Farmers and supporters in Sunagawa (near Tokyo) protested plans to expand the U.S. Tachikawa Air Base, turning a local land dispute into a major national argument about U.S. bases and Japan’s postwar sovereignty. The confrontations helped build networks and tactics later used in the Anpo protest movement.
In the Sunagawa trespass case, the Tokyo District Court issued a ruling that (at that level) treated the U.S. security arrangement and bases as unconstitutional under Article 9’s limits on “war potential.” Even though it was later overturned, the decision raised the stakes for security-treaty politics as Japan moved toward a planned treaty revision.
Student activists forced their way into the National Diet compound, signaling a shift toward more confrontational “direct action” in the growing movement against the security-treaty revision. The action also widened tensions inside the broader opposition coalition over protest tactics and political strategy.
Japan’s Supreme Court reversed the district-court ruling, rejecting the idea that the security relationship and U.S. bases were unconstitutional. The decision undercut a key legal argument used by anti-base activists, but it did not end public controversy as treaty-revision plans advanced.
Prime Minister Nobusuke Kishi and U.S. leaders signed the revised Treaty of Mutual Cooperation and Security in Washington, D.C. The new treaty aimed to make the alliance more “mutual” than the 1951 version, but it also triggered fears that Japan could be drawn into U.S. wars and that U.S. bases would become more permanent.
With opposition lawmakers blocking proceedings, Kishi brought police into the Diet to remove Socialist members and pushed the treaty through the House of Representatives. Many Japanese viewed this as undemocratic, and it helped expand the protest movement from organized activists to much broader segments of the public.
A car carrying U.S. press secretary James Hagerty and Ambassador Douglas MacArthur II was surrounded by protesters near Haneda Airport, and the occupants were ultimately evacuated by helicopter. The widely circulated images intensified international attention and increased pressure on the Japanese government as the treaty fight escalated.
Mass demonstrations culminated in a violent confrontation at the National Diet compound, where student activists clashed with police. Tokyo University student Michiko Kanba died during the fighting, and her death became a powerful symbol that deepened public anger and uncertainty about the government’s handling of the crisis.
As political violence and anti-American demonstrations grew, President Dwight D. Eisenhower’s scheduled stop in Japan was canceled. The cancellation showed how the treaty controversy had become a diplomatic crisis as well as a domestic political conflict inside Japan.
After passing the lower house and surviving intense opposition, the treaty took effect when the ratification instruments were exchanged in Tokyo, replacing the 1951 security treaty. Although protesters could not stop the treaty, the struggle reshaped Japanese politics by showing the risks of forcing major security decisions without broad consent.
Kishi’s cabinet resigned following the nationwide turmoil around the treaty. The resignation marked a political turning point: even with the treaty in place, the episode signaled that future security-policy changes would face strong public scrutiny and could destabilize governments.
Japan Socialist Party leader Inejirō Asanuma was assassinated during a televised political debate by a right-wing युवक armed with a short sword. The killing underscored the high level of political tension in the aftermath of Anpo and added to fears about extremist violence in Japan’s democracy.
Large numbers of anti–Vietnam War protesters occupied and fought police around Shinjuku Station, targeting shipments connected to U.S. military operations. The riot showed how, later in the 1960s, opposition to the U.S.–Japan alliance shifted from the treaty text itself to how U.S. bases in Japan supported U.S. wars abroad.
Prime Minister Eisaku Satō and President Richard Nixon issued a joint statement indicating that Okinawa would be returned to Japan in 1972. The announcement mattered for Anpo-era controversies because Okinawa hosted major U.S. forces, and the terms of return became closely tied to debates about bases, nuclear issues, and the alliance’s future.
Under Article X, the 1960 security treaty could be ended after 10 years only if either party gave one year’s notice. Because no termination notice was given, the treaty continued, and the expected “1970 Anpo” confrontation became more about protests and political pressure than a formal legal renewal vote.
Anpo Protests and US–Japan Security Treaty Controversies (1958–1970)