Japan rejected a U.S. proposal to include Tokyo's desire to quickly ratify the Nuclear Nonproliferation Treaty in a joint statement issued in 1973 by Prime Minister Kakuei Tanaka and President Richard Nixon.
Diplomatic documents that have just been declassified show that the Japanese government resisted the U.S. proposal by citing opposition from some lawmakers in the ruling Liberal Democratic Party.
The proposed clause did not appear in the statement that was issued in Washington on Aug. 1, 1973.
Japan signed the Nuclear Nonproliferation Treaty in February 1970 but had yet to ratify it. At the time, the government went on record as saying the nuclear powers needed to make disarmament efforts before it would ratify the pact.
However, the documents indicate that the government in reality wanted to avoid upsetting hawkish elements in the LDP who advocated arming Japan with nuclear weapons.
One of the declassified documents, dated Aug. 13, 1973, says the United States proposed during working-level negotiations that the joint statement incorporate a clause saying the prime minister had told the president that Japan would contribute to disarmament by ratifying the NPT.
Japanese officials told U.S. negotiators that LDP lawmakers were divided over the matter and inserting such a clause in the joint statement would create the impression that Japan had succumbed to U.S. pressure, according to the document.
This would have an adverse effect on the government's efforts to ratify the pact at an early date, the document, which was compiled after the Tanaka-Nixon summit, says.
The U.S. government finally accepted Japan's contention and the clause was dropped, it says.
Behind Washington's proposal were persistent concerns among Americans about Japan's possible nuclear armament, diplomatic experts say.
Japan ratified the pact in June 1976.