In South Korea and Japan there is increasing support for the deployment of nuclear weapons to defend against the growing North Korean threat, and due to public concern that the U.S. may no longer be counted on to aid allies with extended nuclear deterrence.
The U.S. Defense Intelligence Agency estimates North Korea may have as many as 60 nuclear weapons, and that it might have successfully miniaturized nuclear warheads to fit on its arsenal of 1,000 missiles.
But what is changing the security calculus for both the U.S. and Asia is North Korea’s rapid progress toward developing a long-range intercontinental ballistic missile (ICBM) that could target the U.S. mainland.
This development is raising concerns that Washington may not risk nuclear war with North Korea to fulfill longstanding mutual security obligations to defend its allies.
“People have some doubt that Washington will really protect Seoul or Tokyo at the expense of Washington or Seattle or New York,” said Park In-kook with the Korea Foundation for Advanced Studies and a former South Korean deputy foreign minister. Park moderated an expert panel on the North Korean nuclear threat at the World Knowledge Forum in Seoul on Tuesday.
During the U.S. presidential campaign, then candidate Donald Trump also sowed doubts about America’s commitment to allies in the region, when he said he would consider withdrawing troops from the region and allowing Asian Pacific allies to acquire their own nuclear weapons if they did not significantly increase defense payments to the United States. Since taking office, however, the Trump administration has offered multiple reassurances of the U.S. commitment to its allies.
In a September public opinion survey, over 60 percent of South Koreans were in favor of their country acquiring its own nuclear deterrent, whether that be through the deployment of U.S. tactical nuclear weapons or by developing their own.
In Japan, the only country to suffer a nuclear attack, only 9 percent supported acquiring nuclear weapons according to a poll in July. But North Korea’s recent tests of two intermediate-range ballistic missiles (IRBMs), which flew directly over northern Japanese territory, have increased public support for conservative Prime Minister Shinzo Abe’s efforts to bolster the nation’s defenses.
And in September, former Japanese defense minister Shigeru Ishiba publicly questioned whether the U.S. can still be trusted to protect Japan.
Japan has a civilian nuclear power industry and is believed to have sufficient fissile materials and technology needed to quickly develop nuclear weapons, if the country decided to do so.
But there are multiple arguments against the deployment of nuclear weapons by Seoul and Tokyo, as experts believe that such a move would likely legitimize North Korea’s nuclear program, and greatly weaken the international community’s commitment to maintain pressure on North Korea to denuclearize through economic sanctions.
China would shift from cooperating to restrain North Korea to focusing on the emerging nuclear security threat, especially from Japan with its history of military aggression in Asia.
“Japan in trying to take or, in other words, [exploit] some sort of a DPRK (Democratic People's Republic of Korea) factor to re-militarize, well that would scare the Chinese bad,” said Shu Feng, the director of the Institute of International Studies in Nanjing University in China.
Japan and South Korea would also be in violation of the Non Proliferation Treaty (NPT) they signed as non-nuclear weapons states and could be subjected to international sanctions as well.
The United Nations might also impose economic and diplomatic sanctions on South Korea for developing nuclear weapons.
From a military standpoint, deploying U.S. tactical nuclear weapons in South Korea in particular does not make sense. The tactical weapons the U.S. withdrew from the Korean Peninsula in the 1990s are considered obsolete. Analysts say the U.S. now keeps its nuclear weapons in undisclosed submarines and aircraft.
Deploying them in stationary locations in South Korea would lose the element of surprise and make them more vulnerable to a North Korean strike.
“You have increased the likelihood that North Korea will engage in a preemptive attack on that very high value target, and in a crisis you may even feel constrained from removing the nuclear weapons from the bunker, lest it cause North Korea to think you are about to attack them,” said Bruce Klingner, a former CIA analyst who is now senior research fellow at the conservative Heritage Foundation.
The U.S. and its allies in Tokyo and Seoul have so far moved to counter North Korea’s nuclear capabilities by building up missile defenses and conventional weapons.
Japan has requested to purchase a $113 million an AIM 120C-7 Advanced Medium Range Air-to-Air Missiles (AMRAAMs) system from the U.S.
The U.S. military has also deployed the Terminal High Altitude Area Defense (THAAD) missile shield in South Korea.
Youmi Kim in Seoul contributed to this report.