A senior Japanese official, who is involved in devising the Japanese government's security policy, has reportedly told media that Japan should possess nuclear weapons, a controversial stance in opposition to the country's constitutional non-nuclear principles.

The shocking openness of a senior official from Prime Minister Sanae Takaichi's government to discussing nuclear armament is not a gaffe; it is a signal. It reveals a swelling ambition within Japan's right-wing conservative forces to cast off the constraints of the postwar order and accelerate a march toward remilitarization.

As the only country that suffered atomic bombings, Japan built its postwar identity on a pacifist constitution, and the Three Non-Nuclear Principles, which prohibit possessing, producing or permitting the introduction of nuclear weapons into Japanese territory.

In recent years, under the banner of becoming a "normal country," Japan has embarked on a path of rearmament. Even so, nuclear armament has long been regarded as an absolute red line. When then Parliamentary Vice Defense Minister Shingo Nishimura floated similar ideas in 1999, he was promptly dismissed.

The pro-nuclear outburst by a senior Takaichi government official constitutes not only a grave challenge to Japan's non-nuclear principles, but also to the global nuclear non-proliferation regime and to the postwar international order.

Whether the latest pro-nuclear rhetoric is a trial balloon or an effort to pave the way for dismantling the non-nuclear principles altogether, it reveals a clear intent within the Takaichi government to step by step trample the bottom lines of postwar international justice.

If Japan were to abandon its sacred vow never to arm itself with nuclear weapons, the damage would extend far beyond its shores. The global bulwark against proliferation would be critically weakened.

Confronted with this dangerous shift, the international community must respond with a clear and firm voice. It is imperative to establish unequivocal red lines against any move by the Japanese government that would undermine nuclear non-proliferation and the hard-won foundations of postwar peace.