Diplomatic Documents Released: Japan’s lacked readiness for contingency

Editorial

15:04 JST, December 25, 2025

The Japanese government showed an insufficient sense of urgency regarding North Korea’s nuclear development, and the United States had a growing distrust toward Japan. It is vital to learn from the lessons of the Japanese government’s delayed response at that time.

Japanese diplomatic documents from 1994 have been released. Among them, documents concerning the Japan-U.S. summit held in February during then Prime Minister Morihiro Hosokawa’s visit to the United States detail discussions on the North Korean nuclear issue.

Then U.S. Secretary of State Warren Christopher, who attended the summit, mentioned the possibility of a contingency on the Korean Peninsula, telling Hosokawa that there was a need to think about it. He also requested Japan’s cooperation should the U.N. Security Council impose sanctions on North Korea.

At the time, North Korea reacted strongly, stating that sanctions would be regarded as a declaration of war. The United States pressed Japan to undertake minesweeping operations if the United States were to impose a maritime blockade and if North Korea laid mines in response to it, according to the documents.

During the talks, Hosokawa responded that Japan would take responsible action within the scope permitted by domestic law.

Reflecting on that time, Hosokawa recently revealed that his government had considered its response. However, he said the government came to the conclusion that cooperating with the U.S. military could potentially lead to exercising the right to collective self-defense, making it impossible to comply with the U.S. request.

The year before this summit, North Korea had declared its withdrawal from the Nuclear Nonproliferation Treaty.

Meanwhile, Japan at the time was politically unstable with frequent changes of prime ministers, apparently making it difficult to focus on security policy. But it is undeniable that Japan had a low level of crisis awareness.

Other released documents also showed that the then U.S. Senate majority leader pressed Hosokawa, asking why the United States should worry about the North Korean situation when Japan, as a nation neighboring it, was not deeply concerned.

Ultimately, this nuclear crisis was averted through U.S. diplomatic efforts. Had a contingency occurred, however, the relationship of mutual trust between Japan and the United States could have been undermined.

In 2015, Japan enacted security-related laws that allow the nation to exercise the right to collective self-defense in a limited manner. It is significant that security legislation was established in line with reality.

However, it cannot be said that a sense of urgency regarding a contingency has been widely developed.

Katsuya Okada of the main opposition Constitutional Democratic Party of Japan pressed Prime Minister Sanae Takaichi for a response at the Diet, on his presumption that even if a Taiwan contingency occurred and a maritime blockade were imposed, ships could simply bypass the blockade area, meaning it would not constitute a survival-threatening situation for Japan. The ensuing debate has triggered China’s criticism of Japan.

At the level of Diet debate, the gap between reality and security perceptions continues.

(From The Yomiuri Shimbun, Dec. 25, 2025)