Security Treaty Between the United States and Japan

What Happened

On September 8, 1951, representatives of Japan and the United States signed the Security Treaty Between the United States and Japan in San Francisco, California. The signing took place alongside the Treaty of San Francisco, the peace agreement that formally ended the Second World War in Asia. The security treaty went into effect on April 28, 1952, the same day the peace treaty took effect and the Allied Occupation of Japan came to an end.

The treaty was short, running to only five articles. It permitted the United States to keep military bases on Japanese soil after the Occupation ended, and it barred Japan from granting bases or military rights to any third country without American consent. It allowed the United States to use forces stationed in Japan without prior consultation with the Japanese government, and it contained no clause obliging the United States to defend Japan if Japan were attacked. It also set no expiration date and described no precise mechanism for ending it.

The United States Senate ratified the treaty on March 20, 1952, and President Harry Truman signed it into law on April 15, 1952. At the moment it took effect, the United States maintained 260,000 troops in Japan, using 2,824 facilities across the country, with additional soldiers and bases in Okinawa, which remained under direct American control. A separate Administrative Agreement of 29 articles, spelling out the details of the basing arrangements, was negotiated in secret and made public on February 28, 1952, without a vote by either government's legislature.

Background

The treaty was imposed on Japan by the United States as a condition for ending the Occupation and restoring Japanese sovereignty. Japan had been under Allied occupation since its surrender in 1945, and the price of regaining control of its own affairs was a permanent American military presence on its territory.

The strategic logic was regional. The United States sought the territorial means to establish and sustain a military presence in the Far East, and Japan's geography made it the anchor of that posture. The treaty's prohibition on third-country bases ensured that no other power — in practice, the Soviet Union — could gain a military foothold in Japan.

For the Japanese government, the choice was between continued occupation and a sovereign state hosting foreign bases under terms it had not freely set. It signed.

Why It Mattered

The treaty created a military alliance between the United States and Japan that outlasted the treaty itself. It fixed the basic architecture of the relationship: American bases on Japanese soil, American control over how those forces were used, and a limit on Japan's ability to make independent military arrangements with other countries.

The absence of a mutual defence obligation was striking. The United States was not required to come to Japan's defence if Japan were attacked, and American forces in Japan could be deployed without consulting the Japanese government. For many Japanese, the treaty read less like an alliance than like an arrangement for hosting an occupying army under a new name.

The treaty had no set expiration date and no defined method of abrogation, which made it feel permanent and unaccountable. It provoked widespread protest across Japan. Out of that controversy came negotiations between Prime Minister Nobusuke Kishi and President Dwight D. Eisenhower, and on June 19, 1960, the treaty was superseded and replaced by the revised Treaty of Mutual Cooperation and Security between the United States and Japan. The original treaty formally ended on June 23, 1960.

The Name in Japanese

The Japanese name is 日本国とアメリカ合衆国との間の安全保障条約, read にほんこく（or にっぽんこく）とアメリカがっしゅうこくとのあいだのあんぜんほしょうじょうやく. In romaji: Nihon-koku to Amerika Gasshūkoku to no aida no anzen hoshō jōyaku. The everyday shorthand is 旧日米安保条約 (きゅうにちべいあんぽじょうやく, kyū Nichibei Anpo Jōyaku), "the old Japan–US Security Treaty," where 旧 (きゅう, kyū) means "former" or "old."

Breaking the full name down:

• 日 (に, ni) — sun; here short for Japan.
• 本 (ほん, hon) — origin, base; together 日本 (にほん, Nihon) means Japan.
• 国 (こく, koku) — country, state. 日本国 (にほんこく, Nihonkoku) is the formal name of the Japanese state.
• と (to) — the particle "and," joining Japan and the United States.
• ア (あ, a), メ (め, me), リ (り, ri), カ (か, ka) — katakana spelling out "America."
• 合 (がっ, ga') — to join, combine.
• 衆 (しゅう, shū) — multitude, masses.
• 国 (こく, koku) — country. 合衆国 (がっしゅうこく, gasshūkoku) means "united states," so アメリカ合衆国 is the United States of America.
• と (to) — "and," repeated.
• の (no) — possessive particle, "of."
• 間 (あいだ, aida) — interval, space between; との間の (とのあいだの, to no aida no) means "between."
• 安 (あん, an) — peace, safety.
• 全 (ぜん, zen) — whole, complete. 安全 (あんぜん, anzen) means "safety" or "security."
• 保 (ほ, ho) — to protect, preserve.
• 障 (しょう, shō) — obstacle, hindrance. 保障 (ほしょう, hoshō) means "guarantee" or "security."
• 条 (じょう, jō) — article, clause.
• 約 (やく, yaku) — promise, agreement. 条約 (じょうやく, jōyaku) means "treaty."

So the whole name reads, piece by piece, "Japan and United States between of security treaty." The compound 安全保障 (あんぜんほしょう, anzen hoshō) is the standard Japanese term for "security" in the military sense, and it recurs throughout postwar Japanese political vocabulary.

Key Figures

Nobusuke Kishi (岸信介, きしのぶすけ) — Prime Minister of Japan who negotiated with Dwight D. Eisenhower over the treaty's revision, leading to its replacement in 1960.

Dwight D. Eisenhower — President of the United States who negotiated with Kishi on the revised treaty.

Harry Truman — President of the United States who signed the original treaty into U.S. law on April 15, 1952, after Senate ratification on March 20, 1952.