Another war on the Korean Peninsula — this time a nuclear one — is beginning to look more possible than ever before, stirring anxiety in Japan and prompting debate over how it should respond.

Amid the crisis, Prime Minister Shinzo Abe has maintained close contact with U.S. President Donald Trump, holding teleconferences at an unprecedented rate and fully supporting his threat to use the military option if necessary.

Abe’s full support for Trump has caused concern among Japanese liberals dedicated to the war-renouncing Constitution. But at the same time, few alternatives to backing its security ally the United States have actually been proposed.

The Japan Times recently interviewed three noted Japan-based security experts to get their views on how Tokyo should respond.

While their views and proposals all differ, all emphasized that the crisis should be seen in a broader context, though much of the public’s attention has been drawn to the military threat directly posed by North Korea.

Tsuneo Watanabe, a senior research fellow at the Sasagawa Peace Foundation in Tokyo, pointed out that the North’s recent development of an ICBM has not really increased the direct threat to Japan: Pyongyang has for years deployed dozens of intermediate-range ballistic missiles that can directly hit Japan and may even have mountable nuclear warheads as well.

What is altogether the more alarming aspect of the crisis is that a failure to stop Pyongyang will encourage many other nations and terrorist groups to pursue the same strategy — developing nuclear arms while defying international pressure, Watanabe said.

Allowing North Korea to be a nuclear power “would lower the hurdles for other countries to own nuclear weapons. Many nations would try to acquire nuclear weapons, and some would succeed,” Watanabe said.

“It would mean the collapse of the NPT system,” Watanabe said, referring to the Treaty on the Non-Proliferation of Nuclear Weapons.

The public appears to be mainly worried that North Korea’s nuclear and missile capabilities could weaken the U.S. nuclear umbrella protecting Japan.

But the collapse of the NPT system and the spread of atomic weapons to rogue nations and terrorist groups is considered a more scary scenario for Japan and the rest of the world, Watanabe said.

“What Japan should do now is to try to have China, Russia, Europe and Southeast Asian countries understand that” and jointly stop Pyongyang’s nuclear and missile programs, Watanabe said.

In that sense, it would be “suicidal” for Japan to develop and possess nuclear weapons of its own because it would only hasten the demise of the NPT, he said.

Watanabe also pointed out that anti-nuclear sentiment obviously remains strong in Japan in light of the 1945 atomic bombings of Hiroshima and Nagasaki.

According to a Japanese-South Korean poll joint conducted in June and July by the Tokyo-based Public Opinion Research Center and the Seoul-based Hankook Research Co., 74.7 percent of 1,000 Japanese respondents said they oppose the idea of Japan possessing nuclear weapons.

In South Korea, however, 67.2 percent of Korean respondents support going nuclear.

Watanabe said openly keeping U.S. nuclear weapons in Japan and sharing control with Washington may be one way for Tokyo to strengthen its nuclear deterrence against Pyongyang.

But it would be extremely difficult for the government to make that decision, given the strong public aversion to atomic weapons, Watanabe said.

Narushige Michishita, professor of international relations at the National Graduate Institute for Policy Studies in Tokyo, has been observing the North Korean crisis in a level-headed manner despite the heated public debates over the dangers facing Japan.

Michishita argues that Pyongyang has no reason to directly attack Japan unless war breaks out on the Korean Peninsula and Japan attempts to support U.S. forces during a second Korean War.

“I myself don’t believe the risks for Japan have increased as is perceived among the public in general,” he said. “The North Koreans won’t regard Japan as an enemy as long as Japan does not help defend South Korea. Rather, they want to normalize their relationship with Japan,” he said.

Michishita agrees with other experts that the situation has become significantly more dangerous for Japan.

Pyongyang’s “lofted” midrange missiles would be even more difficult to intercept at such high speeds, and a hydrogen bomb would be far more destructive than anything seen at Hiroshima and Nagasaki, Michishita said.

Having said that, Michishita doesn’t believe nuclear war on the Korean Peninsula is likely for now. Instead, North Korea is more likely to keep showcasing its military superiority over archenemy South Korea and even engage in a military clash or two while simultaneously threatening the U.S. and Japan against interfering with its arms programs, Michishita said.

“It is South Korea that is facing the greatest risk now,” he said.

Both Watanabe and Michishita maintain that Abe is taking the right approach by building a close relationship with Trump and fully endorsing his administration’s policies.

“What Abe has achieved is a great success. Now Trump trusts him very much, so it is unlikely the U.S. will take any unilateral action without consulting Abe,” Michishita said.

“That is really good for Japan.”

In the meantime, Kyoji Yanagisawa, a former assistant chief Cabinet secretary, offered a different opinion.

The former Defense Ministry official was one of the most outspoken opponents of Abe’s successful effort to reinterpret, rather than amend, the Constitution and enact security laws in 2015 that gave the Self-Defense Forces greater legal leeway to support the U.S. military.

Under Article 9 of the Constitution, Japan’s use of force is strictly limited to self-defense. But under Abe’s reinterpretation and the new security laws, Abe claims the right to collective self-defense can be used to support the U.S. if Japan’s “survival” is deemed at stake.

The U.N. right allows Japan to attack a third country that is attacking an ally — presumably the U.S. in Japan’s case — even if Japan itself is not under attack.

“Without the security laws, Japan would be able to draw a line to distance itself from any war involving America. But now it can’t, which has increased the danger” to Japan, Yanagisawa said.

At the same time, Yanagisawa believes Japan has already exhausted its diplomatic options in dealing with the North Korea crisis.

It is only the U.S. that can negotiate with North Korea because Pyongyang is developing nuclear weapons out of fear that the regime of leader Kim Jong Un could eventually be ousted by Washington, Yanagisawa said.

“Whether the nuclear weapons program can be stopped or not all hinges on the U.S.-North Korea relationship,” Yanagisawa said.

“Japan is not a player. There is nothing Japan can do now,” he argued.

Watanabe of the Sasagawa Peace Foundation, however, would disagree.

He argued it is Abe who has actively involved the U.S. in the North Korean crisis.

“After Trump took power, the U.S. has followed initiatives pushed by Japan,” Watanabe said, adding that this differs significantly from the practices of past Japan-U.S. relationships.

This is partly because Trump is still unable to find enough senior government officials who can formulate key policies, Watanabe said.

“Now Trump looks willing to listen to what Abe says,” he said. “I don’t think Abe is simply trying to get into line with Trump.”