Nuclear-Arming Japan, South Korea: Is It Feasible and Desirable?
The Korea Times Column

Nuclear-Arming Japan, South Korea: Is It Feasible and Desirable?

In short it is feasible but not desirable for South Korea and Japan to become nuclear-armed.

First, think about the catastrophic devastation of the use of nuclear weapons. A simulation of a today’s typical strategic nuclear bomb detonated in central Mumbai showed 1.1 million deaths and 2.2 million casualties.

In the U.S., Russia and all others combined, there are 17,000 of such bombs in the world today. Humankind would be brought close to annihilation if a nuclear war starts. It is almost insane to think about using nuclear bombs. Pope Francis called them “immoral” in Japan recently.

Still, countries hang on to nuclear bombs and North Koreans are building them. Should South Korea and Japan join them? No, both countries should think about ways to secure their national security without joining the ranks of “immorals.”

Practically, as far as their alliances with the U.S. are firm and its extended nuclear deterrence covers them, South Korea and Japan don’t need nuclear weapons to defend themselves.

The credibility of the American extended nuclear deterrence has been shaken recently due to the erratic utterance by President Donald Trump that Japan and South Korea might as well acquire nuclear weapons to defend themselves against the North Korean nuclear threat rather than continue depending on the U.S.

This certainly caused a concern in both countries about the dependability of the American nuclear deterrence, but the prevailing view among American security experts and policymakers is that the alliances with the U.S. are not solely for the benefit of the allies but also for the overall benefit of the U.S.

Without the alliances, the U.S. would be pushed back to the middle of the Pacific Ocean and have to defend itself from there. The maintenance of close economic, industrial and technological alliances with the advanced economies of South Korea and Japan would be an essential element for the future well-being of the U.S., Japan and South Korea.

Thus, the U.S. alliance and its extended nuclear deterrence should better be maintained as long as South Korea and Japan face nuclear threats. If North Korea accepts its denuclearization realizing a nuclear-free Korean Peninsula, the need for the nuclear extended deterrence will be greatly reduced.

Another way to reduce the practical possibility of the use of nuclear weapons is to strengthen the application of the principles of international humanitarian law that prohibit indiscriminate, unnecessary and disproportionate use of force even during warfare.

If these principles are strictly applied, there will be very limited cases where the use of nuclear bombs are permitted. Let us proclaim that anybody who broke the rule will be brought to justice.

With the advanced industrial and technological bases of South Korea and Japan, it would not be difficult for them to produce nuclear weapons and missiles to deliver them. So, it is not a matter of feasibility but a political choice.

To acquire nuclear weapons South Korea and Japan would have to withdraw from the Nuclear Non-Proliferation Treaty (NPT), cancel safeguards agreements with the International Atomic Energy Agency (IAEA) and leave bilateral nuclear cooperation agreements with the U.S.

This would sever the civil nuclear cooperation with the U.S. and other members of the export control regime called the Nuclear Suppliers Group and put the civil nuclear industries in both countries in hardship. Uranium and nuclear fuel supply may be disrupted and technical cooperation may be cut off. License agreements may be canceled.

A persistent misunderstanding is in the argument that Japan or South Korea needs to maintain their nuclear industries, in particular, the spent-fuel reprocessing plant in Japan.

But you do not need a huge reprocessing plant that can produce a maximum 8 tons of plutonium a year. North Korea is continually building plutonium bombs using a laboratory-sized facility.

Such argument agitates unnecessary speculation about Japanese intentions. The nuclear industry and reprocessing plants should be maintained or abandoned on their own merits, not for any hidden intentions.

The important thing is for South Korea and Japan to maintain their strong political, economic and industrial ties with the U.S. that back up the close security ties with America. If you have to keep an alliance with a nuclear power in the real world, the U.S. is definitely the best ally you can find in today’s world.


Nobuyasu Abe (, former U.N. under-secretary-general for disarmament affairs, spent last year at Harvard Belfer Center for Science and International Affairs. The Korea Times published his article in cooperation with the Asia-Pacific Leadership Network for Nuclear Non-Proliferation and Disarmament (APLN).

This article was first published in The Korea Times on 25 December 2019 and is part of dedicated, regular column with analysis by APLN members on global issues. You can access the original post here

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