Japanese Prime Minister Shinzo Abe, right, meets with Shigeo Iizuka, second from right, leader of a group of families of Japanese abducted by North Korea, and Sakie Yokota, second from left, mother of Megumi Yokota, one of the Japanese abductees and other members in Tokyo in March. (Toru Hanai/AP)

As North Korean leader Kim Jong Un works the diplomatic channels from Seoul to Washington, one Asian leader finds himself out in the cold.

Japanese Prime Minister Shinzo Abe has repeatedly expressed his determination to meet Kim and “break the shell of mutual distrust.” So far there is nothing on the horizon.

Just the opposite, in fact.

North Korea’s propaganda machine has gone easy on the United States this year. But it has stepped up its vilification of Japan, sparing no opportunity to remind its citizens of Korea’s suffering under Japanese colonial rule in the decades before World War II.

Japan, North Korean state media argues, is nothing less than “heinous war criminal state,” populated by “island barbarians” and led by a “kingpin of corruption” who has done only evil deeds since taking power.

The question is whether all that bluster matters. After all, the North had blasted the United States with a similar propaganda barrage for decades.

But the fast-moving events this year have highlighted Japan’s outlier status as possible deals are cut and new relationships are formed.

“There is a real danger that Abe’s Japan is going to get left behind,” said Koichi Nakano, a political-science professor at Tokyo’s Sophia University. 

The Japanese news media took a similar line this week, reacting coolly to the exultant mood at the summit between Kim and South Korean President Moon Jae-in. 

Nikkei, an influential financial newspaper, painted a “worst-case scenario” in which North Korea gives up its intercontinental ballistic missiles but retains the ones that can target Japan.

“Cooperation between Japan, the United States and South ­Korea is essential,” a Nikkei article said.

Last year, Japan stood side by side with the United States in insisting on “maximum pressure” on North Korea until the country surrenders its nuclear weapon program.

Today, “maximum pressure” has all but disintegrated, as China and Russia ease their enforcement of sanctions and South Korea talks eagerly about economic cooperation with the North.

So, when Japanese Foreign Minister Taro Kono warned recently that sanctions should not be lifted until North Korea completely denuclearizes, Pyongyang reacted with contempt. It mocked Tokyo for trying to stand in the way of the “trend of the times.”

“It has been left alone in the region, being branded as a country of pigmy politicians ­engaged in abnormal view on things and phenomena, anachronistic thought and stupid and unbecoming conduct,” the North’s official Rodong Sinmun newspaper wrote.

“Japan will be left alone forever as a lonely island country if it persistently behaves like Don Quixote,” it added.

North Korea had built a regime of fear based on the idea that a U.S. invasion is imminent, and its television news takes every opportunity to remind viewers of the terrible atrocities it says were committed by the U.S. military during the Korean War.

That is, until Kim prepared to meet with President Trump in Singapore in June.

Anti-American propaganda has largely vanished from state TV and news media, and Trump is no longer described as “mentally deranged” or a “dotard.” Instead Japan has assumed the mantle of Public Enemy No. 1. 

Partly that’s because the regime needs a scapegoat for its own repressive rule, and Japan is an easy target. It is also because Pyongyang sees Tokyo as an American puppet, not worth taking seriously at this stage in the negotiating process — even if it wants Japanese cash and investment further down the line, experts say.

But there is another reason Tokyo finds itself on the sidelines: the “abductions issue.”

In the 1970s and 1980s, an unknown number of Japanese citizens were kidnapped by North Korean agents and taken to North Korea, partly to teach spies about Japanese language and culture. 

The issue has inflamed public opinion ever since and become a favorite cause for conservative Japanese politicians, who still wear blue-ribbon lapel badges in solidarity with the affected families. And the man who championed that cause more than any other — and who rose to political power partly on the back of it — is Abe himself.

In 2002, Junichiro Koizumi, then Japan’s prime minister, traveled to Pyongyang and managed to get five abductees released. Japan says at least 12 more remain missing and rejects North Korea’s assertion that no more are left alive and that the case is closed. Since 2002, both sides have dug in their heels.

Such is the sensitivity of the issue that Abe could meet with Kim only if there were a strong indication that North Korea was prepared to meaningfully reopen the conversation about the abductees, said Jenny Town, a Korea specialist at the Stimson Center in Washington. 

In the meantime, she said, Japan finds itself “the benchwarmers” in North Korean diplomacy, “at the end of the line, not going to be called on anytime soon.”

“In a sense, Abe has boxed himself in,” said Chris Hughes, a professor of international politics and Japanese studies at the University of Warwick in Britain. “The Japanese government have built a position that is a little hard to pull back from.”

To make matters worse, there is urgency. The father of one of the Japanese missing — Megumi Yokota, who was 13 when she was abducted — is ill. Her mother writes heartfelt letters to her long-lost daughter that are periodically published in the Sankei Shimbun newspaper.

Nevertheless, negotiations are likely to be going on behind the scenes, Hughes said. The Washington Post reported on one secret meeting between Japanese and North Korean officials in Vietnam in July. 

And experts don’t rule out the possibility of progress.

Sheila Smith, a senior fellow for Japan studies at the Council on Foreign Relations, notes that Kim contacted Abe in 2014 about the abductee issue. The initiative foundered but could potentially be revived, she said.

Hitoshi Tanaka, who led secretive negotiations with Pyongyang during the Koizumi admin­istration, said Tokyo is unlikely to resolve the abductee issue straight off.

Instead, it needs to support U.S.-led efforts to get North Korea to denuclearize, he said, and then arrange a credible investigation into the abductee issue as part of a broader deal that includes Japanese investment and aid.

“To resolve this issue, we have to be very scientific, we have to be coolheaded,” he said.

In the meantime, Abe finds himself in a tough spot. 

Sophia University’s Nakano argues that is largely his own fault.

“His strategy was to ally strongly with the United States and present himself as the loyal sidekick in Northeast Asia facing China and North Korea,” he said. “But when Trump decided otherwise, he was badly wrong-footed. He is still living with the consequences, trying to make himself relevant again in the geopolitics of Northeast Asia.”

Akiko Kashiwagi in Tokyo and Min Joo Kim in Seoul contributed to this report.