Fearful Japanese may add nuclear arms in a decade
North Korean missile tests could provoke a policy change
Mounting fury at North Korea's missile launches could see Tokyo turn its back on its non-nuclear principles, military analysts say, with one expert estimating it could happen in as little as a decade.
And while arming the country with nuclear weapons has been hinted at in the past, no prime minister felt he had public support for the move.
But fearful that Japan could be the target of a North Korean attack - a concern heightened by statements from Pyongyang threatening retaliation if Tokyo does not rescind sanctions imposed since the missile tests - ordinary people are expressing support for more military muscle.
'The Japanese people are very angry and very worried and, right now, they will accept any government plan for the military,' said Tetsuo Maeda, a professor of defence studies at Tokyo International University.
'In the short term, there will be more Patriots and Aegis destroyers in the Sea of Japan, but I think that will change as soon as Shinzo Abe becomes prime minister,' he said referring to the sea known to Koreans as the East Sea.
As the chief cabinet secretary, the hawkish Mr Abe is favoured to take over from Prime Minister Junichiro Koizumi when he steps down in September.
'He will be far more hardline on Pyongyang and I'm firmly of the opinion that he intends to make Japan a nuclear power,' Professor Maeda said.
Since the end of the second world war, Japan has had a policy of not owning, developing or allowing nuclear weapons to transit its territory, although Mr Abe has stated his opposition to sticking to the position. It is also one that few people believe is actually enforced.
'The budget would be easy to secure, the nuclear technology is relatively simple and we have rocket know-how, so the delivery system is available,' Professor Maeda said.
He said he thought it could take a decade for public opinion to allow nuclear weapons, but that could change if North Korea 'continues like this' or if South Korea said it had them.
Nuclear weapons have been almost a taboo subject in Japan since the bombings of Hiroshima and Nagasaki, although Japan has more than 30 nuclear power plants and significant amounts of plutonium.
Many Japanese feel hemmed in by the nuclear powers of China, Russia and now North Korea, and are concerned that the US' priority is with its own security.
While Pyongyang's missile tests have provoked thought of Japan's right to a first-strike capability and the nuclear option, government officials do not appear to be discussing it yet.
'Of course Japanese people feel less safe than they did in the past but I'm not sure that we are yet at the point when Japanese government circles might start discussing a nuclear option,' said an analyst at the National Institute for Defence Studies. Others say they are pleased that Pyongyang revealed its hand.
'Personally, I was very happy to hear that the North Koreans had launched their missiles,' said Yoichi Shimada, a professor of international relations at Fukui Prefectural University. 'Their government forges currency, they abduct Japanese people, they import drugs into Japan and now they are firing missiles.
'Japan should have cruise missiles that we can use to attack the launch sites before North Korea can fire them.'
Professor Shimada also said 'the vast majority' of people thought Japan should be able to carry out a first-strike attack.
A spokeswoman for the Defence Agency in Tokyo said there had been no debate within the agency or government of going nuclear.
The White House this week warned that the region faces an arms race, possibly involving atomic weapons.