Analysts forecast Japan would at least step up military ties with the United States, especially development of an anti-missile system begun after North Korea's launch of a long-range missile over the main Japanese island in

"It is possible for one country after another to follow North Korea's example in possessing nukes," Shigeru Ishiba, a former Japanese minister for defense, warned in a recent television talk show. "Japan will never do so."

But the idea of Japan acquiring the ultimate weapon, once taboo in the country which lost some 210,000 lives in the US atomic bombings of Hiroshima and Nagasaki, is now being openly debated amid a heightening nuclear threat from neighboring North Korea.

As a key US ally, Japan has begun to cast off its pacifist mantle by sending troops on a non-combat mission to Iraq, its first military deployment since World War II in a country at war.

Vice President Dick Cheney and other US conservatives have warned that the failure to end North Korea's nuclear ambitions could trigger an arms race in East Asia -- involving Japan, South Korea and Taiwan, all of them capable of producing nuclear weapons.

But a nuclear-armed Japan is widely seen at home as unrealistic while Tokyo maintains its 1967 policy against production, possession and presence of nuclear weapons in its territory protected by the US nuclear umbrella.

Cheney's warning "may have been used as a diplomatic card against China and belonged to the world of rhetoric," said Hideya Kurata, a professor of security affairs at Tokyo's Kyorin University.

In a May 19 report, the US Senate Republican Policy Committee said: "A test in North Korea would certainly raise the prospect of a major public debate in Japan over whether to turn its latent nuclear capabilities in its civilian and space sectors into an overt nuclear weapons program."

The policy paper called on Washington to demand Beijing, the main patron of Pyongyang, "make a choice: either help out or face the possibility of other nuclear neighbors."

Japan has an ample stockpile of plutonium derived by reprocessing spent fuel from the country's 52 nuclear reactors with a total capacity of 45 million kilowatts.

Japan has the technical capacity to produce nuclear bombs and mount them on missiles "within 90 days," said Kenichi Ohmae, a globally quoted Japanese consultant on management and socio-political issues.

In an interview with South Korea's Joong-Ang Ilbo newspaper in February, he estimated the stockpile at more than 50 tonnes, enough to make 2,000 plutonium bombs. Japan also has a space rocket which can double as an inter-continental ballistic missile.

Ohmae said that 90 percent of the Japanese are opposed to nuclear armament. "But I believe that public opinion will rapidly change if we are faced with the real threat of North Korean nuclear arms."

Hideshi Takesada, a professor at Japan's National Institute for Defense Studies, ruled out a nuclear chain reaction in East Asia.

"South Korea has come to consider North Korean nuclear weapons more as a bargaining chip and less as a military means," he said.

Japan has been seeking to "strengthen the credibility of the US nuclear umbrella and jointly develop a defense system," he said.

Takesada added that US President George W. Bush would never tolerate Taiwan's nuclear armament at a time when a cross-strait military clash with mainland China looms as a possibility.

Scott Snyder, a senior associate at the Asia Foundation, said Japanese or South Korean commitments to remain non-nuclear would probably depend "on the quality and satisfaction that exists with the US alliance system."

"While there may not be an immediate chain reaction, this does mean that we need to put the alliances and their durability under greater scrutiny," said the American expert on Korean affairs.

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