Papers in the JIIA Strategic Commentary Series are prepared mainly by JIIA research fellows to provide comments and policy-oriented analyses of significant international affairs issues in a readily comprehensible and timely manner.

A summit meeting between Prime Minister Yoshihide Suga and President Joe Biden was held on April 16, 2021, followed by a joint statement. In the statement, for the first time in the 52 years since 1969, the importance of the security of the Taiwan Strait was emphasized by the leaders of Japan and the United States, confirming that both countries are increasingly concerned about the current situation regarding Taiwan. According to a poll conducted by Nikkei Inc. after the summit, 50% of the Japanese public considered the U.S.-Japan summit itself as "positive" (32% "negative"), and 74% of the respondents "agreed" that Japan should be involved in stabilizing the Taiwan Strait, while only 13% "disagreed." These figures were received with some surprise by experts.

This paper will analyze these changes in Japan's perception of Taiwan, and then examine the issues that Japan should address in the future following the recent Japan-U.S. joint statement.

The Taiwan Clause Half a Century Ago

This is the first time in half a century that the leaders of Japan and the United States have confirmed the importance of security in the Taiwan Strait, but the environment surrounding Taiwan is very different today than it was in 1969. When Prime Minister Eisaku Sato visited Washington in November of that year, he and President Richard Nixon issued a joint statement on the reversion of Okinawa, describing the security of Korea as "essential" to Japan's own security and the maintenance of peace and security in the "Taiwan area" as "a most important factor" to Japan's security; they were referred to as the "Korea clause" and the "Taiwan clause" respectively. This implied that, in exchange for the return of Okinawa, the Japanese side would guarantee flexible operation of U.S. bases in Japan in the event of a Far East emergency based on Article XI of the Japan-U.S. Security Treaty.

However, the Japanese side did not treat the Korea clause and the Taiwan clause in the same way. At a press conference following the release of the joint statement, Prime Minister Sato said that an armed attack on South Korea would have an important impact on Japan and that Japan would promptly adopt a positive posture in prior consultations on the use of U.S. bases in Japan. On the other hand, while he appreciated the U.S.'s defense obligations in emergencies involving Taiwan, Sato said, "Fortunately, such a situation is not foreseeable," indicating his recognition that there was no imminent threat to Taiwan.

This was a natural recognition given that the military balance between the U.S. and China at the time was overwhelmingly in favor of the U.S. In addition, it reflected the growing momentum in Japan for normalization of relations with China. In fact, with the subsequent rapprochement between Washington and Beijing, the Japanese government tried to pretend that the Taiwan clause did not exist, saying that "the situation had changed." Prime Minister Kakuei Tanaka, upon returning from Beijing in 1972 after finalizing the normalization between Tokyo and Beijing, stated that the Taiwan clause had become merely a subject of "academic" study. Subsequently, China and the United States formed an "implicit alliance" against the Soviet Union, and Taiwan was no longer discussed in relation to Japan's security.

However, with the end of the Cold War, the Taiwan issue once again gained attention as a legacy of the Cold War. The process of redefining the Japan-U.S. alliance, which had been "adrift" after the Cold War, was directly triggered by the North Korean nuclear crisis, but the Taiwan Strait crisis of 1996 reaffirmed that a Taiwanese contingency could be included among "situations in areas surrounding Japan." Nevertheless, the U.S.-China military balance still favored the United States, and the Taiwan Strait crisis was settled by the deployment of two U.S. carrier strike groups to the waters near the Taiwan Strait. On the other hand, its humiliation at that time led China to make all-out efforts to develop the capability to prevent U.S. military intervention in a Taiwan contingency.

At the 2005 Japan-U.S. "Two Plus Two" meeting, one of the shared strategic goals was to "encourage the peaceful resolution of issues concerning the Taiwan Strait through dialogue." This was in response to China's enactment of the Anti-secession Law authorizing the use of force to prevent Taiwan's independence just as the Democratic Progressive Party (DPP) administration under Chen Shui-bian in Taiwan appeared to be moving toward independence. However, when the Kuomintang's Ma Ying-jeou administration came to power, relations between China and Taiwan improved dramatically, and there was instead concern that Taiwan might be peacefully incorporated into China.

Background of the New Taiwan Clause

However, with the 2016 inauguration of the Tsai Ing-wen administration, which refused to acknowledge that China and Taiwan had affirmed the one-China principle in 1992, China began to increase its diplomatic, economic and military pressure on Taiwan through, among other means, a circumnavigation of Taiwan by aircraft carriers and bombers. In 2019, President Xi Jinping said that Taiwan's reunification was essential for the "great rejuvenation of the Chinese nation" and called on Taiwan to reunify under "one country, two systems", reaffirming that he would not rule out the use of force against any move toward independence. As "one country, two systems" was ignored in Hong Kong and after President Tsai Ing-wen, who rejected this idea of "one country, two systems", was re-elected in 2020, Chinese military aircraft started to repeatedly cross the median line of the Taiwan Strait to enter Taiwan's air defense identification zone, further raising concerns about unforeseen events.

During this period, China increased its counter-intervention capability, and the United States became increasingly wary of what it termed an "anti-access/area-denial" (A2/AD) capability. In addition to developing anti-ship ballistic missiles known as "carrier killers" and introducing quieter submarines, China also began operating aircraft carriers in earnest and developing and deploying anti-satellite, cyber-attack, electronic warfare and other asymmetric capabilities. In the South China Sea, the militarization of artificial islands has progressed, and the deployment of hypersonic glide weapons, which are considered difficult to intercept, has been reported. In addition, China has been modernizing its nuclear forces and improving its power projection capabilities by introducing large amphibious assault ships.

At a Senate hearing in March 2021, Phil Davidson, the soon-retiring commander of the Indo-Pacific Command, testified that the military balance in the Western Pacific was becoming even more unfavorable to the U.S. military as he used charts to illustrate the People's Liberation Army's growing capabilities over the past two decades. Then, referring to the possibility of a Chinese invasion of Taiwan "within the next six years" amid growing nationalism in China, he argued that it would be worth discussing the "strategic ambiguity" of the U.S.'s obligation to defend Taiwan, including its review. Reportedly, the U.S. military is increasingly losing ground to the People's Liberation Army in tabletop exercises, and the commander's remarks reflect a growing sense of emergency within the U.S. military.

In Japan, meanwhile, there is rising concern that a Taiwan contingency will become a Japan contingency because of the geographical proximity between Taiwan and Okinawa; if China were to launch an armed invasion of Taiwan, an attack on U.S. military bases in Okinawa would be expected as well. In 2017, Japan and the U.S. reportedly drew up a joint operation plan for a contingency on the Korean Peninsula, but no joint operation plan for a contingency in Taiwan has reportedly been drawn up. However, for Japan and the Japan-U.S. alliance, the Taiwan contingency is no longer a subject of academic study but is now a realistic policy issue.

It was against this background that the Suga-Biden joint statement included the new Taiwan clause. According to media reports, the U.S. side requested that Taiwan be mentioned in the joint statement and the Japanese side reluctantly agreed, but there is no discrepancy between the two countries in terms of their understanding of the situation surrounding Taiwan. It is important to note that the new Taiwan clause is an issue that should be considered based on Article V of the Japan-U.S. Security Treaty, which is about bilateral cooperation in the event of a Japanese emergency, rather than Article VI.

Issues for Japan to Address

So, how should Japan tackle this issue? First, Japan should contribute indirectly to the defense of Taiwan by steadily developing a multi-domain joint defense force and at the same time further deepening Japan-U.S. defense cooperation. To this end, Japan and the United States need to draw up joint operational plans not only for the defense of the Senkaku Islands and other southwestern islands but also for a contingency in Taiwan, followed by joint training and exercises based on this plan. In addition, effectively dealing with the more than 1,200 missiles that China possesses will require both Japan and the United States to increase their missile defense capabilities and deploy medium-range missiles on the first island chain. This will entail difficult coordination with local communities in Japan, but it is an unavoidable issue for improving deterrence and response capabilities.

Next, Japan should also consider how to cooperate with Taiwan on defense. Under the one-China policy, direct defense cooperation is constrained but the People's Liberation Army's operations in the Bashi Strait are a common concern, and Japan should seek information sharing either directly or indirectly through the United States. In addition, people-to-people exchanges should be expanded, for example, using track II platforms. Furthermore, consideration should be given to utilizing multilateral frameworks such as the U.S.-sponsored RIMPAC and the Japan-U.S.-India Malabar Naval Exercise to deepen cooperation between Taiwan's military and Japan's Self-Defense Forces.

At the same time, in order to maintain peace and stability in the Taiwan Strait, it is necessary to modify the military balance between China and Taiwan now overwhelmingly in China's favor. The United States provides arms to Taiwan under the Taiwan Relations Act. The previous Trump administration continued to support Taiwan's defense efforts by proactively selling drones, large guided mines, anti-ship missiles, self-propelled howitzers and anti-tank missiles, as well as extending the life of PAC-3 interceptor missiles. The Biden administration is also expected to support Taiwan's defense efforts. Japan needs to develop its legal foundation considering the current situation in which the United States and European countries are providing arms to Taiwan even under their one-China policies.

The tension in the Taiwan Strait is rising as China strengthens its rule based on nationalism, and the Japan-U.S. alliance is about to face its greatest test in 70 years. China's economic power is expected to catch up with that of the United States by 2030, and the bilateral military balance will be more favorable to China. It will become increasingly difficult for the United States to face China's military challenge alone. This is why Japan and the United States need to enhance their defense and deterrent capabilities under an appropriate division of labor to deter armed attacks on the Senkaku Islands and Taiwan.

The joint statement between the two leaders is only the beginning. The second U.S.-Japan 2+2 meeting within one year is expected to take place before the end of 2021, in order to review concrete progress of their cooperation. With nearly 80 percent of public opinion supporting the new Taiwan clause, Japan should urgently begin to revise its National Security Strategy formulated in 2013, strengthen the Japan-U.S. alliance, and contribute to peace and stability in the Taiwan Strait.

This is an English translation of the original Japanese version published on May 11, 2021.