Prime Minister Kiichi Miyazawa in 1993 told U.S. officials he was concerned about the “direct threat” posed by North Korea’s nuclear weapons development, one month after Pyongyang withdrew from the Nuclear Nonproliferation Treaty.

The exchange between Miyazawa and U.S. President Bill Clinton and other officials was revealed in diplomatic documents released by the Foreign Ministry on Dec. 26.

Miyazawa appears to be about the only Japanese official who took seriously North Korea’s decision in March 1993 to withdraw from the NPT. Suspicions had been swirling that Pyongyang was developing nuclear weapons even while a part of the treaty.

Other documents pertaining to preparations made by Foreign Ministry officials before Miyazawa’s visit to Washington in April 1993 show little concern among Japanese diplomats about North Korea’s nuclear weapons development program.

On the afternoon of April 16, 1993, Miyazawa met with Clinton at the White House and told him that the only way to dissuade North Korea would be to get China to urge Pyongyang to abandon its nuclear weapons development.

After his meeting with Clinton, Miyazawa returned to his hotel where he was visited by U.S. Defense Secretary Les Aspin and Gen. Colin Powell, the chairman of the Joint Chiefs of Staff.

The document containing the exchange between Miyazawa and the top U.S. military officials was marked “top secret.”

While Miyazawa said the U.S. military presence in Japan was indispensable even with the end of the Cold War, he added that since Japan had abandoned possession of nuclear weapons, any development by North Korea of nuclear weapons and methods to transport such weapons would be a “direct threat” to Japan.

When Aspin said that diplomatic efforts would continue, Miyazawa asked, “Since the United States has withdrawn its nuclear weapons from South Korea, would there not be a fundamental change in regional balance if North Korea succeeded in developing nuclear weapons?”

The nuclear weapons were removed from South Korea after the 1991 agreement by the two Koreas to denuclearize the Korean Peninsula.

In response to Miyazawa’s concerns about the continued strength of the U.S. nuclear umbrella, Powell said it would be important to pass on a message to North Korea that developing nuclear weapons was foolhardy because the U.S. nuclear deterrent was still very effective.

Miyazawa then asked Powell about whether North Korea had developed small nuclear warheads that could be transported on ballistic missiles.

Powell said his personal opinion was that it would take a number of years before North Korea could develop nuclear warheads, but that efforts had to be made to stop North Korea from the nuclear weapons development program that had come to light.

Although later negotiations between the United States and North Korea led to an agreement by Pyongyang to remain in the NPT, it continued to develop nuclear weapons. That fact came to light in 2002, and four years later, Pyongyang conducted its first nuclear test.

Economic sanctions imposed by various nations did not stop North Korea’s development efforts.

The document regarding the Miyazawa-Clinton meeting at the White House also records an exchange between Anthony Lake, the national security adviser, and Miyazawa.

When Lake asked if it was possible to construct a long-term relationship with a nation like North Korea that pursued nuclear weapons development even while part of the NPT, Miyazawa noted that it was extremely difficult to stop such development through economic sanctions. He pointed out Japan’s efforts during World War II even after economic sanctions were imposed on the nation.

An expert on North Korea’s nuclear weapons development said Miyazawa’s concerns were likely not passed on to the next administration.

Miyazawa’s ruling Liberal Democratic Party lost control of the government after the July 1993 Lower House election, and Morihiro Hosokawa took over as prime minister in a coalition government.

Narushige Michishita, a professor of strategic studies at the National Graduate Institute for Policy Studies, said the failure of passing on Miyazawa’s concerns to the succeeding administration was one factor behind the Japanese government’s inept handling of the North Korean nuclear weapons crisis the following year.

(This article was written by Shun Suzuki and Naotaka Fujita, a senior staff writer.)