Former Prime Minister Nobusuke Kishi set a two-year timeline to revise the postwar security treaty with the United States as a precursor to an amendment of the pacifist Constitution, according to diplomatic records declassified Wednesday.

Kishi, an archconservative and Prime Minister Shinzo Abe's grandfather, was preparing for his first visit to the United States as leader in 1957 when he started putting his plan into action.

Kishi's idea was to seek a revision to the security treaty which, at the time, was widely seen across the political spectrum as putting the country in a subservient position.