access could result in the United States not engaging, or not being positioned in time to successfully engage. Access to U.S. bases — but not Japanese bases — could leave U.S. forces concentrated and vulnerable to devastating attacks.
The issue of access is directly tied to an agreement based on a 1960 exchange of notes that refers to both governments needing to engage in “prior consultation” should the U.S. wish to use its bases in Japan for combat operations not tied to Japan’s defense. Per this agreement, if China does not attack Japan, but the United States wishes to defend Taiwan from a Chinese invasion from its Japanese bases, the United States would need to consult with Japan before initiating any activities. Although there is little disagreement about this requirement, do the allies have a shared agreement (likely not in the public domain) about how the process is expected to play out? In other words, is there a consensus on who is involved in both countries, what decision-making structures must be used to have these conversations, who needs to sign off, and, importantly, how much time the process could take? And are those procedures, processes, and mechanisms practiced not just for a contingency, but for both the transition from steady-state to a contingency and for slow-boil gray zone activities? Or are the allies counting on simplistic assumptions, such as Japan will say “yes” to any U.S. request at a moment’s notice, or that the United States will sit down and engage in lengthy consultations over the issue? Granted, the characterization of these assumptions is overly simplistic, but if Japan is in a situation where it has not been attacked, the prior consultation process could cause tremendous stress on the alliance because it is largely political. As such, the allies could benefit from ensuring they have a shared understanding that results in Japan’s political timelines being in synch with U.S. operational timelines.
Clarifying What Japan’s Armed Forces Will Do to Support U.S.-Led Operations
Beyond issues of base access are questions of Japan’s possible level of involvement. Comments on Taiwan by Japanese politicians have garnered a lot of attention over the past year, leading many to believe Japan will defend Taiwan. For example, much attention was given to then-State Minister for Defense Nakayama Yasuhide referring to Taiwan as a “red line” in December 2020. And in 2021, following a joint statement by senior officials that included a reference to the “importance of peace and stability” in the Taiwan Strait (marking the first such reference to the Taiwan issue in a joint statement since 2011), another joint statement by Prime Minister Suga Yoshihide and President Joe Biden included, for the first time in a summit statement since 1969, bilateral agreement on “the importance of peace and stability across the Taiwan Strait” and “peaceful resolution of cross-strait issues.” Also gaining considerable attention was then-Deputy Prime Minister Asō Tarō who, in his private capacity at a July 2021 political fundraiser, said that “If a major problem occurred on Taiwan, it is not too much to say that it would unmistakably relate to a situation threatening [Japan’s] survival. Japan and the U.S. must defend Taiwan together.” And most recently former prime minister Abe Shinzō said a Taiwan contingency is a Japanese contingency, and therefore a contingency for the alliance.
Comments like these have led some to argue that there has been a fundamental shift in Japan’s Taiwan policy. But as Indiana University’s Adam Liff has argued, these developments do not indicate any major change in Japan’s official posture toward the Taiwan Strait — which has long been ambiguous. While prominent Japanese politicians have become more vocal on the issue, Japan’s position today is not different than it has been previously. Namely, Tokyo wants a peaceful resolution of cross-Strait issues because the peace and stability of the Taiwan Strait matters for Japan’s security. Official government statements are remarkably consistent. Japan is not committed, nor has it ever pledged, to defend Taiwan. Importantly, and often forgotten, Japan has not pledged its commitment for any possible U.S. military operation, including a contingency over Taiwan.
It is understandable that the United States would want Japan’s support in a Taiwan conflict, and there are numerous areas where it may want Japan to assist. As I argued in a 2020 RAND report examining Japan’s potential contributions to an East China Sea contingency, the operational parameters for what Japan can do in specific situations is defined by a suite of Japanese laws passed in 2015. In its most basic terms, if Japan is not attacked and conflict appears somewhat limited, Tokyo may define the situation as only having an “important influence” on Japan’s security. This would limit Japan’s involvement to noncombat, rear-area support roles. If, however, Japan is directly attacked — including attacks on U.S. bases on Japanese territory — or if Tokyo defines the situation as being a threat to Japan’s survival, Japanese involvement could include combat and the use of force.
Contrary to recent commentary that reminded readers of the nuance of these authorities, officials in both countries do have a solid understanding of what is legally permissible in different situations, as well as the range of possible Japanese responses to Chinese aggression. Where the real lack of understanding may exist is the delta between those legal permissions and what Japan is willing to do. Are leaders in both countries confident that there is a shared understanding of what Japan is willing to do, and what the United States wants Japan to do, based on its laws? There are conversations to be had on issues like conducting intelligence, surveillance, and renconaissance; logistical support; air and sea escorts; minesweeping and minelaying; offensive and defensive counter air operations; hunting of submarines and high-value airborne assets; and utilizing Japanese stand-off missiles against an invading force. Despite the existence of the defense guidelines that outline expected roles and missions, it is not clear whether or how Japan will involve itself in a conflict with China, the United States, and Taiwan. If Japan decides that it will get involved, a conversation needs to clarify whether Japan’s support will remain largely tied to Japan’s defense or extend into other objectives. In other words, how far away from Japanese airspace and waters would the Self-Defense Forces operate? What missions will it engage in? And to what extent will those missions connect directly to Japan’s defense? If China’s operational plans are much more developed, defined, and detailed than those of the alliance, the allies may find themselves at a serious disadvantage when conflict starts.
Addressing Potential Challenges in Activities Related to Reception, Staging, Onward Movement, and Integration
Operational support questions tie directly into responsibilities of logistical support in Japan. An often-overlooked but/yet critical fact regarding a regional contingency is that there would be a tremendous amount of movement of U.S. and Japanese forces — not just within Japan, but U.S. forces flowing into Japan from abroad. This, in turn, sets in motion reception, staging, onward movement, and integration activities. Such activities are critical to the successful execution of any operation, as they ensure that forces and supplies move and aggregate on time where needed.
Given their importance, the allies need to ask themselves what organic logistic capabilities are present in Japan if reception, staging, onward movement, and integration activities happened today, where they might fall short, and what civilian capabilities would be required to improve the response. For example, if both U.S. and Japanese forces rely on similar Japanese commercial companies to help transport equipment and supplies throughout the archipelago, have they deconflicted the potential challenges that may arise if both forces make requests on the same companies at the same time? And are these private companies prepared to support complex land transportation movements to support the air and seaport terminal operations that reception, staging, onward movement, and integration activities will require for forces flowing into and through Japan? There are also requirements and timelines the U.S. military need to follow to notify Japanese stakeholders of road movements of military assets. While these are exercised in peacetime, are the allies ready to handle these requests with very little notice in an emergency? For example, given that local officials have a role to play in transportation approvals, have Japanese central government officials and representatives from U.S. Forces Japan engaged in discussions on this issue at the prefectural and municipal levels? And given that any conflict involving Taiwan will largely be over air and sea and require lots of moving parts across the Japanese island chain, are the allies confident their current airlift and sealift capacity is in sufficient quantity and state of readiness relative to the requirements? Finally, are the alliance’s legal documents (i.e., acquisition and cross-servicing agreements) and certifications (i.e., aerial refueling) current to enable the allies to help one another logistically? These documents are, arguably, the glue that ties discussions about reception, staging, onward movement, and integration activities together.
Firming Up Munitions Issues
If Japan does support a U.S.-led operation, even limited to Japan’s defense, one of the most pressing conversations that needs to be had involves munitions. Japan has made significant changes in its posture over the past decade, investing in the development of stand-off missiles and fielding units in the southwest island chain. Recently, Tokyo decided to extend the ranges of its Type 12 anti-ship cruise missile from 200 km to 900 km. During this same time, the United States has been seeking partners to host ground fires. Both activities support the basic fact that in any conflict involving China, munitions of various ranges will play a pivotal role. Regardless of whether we are talking about Japanese or American fires, whether it be for the defense of Japan or for disrupting Chinese operations, a critical question for the alliance will be whether there are sufficient stockpiles of precision guided munitions that will enable Japan to maintain an active defense and permit the United States to prosecute an operation capable of pushing back, or at least withstanding, an onslaught long-enough for follow-on forces to arrive. In other words, do the allies have enough precision guided munitionss in Japan for their respective operations considering China’s capabilities and capacities? This is a critical question: In the United States, budget cuts, along with executing years of operations in Iraq and Afghanistan, and battling groups like the Islamic State, have led to a shortage of munitions. This is not limited to any one service, as evident by shortages in the Army, Navy, and Air Force. And while the munitions used in those wars are not likely the ones needed in a fight over Taiwan, the lack of funding for, and shortage of, munitions remains true.
Current inventory is not the only issue. In a contingency, the United States and Japan would have to be able to rapidly replenish stockpiles through increased production capacity. Yet, as others have noted, in some cases, the lead time for munitions production can be as long as 18 months. While raiding the stockpiles of other combatant commands may be a necessary short-term solution for the United States in a crisis, establishing sufficient production lines should be a priority for both Japan and the United States to ensure they are not overburdening single suppliers of critical weapons. They should also examine whether current replenishment agreements are realistic to meet request and delivery timelines in a crisis. Importantly, if the United States and Japan will be competing for the same precision guided munitions suppliers, is there agreement on how to prioritize? Finally, and perhaps most critically, are the precision guided munitions stockpiles located where the allies need them? Understanding that a Taiwan operation would be heavily reliant on access to supplies in Japan, there is a need to ensure that stockpiles are established to support not just the initial onset of operations, but the subsequent forces flowing into Japan from the continental United States and Hawaii.
Getting Serious About Passive Defenses and Base Resiliency
An often overlooked (and under-funded) issue is that of passive defense capabilities. There is no shortage of analysis that examines what mix of capabilities the United States and/or Japan will need to prevail in a fight against China. Yet, passive defense efforts at U.S. and Japanese bases are vital to sustaining any alliance effort. Given that importance, these capabilities are not always the priority in defense budgets that they could be.
The allies could ask themselves whether their current passive defenses are sufficient to withstand a Chinese attack. This could begin with an examination of whether both allies have sufficiently hardened their defense facilities, such as air bases, munition depots and fuel lines or shelters for their aircraft, like the 20 South Korean-funded, third generation hardened aircraft shelters recently completed on Kunsan Air Base. Relatedly, have the allies proliferated their use of camouflage, concealment and deception capabilities, as China has, to make adversary operations more difficult? They could also examine whether they have sufficient resiliency and redundancy in key elements like communications, satellites, and radars to leverage multiple communication paths, enabling them to function in disruptive operating environments. Similarly, assuming their bases and ports will be made inoperable within the first minutes of an attack, have the allies prepared alternative facilities or dual-use facilities throughout Japan, where they can preposition non-weapons support — such as parts, non-kinetic equipment, or even fuel — in peacetime? And while access to these alternative facilities is granted in the Status of Forces Agreement, understanding that local opposition to military use will be strong, is there consensus on the process for requesting access to these items? None will win the war, but collectively they position the United States and Japan to remain in the fight, thereby not only preventing China from making easy gains, but ensuring support for forces flowing into the theater.
Addressing Japan’s Role in a Taiwan Non-Evacuation Operation
A final issue that could deserve extra attention has to do with Japan’s support for a noncombatant evacuation operation (i.e., a military-assisted departure of civilian noncombatants and nonessential personnel from danger in an overseas country to a designated safe haven). In this situation, the Self-Defense Forces helping to handle flows of civilians fleeing a conflict in Taiwan and entering Japan seems like a natural responsibility, given its non-combat focus. Even if Japan is not involved in supporting U.S. forces, any contingency involving Taiwan will almost certainly demand a noncombatant evacuation operation of some sort. And given Japan’s proximity, the need to have Japan engaged seems apparent.
Noncombatant evacuation operations are extremely challenging — one in Taiwan could be a nightmare given the massive numbers of civilians that may want to evacuate. The allies will need to have clarity on whether they are prepared to assist. At the most foundational level, does Japan have its own established noncombatant evacuation operation doctrine, or do the allies have joint doctrine on this issue, so that they can promote interoperability with their doctrines, terminologies, and rules of engagement? Then there are questions about capacity and capability. In a hypothetical situation, where the United States is helping civilians flee Taiwan, and Japan is tasked with receiving those civilians in a non-combat environment, and where there are no attacks being conducted against Japanese territory, is Japan willing to accept citizens of all countries? What about from Taiwan? And how ready are potential Japanese air ports of debarkation and sea ports of debarkation to handle large influxes of people? Have the allies identified most likely air and sea ports of debarkation, and are they prepositioning critical supplies there? What happens if China initiates kinetic activity against these same targets? Is the Self-Defense Forces ready to conduct a noncombatant evacuation operation in a contested environment? Such a situation also risks Japan having to divert Self-Defense Forces resources away from assisting the noncombatant evacuation operation to defending against the attack. It also raises questions on whether Japan is prepared to accept aircraft or ships that may possibly have been contaminated from weapons of mass destruction.
It is true that the United States enjoys one advantage that China lacks: capable allies. Japan is no exception. But for the United States to enjoy the benefits that come from such a capable ally like Japan — be it base access, rear-area support, or front-line combat support — the alliance could benefit from greater clarity to be cultivated during peacetime. It could very well be that many of the issues examined above have been discussed and agreed upon privately ex ante. In the chance they have not, as the world begins 2022 and the U.S.-Japanese alliance turns its attention to summitry, 2+2 visits, and revisions of strategic documents, alliance managers have a host of practical conversations they could engage in to make a better and stronger alliance in the new year.
Jeffrey W. Hornung is a senior political scientist at the nonprofit, nonpartisan RAND Corporation He specializes in Japanese security and foreign policies, East Asian security issues, and U.S. foreign and defense policies in the Indo-Pacific region, including its alliances.