Japan, the only country to suffer a nuclear attack, has for decades sworn not to have atomic weapons on its soil. But following North Korea's July missile tests and its nuclear weapons test on October 9, some Japanese politicians are calling for a debate on whether Japan's nuclear policy. 

This is not the first time Japan has confronted the nuclear question.

In the 1960s, as China developed atomic weapons, then-Prime Minister Eisaku Sato proposed a Japanese nuclear bomb. The United States, and survivors of the American atomic bombings of Hiroshima and Nagasaki in 1945, objected.

Mr. Sato quickly reversed course, declaring his country would not make or obtain such weapons nor allow the United States or any other nation to bring them in. The prime minister pushed Japan to sign the nuclear Non-Proliferation Treaty, earning him the 1974 Nobel Peace Prize.

But the North Korean underground nuclear test on October 9 rocked Japan's establishment, and prompted a number of senior politicians here to call for a new debate on the issue.

Foreign Minister Taro Aso appears to be leading the call in these comments to a parliamentary committee.

He says now that North Korea has a nuclear weapon there is no reason for Japan not to debate whether it should also possess nuclear arms.

Other political heavyweights have expressed the same view in recent weeks, including Shoichi Nakagawa, the policy chief of the governing Liberal Democratic Party.

He says it is "only natural" such a discussion takes place in Tokyo now that his country is "surrounded" by nuclear weapons.

East-West Center policy analyst Sheila Smith in Hawaii, a specialist on Japanese security, says relying on the U.S. nuclear capability in the event of a regional war is being re-evaluated by Tokyo in light of North Korea's nuclear intentions.

"In the past we have always looked at a Japan that was willing to say 'Oh well, the U.S. will take care of that. We are not on the front line. We do not have a direct threat.' But now I think you have a Japan that does feel a direct threat and a generation of political leadership that's not hesitant to think of its job as primarily one of thinking of Japan's national security interest," she said.

U.S. officials are trying to reassure Japan that the American nuclear deterrent is enough. U.S. Ambassador Thomas Schieffer, speaking in Tokyo, drew on lessons from the Cold War to apply to Asia today. He says history shows that French President Charles de Gaulle did not need to go nuclear because it was not the French bomb, but the far larger U.S. nuclear arsenal that dissuaded the communist Soviet Union from attacking Europe.

"Charles de Gaulle made the same argument with regard to France that some would make in Japan today. Mainly that America cannot be counted on to risk its cities in defense of Paris or Tokyo," noted Schieffer. "All I can say is that history proved De Gaulle wrong."

A Japan with nuclear weapons would seriously alarm many of its neighbors, especially China and South Korea, which suffered from Japanese military aggression in the first half of the 20th Century.

Aware of Asian sensitivities, most Japanese politicians, from Prime Minister Shinzo Abe on down, are quick to say this is just a time to discuss all security options. They stress Japan has no plans to obtain nuclear weapons, despite possessing tons of plutonium, a sophisticated nuclear energy industry and civilian space launch capabilities.

Japan's Defense Agency chief, Fumio Kyuma, says he knows of no one in the government, including Foreign Minister Aso, who is actually proposing that Japan go nuclear.

He says despite what is being written in the newspapers, his position and that of the foreign minister are the same, namely, even if Japan were to debate the issue the conclusion would be that the country should maintain the status quo.

Senior researcher at the Japan Institute of International Affairs, Nobumasa Akiyama, says Japanese officials - even if they are considering the nuclear option - have to mind domestic politics.

"I do not think that the majority of the public would move in favor of the nuclear option. I think, especially, at this moment the politicians are quite sensitive to public opinion," said Akiyama. 

Sheila Smith, at the East-West Center, says she thinks the main reason Japan is raising the nuclear question is to send an assertive message that it may not stand idly by in the face of a North Korean nuclear threat.

"The audience that they are trying to figure out how to communicate with is Pyongyang, obviously, and China, but also it is going to be a domestic audience," added Smith.

Smith and other analysts suggest the talk is also intended to apply pressure on China to use its leverage to force its communist ally North Korea to abandon its nuclear programs.

Prime Minister Abe is adamant his government will adhere to the principles Japan adopted in 1972 to not possess, produce or allow nuclear weapons on Japanese soil.

But conservatives and liberals in Japan point out that this is not a binding doctrine, merely a parliamentary resolution, and there are no legal or constitutional barriers to prevent Japan abandoning its anti-nuclear principles in a changing global security environment.