For nearly six decades, Japan’s national identity has been anchored by a singular, painful distinction: as the only nation to have suffered a nuclear attack, it pledged never to possess, produce, or permit the entry of atomic weapons. But on a Sunday morning broadcast of the national broadcaster NHK, that long-standing taboo was publicly interrogated, signalling a profound shift in the security architecture of East Asia.
Itsunori Onodera, a former defence minister and a heavyweight in the ruling Liberal Democratic Party (LDP), told viewers that Japan must engage in “renewed discussions” regarding its Three Non-Nuclear Principles. While the government remains officially committed to these tenets, Onodera’s call to question their future utility reflects a growing anxiety within Tokyo over the reliability of the United States’ “nuclear umbrella” in an increasingly volatile region.
“Japan is under the US nuclear umbrella, which in its essence means a commitment by the United States to defend Japan, even if it requires the use of nuclear weapons,” Onodera said. “To ignore this nuclear discussion without any consideration is politically irresponsible.”
By the third paragraph of this unfolding diplomatic drama, the “nut graph” becomes clear: Japan is systematically peeling back layers of its post-war pacifism, driven by the dual pressures of a more assertive China and a nuclear-armed North Korea. Prime Minister Sanae Takaichi’s refusal to explicitly recommit to these principles suggests that Tokyo is moving toward a policy of “strategic ambiguity” that could redefine the power balance in the Pacific.
The Weight of Three Principles
The “Three Non-Nuclear Principles”—no possession, no production, and no introduction—were first articulated in 1967 by Prime Minister Eisaku Sato. They eventually became a national “creed,” earning Sato the Nobel Peace Prize in 1974. However, the modern LDP views these rules not as immutable laws, but as policy guidelines that may no longer fit the 2025 security landscape.
The three pillars are:
* Non-possession: Japan will not own nuclear weapons.
* Non-production: Japan will not manufacture nuclear weapons.
* Non-introduction: Japan will not allow nuclear weapons on its territory.
The friction point lies primarily with the third principle. Conservative lawmakers argue that forbidding the “introduction” of US nuclear assets into Japanese waters or ports weakens the very deterrence Japan relies upon. This is not a new debate—in 2011, a “2.5 principle” was proposed to formally allow US nuclear-armed vessels to visit Japanese ports—but under Takaichi, the conversation has moved from the fringes to the heart of government policy.
Takaichi’s “Realism” and the China Factor
Prime Minister Takaichi has been unapologetically blunt about her concerns. In her 2024 book Kokuryoku Kenkyu (National Power Research), she argued that sticking to the three principles could become an “obstacle” during a severe crisis. During parliamentary questioning last month, she pointedly refused to confirm if the principles would remain intact in the government’s upcoming security document review, scheduled for completion by the end of next year.
This ambiguity has infuriated Beijing. The Chinese Foreign Ministry on Monday expressed “grave concern,” linking the nuclear debate to Takaichi’s recent comments suggesting a Chinese attack on Taiwan would constitute a “situation threatening Japan’s survival.”
“The issue of nuclear weapons is not a political bargaining chip,” said Chinese Foreign Ministry spokesperson Guo Jiakun. He warned that Onodera’s remarks prove Takaichi’s stance on Taiwan was “no accident,” adding that China would not accept any “test of the limits of the international community’s patience.”
Regional Outcry and the “Red Line”
The backlash has not been confined to Beijing. In Pyongyang, the rhetoric was even more pointed. North Korea’s Ministry of Foreign Affairs described the move as a “challenge to the international community,” accusing Japan of harbouring “long-standing ambitions for nuclear armament.”
“Japan has revealed its ambition to seek nuclear weapons, crossing a red line for a state that committed war crimes,” a North Korean spokesperson stated via the official KCNA news agency. The statement warned that a nuclear-armed Japan would lead to a “major catastrophe” for humanity.
Within Japan, the public remains deeply conflicted. In a recent poll by Jiji Press, 46.6% of respondents argued that the “no introduction” principle should be maintained, significantly higher than the 28.2% who support an amendment.
The American Umbrella
While the US State Department publicly praised Japan as a “valuable partner in preventing nuclear proliferation,” the reality behind the scenes is more complex. Recent reports suggest that Tokyo and Washington have already discussed “extended deterrence” scenarios. These include how Japanese conventional forces—such as new long-range “counter-strike” missiles—might support US operations in the event of a US-China nuclear conflict.
The debate is now moving toward whether Japan should allow “temporary” entry of US nuclear assets, a move that would technically violate the third principle but, according to proponents like Onodera, would make the US deterrent “credible.”
As the LDP prepares to review its core security documents by 2026, the ghost of 1945 continues to haunt the deliberations. The government in Tokyo appears increasingly convinced that the “dignified foundation” of peace in East Asia can no longer be built solely on the absence of nuclear power, but on the careful, controversial management of it.
The kicker for Tokyo remains the same: in a region where its neighbours are rapidly expanding their arsenals, can the only nation to know the horror of the bomb afford to remain the only one without a seat at the nuclear table?
