U.S. Republican presidential front-runner Donald Trump, known for proposing unconventional solutions to problems, has come up with an idea that he said would significantly reduce U.S. security burdens in Asia: arming South Korea and Japan with nuclear weapons.

Trump's remarks have added weight to calls in South Korea for the country's own nuclear armament in the wake of North Korea's fourth nuclear test in January and a long-range missile test in February. Talking seriously about the topic itself is a sea change given that the idea has long been flatly discounted as nonsense.

Trump first broached the idea in an interview published Friday, arguing that the U.S. is no longer rich enough to defend other countries and the possibility of allowing the allies to go nuclear is something that "we have to talk about."

He repeated the point again during a town hall meeting televised on CNN Tuesday night.

"Can I be honest are you? Maybe it's going to have to be time to change, because so many people, you have Pakistan has it, you have China has it. You have so many other countries are now having it," Trump said, referring to the U.S. nonproliferation policy.

"At some point we have to say, you know what, we're better off if Japan protects itself against this maniac in North Korea. We're better off, frankly, if South Korea is going to start to protect itself," Trump said, referring to North Korean leader Kim Jong-un.

The White House rejected Trump's idea as destabilizing, stressing that it could give Pyongyang justification for its nuclear development and reassuring U.S. commitment to defend the ally.

"Mr. Trump's suggestion that somehow we should encourage our allies in South Korea to develop nuclear weapons is directly contrary to a policy that the United States has long pursued and is directly contrary to a policy that the international community has long supported," White House press secretary Josh Earnest said.

"And it's hard for me to imagine why it would be a good idea to give the North Koreans any justification or any incentive to further accelerate their nuclear weapons program. It doesn't make any sense," he said. "What protects South Korea and Japan is knowing that they have the steadfast support of the most powerful country in the world."

The North's nuclear and missile tests have led some leading members of South Korea's ruling party to make the case for nuclear armament, arguing that it makes no sense to rely on the U.S. "nuclear umbrella" as the North's nuclear arsenal grows. 

"A lesson from the Cold War is this irony that peace can be maintained when nuclear weapons are responded with nuclear weapons," former party leader Chung Mong-joon said in an article posted on his blog. "Negotiations aimed at ending nuclear weapons can be possible only when we have powerful means corresponding to nukes."

Cheong Seong-chang, senior research fellow at the state-run South Korean think tank Sejong Institute, has also openly called for nuclear armament, saying it will bring a number of benefits to the country, including maintaining military balance between the two Koreas.

"The time has come for Seoul to consider nuclear armament from the standpoint of self-defense rather than relying only on the U.S. nuclear umbrella or U.N. Security Council sanctions," Cheong said in an article contributed to a local magazine.

But the government dismissed the idea, saying it runs counter to the principle of a nuclear-free Korean Peninsula.

American security experts have also called either for allowing Seoul to seek its own nuclear deterrent or for greater efforts to reassure the Asian ally so as to dissuade it from such a temptation. 

Doug Bandow, a Korea expert and senior fellow at the Cato Institute, said in an article earlier this month that U.S. policymakers "should consider the possibility of a nuclear South Korea," arguing that protecting the South is "not worth creating an unnecessary existential threat to the American homeland."

Many experts say that it won't be difficult for South Korea to develop nuclear weapons as the country has a robust nuclear industry in which nuclear reactors produce large quantities of spent fuel that could be reprocessed into weapons-grade plutonium.

Mark Fitzpatrick, a nonproliferation expert who heads the U.S. office of the London-based International Institute for Strategic Studies, said in a recent book that if a new nuclear-armed state were to emerge in Northeast Asia, it would most likely be South Korea. 

Most American experts, however, don't buy the case for Seoul's nuclear armament.

"South Korean proposals for the return of U.S. tactical nuclear weapons to the peninsula or the development of an indigenous nuclear program are the result of declining trust in U.S. resolve.

Neither proposal is practical," Bruce Klingner, a senior Korea expert at the Heritage Foundation, told Yonhap News Agency.

The U.S. ground-based nuclear weapons removed in the 1990s no longer exist and placing U.S. sea- and air-based nuclear weapons into storage bunkers in South Koea would be counter-productive and provide Pyongyang with a high-value target to strike preemptively, he said.

"A South Korean nuclear program would divert large portions of the South Korean defense budget from critical requirements to duplicate an existing U.S. capability. A better policy proposal would be to study how best to affirm the value and strength of the US nuclear deterrent to reassure our allies," he said.

Richard Bush, a senior researcher at the Brookings Institution, said it's premature to take Trump's idea seriously.

"Trump is not yet the nominee, and even if he is the nominee he won't necessarily be president," he told Yonhap. 

"Even if he becomes president, he may gain a more favorable view of South Korea's contribution to American security, of the US's extended nuclear deterrence pledge to the ROK, and of the importance of sustaining the credibility of that pledge in the hearts and minds of Koreans," he added.

Evans Revere, a former U.S. diplomat and senior adviser for the Albright Stonebridge Group, also strongly criticized the idea, saying it reflects a "profound lack of understanding of the importance of the international non-proliferation regime. 

"Trump's encouragement of a nuclear-armed Japan and South Korea would exacerbate an already complicated security situation in Northeast Asia and turn the region into a potential powder keg," Revere said. 

"It would justify an even larger and faster nuclear buildup by North Korea. It would compel China to greatly expand its own nuclear arsenal, greatly increasing the threat to the ROK and Japan, as well as to the United States," he added. (Yonhap)