TOKYO - The Japanese government is considering explicitly stating an exception to its long-standing non-nuclear principles in an updated security strategy, a source familiar with the matter said Thursday, apparently aiming to enhance the effectiveness of U.S. nuclear deterrence protecting Japan.
One option under consideration is to state in the document that Japan would allow nuclear weapons to be brought into the country in an emergency, reflecting a position outlined by a foreign minister in parliament in 2010 and endorsed by successive governments, including that of Prime Minister Sanae Takaichi.
The three principles, upheld by Japan as the only country to have suffered nuclear attacks, prohibit the possession, production or introduction of nuclear weapons.
Before becoming prime minister, Takaichi, known as a security hawk, expressed doubts about the principle of not allowing nuclear weapons into Japan, which could complicate port calls by nuclear-armed U.S. vessels and weaken the credibility of U.S. nuclear deterrence in a contingency.
While likely stopping short of revising the three principles themselves, the government is leaning toward explicitly stating an exception to them in the National Security Strategy, which is to be updated along with other related documents by the end of the year.
Stating the exception in an official government document would likely signal a stronger commitment than remarks made in parliament. In that case, the government would also have to establish criteria for allowing nuclear weapons into Japan and procedures for decision-making by both the Japanese and U.S. governments.
The move could also fuel Chinese accusations of Japanese "neo-militarism" amid Takaichi's push to bolster the country's defense capabilities.
The exception to the three non-nuclear principles was raised in March 2010 by then Foreign Minister Katsuya Okada during a parliamentary committee session when the now-defunct Democratic Party of Japan was in power.
"If Japan's safety cannot be guaranteed without allowing a temporary port call by a U.S. vessel carrying nuclear weapons, the government should stake its fate and make a decision, and explain it to the public," he said.
The three non-nuclear principles came under intense scrutiny more than a decade ago when a Japanese Foreign Ministry panel acknowledged the existence of a secret Cold War-era pact under which Tokyo allowed nuclear-armed U.S. vessels to visit Japanese ports without the required prior consultation. Okada led the investigation that uncovered the pact.
After taking office in October last year, Takaichi initially said she shared Okada's view on the exception. But she appeared to shift her position last month, telling a parliamentary committee that there was "room for consideration" regarding how the upcoming security documents should address U.S. extended deterrence and Okada's remarks.
Extended deterrence refers to the U.S. commitment to use its full range of nuclear and conventional capabilities to defend Japan, which faces an increasingly challenging security environment amid China's growing military assertiveness and North Korea's nuclear and missile threats.
Meanwhile, Foreign Minister Toshimitsu Motegi said in October that the government needed to consider how other countries might perceive the move if Japan explicitly included Okada's remarks in the security documents.
The actual wording may become a key issue in working-level consultations between the Liberal Democratic Party, some of whose members are wary of revising the three principles, and its junior coalition partner, the Japan Innovation Party, which is more supportive of a change.
Leaving the three principles unchanged while referring to Okada's remarks as an exception in the security documents could provide a compromise, the source said.
In the current National Security Strategy, adopted in 2022, the government pledged to maintain an exclusively defense-oriented policy, refrain from becoming a military power that poses a threat to other countries and uphold the three non-nuclear principles.
