No, Japan Will Not Defend Taiwan
Whatever the Kishida administration might want, there are still strong domestic constraints to the country taking part in any conflict in the Taiwan Strait.
Japan aims to play a greater security role under Prime Minister Kishida Fumio. On December 16, 2022, the Kishida administration approved three new strategic documents: the National Security Strategy, the National Defense Strategy, and the Defense Buildup Program. Under the new strategy, Japan aims to double the defense budget from the current level of roughly 1 percent of GDP to 2 percent of GDP within five years. In addition, Japan decided to purchase cruise missiles from the United States to develop a “counterstrike” capability, a clever wordplay that in reality means “preemptive strike” capability.
Despite these changes, is Japan ready to take on a more active role in regional security? One major test for Japan’s new policy is the ongoing tension in the Taiwan Strait.
Many unofficial voices from Japan advocate for Tokyo to provide stronger support for Taiwan. After his resignation, former Prime Minister Abe Shinzo boldly claimed that “a crisis for Taiwan is a crisis for Japan.”
Abe’s rhetoric has been continued by politicians within the ruling Liberal Democratic Party (LDP). During a speech in Taiwan in summer 2023, former Prime Minister and current LDP Vice President Aso Taro declared that Japan, Taiwan, and the United States must have “the determination to fight” when facing China’s growing military threats. In another speech in January 2024, Aso declared that a Taiwan crisis constitutes “a threat of national existence” for Japan.
“A threat of national existence” is one of the three conditions that must be met for the Japanese government to exercise collective self-defense When “another country closely related to Japan” faces an armed attack that “poses a clear and imminent danger to the existence” of Japan, the government has the authority to exercise collective self-defense. In other words, Aso was suggesting that Japan could send its Self-Defense Forces (SDF) to defend Taiwan in the event of an attack from China.
Many people in Taiwan believe these comments from Aso and the late Abe are a reflection of the Japan government’s official policy. In a March 2022 poll conducted by the Taiwanese Public Opinion Foundation, 43.1 percent of respondents believed that Japan would defend Taiwan in the event of an invasion by China. In comparison, only 42.8 percent believed that the United States would defend Taiwan. It is shocking to see that more people in Taiwan believe Japan, a country constitutionally restrained from fighting a war, will defend Taiwan than the United States, the only country that has declared its commitment to defend Taiwan under certain conditions.
In addition, 60 percent of respondents believed that Japan would provide necessary aid, including diplomatic, economic, and military aid, to Taiwan when facing an invasion from China. This is not just the opinion of regular people in Taiwan; even government officials shared this belief. The Taiwanese Ministry of Foreign Affairs issued a special statement of appreciation thanking Aso for his comment. When visiting Taiwan’s Ministry of Foreign Affairs, a diplomat from the Taiwan-Japan Relations Association quoted Aso and said Japan would fight with Taiwan during a Taiwan Strait war with China.
Before analyzing the validity of Aso’s recent remarks, it is important to realize that he is not a credible source. Despite his high position within the LDP and his role as former prime minister, Aso does not represent Japanese official policy. When asked about the comment, a Japanese Ministry of Foreign Affairs official commented that Aso’s statements only represent his personal view and refused to further elaborate on the connection between Aso’s comments and Japan’s official position. His attempt to distance the ministry from Aso’s comment is telling.
Aso Taro is known as “the King of Absurd Comments.” For example, when commenting on Japan’s demographic problem in 2019, Aso claimed that the problem arose from women “not having children.” When asked why the number of deaths from COVID-19 in Japan is lower than in Western countries, Aso answeredthat “the level of civility among people is different,” implying Japanese people are more “civilized” than people in the West. In his most recent misspeaking scandal, Aso openly disparaged Foreign Minister Kamikawa Yoko’s appearance. In a public speech, Aso called Kamikawa “that old woman” and commented, “I won’t say she is beautiful.”
Given Aso’s track record of making thoughtless remarks – most of which he eventually walked back in the face of public backlash – it is highly possible that Aso’s Taiwan comments are nothing more than his trademark “absurd comments.”
What factors will determine Japan’s response to a potential Taiwan Strait crisis?
The first challenge Japan will face is whether war in the Taiwan Strait triggers Japan’s right to collective self-defense. The National Diet must approve the situation as “a threat to national existence” and grant the prime minister and the Defense Ministry the right to use force. However, such approval is difficult to acquire. Opposition parties – which voted against the right of collective self-defense in the first place – are likely to oppose Japan sending the SDF into combat. Even Komeito, the LDP’s ruling partner, might not support sending forces to Taiwan due to its long-time pacifist position.
Even if the first condition is met, the other two of the three conditions for collective self-defense – “there is no other means to counter the threat” and “the use of force in self-defense is limited to the minimum necessary level” – are extremely vague. It will take more debates in the Diet to establish the guidelines for dispatching the SDF.
Meanwhile, China’s military plans for Taiwan center on fighting a “lightning war,” aiming to take Taiwan within weeks, even days. The political debate within the Diet is likely to delay Japan’s response. In the worst situation, Japan will find its response “too little, too late” due to domestic political disputes.
In addition, the public opposes Japanese involvement in a potential Taiwan conflict. According to a 2022 national survey, only 22.5 percent of Japanese respondents supported the SDF fighting side-by-side with the United States against the People’s Liberation Army in a Taiwan conflict, while 74.2 percent opposed it. In addition, only 44.8 percent percent supported the SDF performing a non-combat supportive role for the U.S. military, while 51.1 percent were against that as well.
What is more alarming for the Japan-U.S. alliance is that only about half of the respondents supported the American use of U.S. military bases in Japan during a Taiwan Strait conflict, while the other half were in favor of shutting down U.S. military bases for American military use – even at the risk of obstructing the Japan-U.S. security alliance.
The public also does not want to see the SDF involved in any form of combat. After the U.S. invasion of Iraq in 2003, the Koizumi administration sent the SDF to Iraq, the first SDF operation abroad outside of a United Nations Peacekeeping Operation. However, the SDF was tasked with construction and post-war relief operations, and its personnel were prohibited from firing even if enemies attacked them. As a result, Australian and Dutch troops had to protect SDF members during their operation, which led to complaints about “babysitting the Japanese.”
It was widely believed at the time that if the SDF faced casualties or fired at the enemy, the popular Koizumi Cabinet would collapse overnight. In 2006, a Ministry of Defense official who served as a civilian adviser to the commander of the SDF troops operating in Iraq described the attitude of Japanese people: “Japanese people do not want to see the SDF pointing guns at the people of other countries in foreign lands. The Japanese public supported SDF activities in Iraq because they were essentially in Iraq to repair roads, hospitals, and schools.”
The overwhelming public opposition to Japanese military involvement and the divide over whether Japan should honor its alliance with the United States during a potential Taiwan Strait conflict is significant. Opposition parties could seize the anti-war populism to stall approval to dispatch the SDF.
The LDP’s political standing at home could prove decisive. During times of political turmoil, the LDP relies on public opinion more, and it does not dare to make decisions that contradict the public wishes. For example, during Prime Minister Kaifu Toshiki’s term (1989-1991), the LDP faced a series of high-profile scandals, including the Recruit Scandal and Prime Minister Uno Sosuke’s sex scandal. Attempting to regain public support, the Kaifu administration could not contradict the public opposition and unilaterally deploy the SDF overseas during the 1990-1991 Gulf War. Today, the LDP faces the biggest scandal in three decades amid public anger about political slush funds. That would similarly constrain LDP action in the event of a Taiwan conflict.
Another challenge is that the institutional infrastructure of the SDF does not support Japan’s participation in a military conflict. The SDF has an extremely low appetite for casualties. In a poll conducted among SDF members in the mid-2000s, over 50 percent of officers believed that more than 100 deaths in combat situations surrounding Japan would be unacceptable. The situation is unlikely to change today.
According to a Ministry of Defense official, while Japanese SDF members understand their duty to defend Japan, many have not contextualized it. For many Japanese, the primary role of the SDF is not combat but humanitarian aid. During the 2011 earthquake, for example, the SDF performed admirably in post-disaster aid and further cemented this public image. In fact, many service members joined the SDF to help people, the Ministry of Defense official admitted, and whether they are mentally prepared to enter combat is unknown.
Besides, the Japanese constitution does not recognize the SDF’s role as a military force. Hence, Japan does not have a court martial system. Legally, SDF soldiers killing enemies on the battlefield could be subject to domestic trials.
The friendship between Japan and Taiwan is real and valid. In the National Security Strategy, Japan identifies Taiwan as “an extremely important partner and a precious friend.” Even in Hokkaido, the part of Japan farthest away from the Taiwan Strait, one can still see signs promoting “Taiwan-Japan friendship.” However, institutional challenges and the lack of public support constrain Japan from militarily supporting Taiwan in any cross-strait war. A misunderstanding of Japan’s political situation could be dangerous for Taiwanese policymakers.
Authorsst Author
Zhuoran Li
Zhuoran Li is a Ph.D. candidate in China studies and a research assistant at the School of Advanced International Studies (SAIS), Johns Hopkins University. His work has been featured in The Diplomat and the National Interest, and he has appeared on Vox News.