Masashi Ishibashi, who chaired the now-defunct Japan Socialist Party during the 1980s, died in the city of Fukuoka earlier this month. He was 95.

After the end of World War II, Ishibashi, who was born in Taiwan, worked for the Allied Occupation forces in Sasebo, Nagasaki Prefecture.

After serving as secretary-general of the All Japan Garrison Forces Labor Union’s Sasebo branch and member of the Nagasaki Prefectural Assembly, Ishibashi was elected to the Lower House in 1955 as a representative from a constituency in Nagasaki. He was elected to the Lower House 12 consecutive times.

Ishibashi, known as being well-versed in the fields of diplomacy and defense, grilled Prime Minister Nobusuke Kishi over the revision of the Japan-U.S. security treaty in 1960 .

Ishibashi was part of the JSP’s “Anpo Gonin Otoko,” or the squad of five men with expertise in issues related to the security treaty. Also among them was former JSP Chairman Ichio Asukata.

In 1966, Ishibashi published his vision for the JSP to run on a platform of unarmed neutrality. He succeeded Asukata as party chairman in 1983 after serving as secretary-general and deputy chairman.

As chief, Ishibashi argued, among other things, that the Self-Defense Forces are unconstitutional but legal. He also put together a new party declaration that highlighted the JSP’s determination to transform into a party capable of taking power.

Ishibashi resigned as chairman to take responsibility for the party’s setback in simultaneous elections for both chambers of the Diet in 1986. He was succeeded by the iconic late party leader Takako Doi.

He retired from politics in 1990.