What’s next for the US-Japan security alliance


    Japanese Prime Minister Yoshihide Suga with U.S. President Joe Biden, April 2021.


    The US-Japan security alliance has been a cornerstone of American foreign policy in East Asia. When the alliance was first established, the US pledged to defend Japan from external forces after the Japanese 1947 constitution was adopted. This arrangement worked because it gave way to the Yoshida Doctrine, a strategy adopted by then Prime Minister Shigeru Yoshida, to ensure Japan can rebuild the country and its economy.

    With tensions heightening due to the Chinese Civil War and Korean War, the Japanese Self-Defense Forces was established in 1954 despite strong opposition due to the presence of Article 9 in the constitution. In 1960, the U.S-Japan Security Treaty was revised to allow for American bases to be established. This was followed by the adoption of the Three Non-Nuclear Principles in 1967. This meant Japan will not possess, produce or introduce nuclear weapons of its own accord in order to avoid being targeted via nuclear attacks. The adoption of the principles meant that Japan relied on the US nuclear umbrella for protection.

    Since the 1990s, Japan has strived to do its part in actively working together with the US on security challenges that affect East Asia as a whole.

    Key Judgement 1

    The US and Japan are highly likely to expand their defense cooperation to confront new security challenges in the region in the next 12 months.

    • The US and Japan began to work together in anti-missile defense after North Korea fired the Taepodong-1 in 1998 [source]. Tokyo reported the results of a feasability study for information gathering satellites to be launched after 2002 [source]. The event was troubling for Japan since the country did not have the resources allocated to conduct anti-ballistic missile surveillance after the US warned Japan about the launch.

    • China’s aggressiveness in its military budget, modernization of the People’s Liberation Army since the 1990s have brought concerns of its superpower ambitions [source].

    • From 2011, the Obama administration brought forth his “Pivot to Asia” policies, which involved building military and political ties with Asia-Pacific countries, including Japan [source]. This was followed by the reestablishment of the Quadrilateral Security Dialogue or the Quad in 2017, which consists of Australia, India, Japan and the US [source].

    • Since 2015, the reinterpretation of Article 9 of the Japanese Constitution has given Tokyo legality to deploy the Japanese Self-Defense Forces and tackle gray zone tactics being used against the country and work alongside friendly countries in collective security situations. This would allow Japan to further contribute in the US-Japan security alliance.

    Key Judgement 2

    Japan is highly likely to contribute more to the security alliance in order to participate further in defensive collective security in the next 12 months

    • The 1st Gulf War brought debate on how Japan should contribute to help the coalition resist Iraq’s invasion of Kuwait. This led to the passing of the International Peace Cooperation Act in June 1992, allowing the JSDF to participate in peacekeeping operations when the first JSDF units were deployed in Cambodia under UNTAC [source].

    • Japanese guidelines passed in 1997 stipulated that the JSDF can operate from domestic soil to surrounding areas in case of an enemy attack [source]. This was perceived by some observers as Japan willing to take the resposbility of defending its territory.

    • In November 2001, the JMSDF deployed ships to the Indian Ocean to provide logistical assistance to American-led military operations in Afghanistan through the Anti-Terrorism Special Measures Law [source]. This was the first time the JSDF was deployed overseas during a military operation.

    • In 2015, Article 9 was given another interpretation to allow JSDF forces to be deployed overseas for collective security purposes while staying within the limits of the clause [source].

    Key Judgment 3

    The US and Japan are highly likely to rebalance cost-sharing with Japan on maintaining United States Force Japans units after President Donald Trump pushed US allies to contribute more to the alliance in the next 12 months

    • It is unclear on the actual cost of maintaining USFJ forces in Japan. This depends on which costs are factored in and is subject to changes.

    • President Biden extended the cost-sharing agreement following previous demands from the Trump administration for Japan to pay up to 8 billion dolllars [source].

    • In December 2021, Prime Minister Fumio Kishida announced an increase of Japanese defense spending. This will start from April 1, 2022 will rise 1.1% to 5.4 trillion yen ($47.18 billion) [source]. This was an indication that Japan is willing to do its part to maintain the alliance from a financial perspective.
    Mark Christian Soo
    Mark Christian Soo
    Mark is a graduate of Nanyang Technological University (NTU) under the S. Rajaratnam School of International Studies (RSIS) with a Master's Degree in Strategic Studies. His research interests focus on Japanese, East and Southeast Asian defense/foreign affairs policy.

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