He is the reigning bad boy of global affairs, a nemesis of American presidents and an antagonist who flouts international borders and diplomatic protocols.

So how did Vladimir Putin come to be the voice of calm in the storm?

In the furious debate over how to subdue a defiant Kim Jong-un, it has fallen to the strongman Russian leader to take up the cause of peace in a volatile region and rational thought in a time of discourse tainted with madness. Indeed, South Korean President Moon Jae-in even personally begged Mr. Putin this week to "tame" Seoul's northern neighbour.

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Mr. Putin, in turn, has struck a tone of prudent equanimity, decrying North Korea's recent test of what is believed to be a hydrogen bomb while also explaining the diplomatic quagmire that has enveloped the country's pursuit of deadly weapons.

"They would rather eat grass than give up their nuclear program," he said this week, later explaining that Pyongyang sees the idea of freezing its nuclear development as "an invitation to the cemetery." The situation has brought the world perilously close to "catastrophe," he warned, while also offering optimism. "I am sure that things will not go as far as a large-scale conflict, especially with the use of weapons of mass destruction." He added: "We can solve this problem through diplomatic means."

The flurry of comments followed his foreign minister's earlier expression of sympathy for the little guy in North Korea, a rare nod to the well-being of its 25 million people: In August, Sergei Lavrov accused the United States of aiming for "the economic strangulation" of the country, and "all the negative consequences" that would entail.

What is Mr. Putin, a man better known for stoking anger than quenching it, up to?

In U.S. policy circles, the answer is obvious. He is, once again, looking for ways to embarrass the White House.

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"He is, I'm sure, delighted in tweaking the United States," said Brad Glosserman, executive director of the Pacific Forum of the Center for Strategic and International Studies. "He's a spoiler, without question."

But Mr. Putin's sudden prominence may also indicate a more serious shift, presaging a rupture in the international community's unified front on pressing North Korea to back down.

For the past year, Russia and China have surprised observers with their willingness to co-operate with the United States on a set of progressively stricter sanctions, the latest of which cut off key sources of North Korean income through exports of minerals and seafood.

Now, as the United States seeks to inflict much sharper pain by cutting off North Korea's oil imports and textile exports, Mr. Putin's warnings suggest he has concluded that his interests and those of U.S. President Donald Trump are diverging.

Washington wants North Korea to give up its nuclear weapons and is willing to destabilize Pyongyang to achieve its ends. Moscow, Mr. Putin is signalling, would prefer to live with a new nuclear-armed neighbour than watch chaos erupt in the small, distant corner where Russia shares a border with North Korea.

"For Russia and China, the North Korea nuclear program is an indirect threat. But an outbreak of violence and regime collapse in North Korea is likely to be a direct threat," said Andrei Lankov, a Russian-born expert on North Korea at Kookmin University in Seoul.

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It's tempting to see Mr. Putin as a natural bedfellow with Mr. Kim – two authoritarian leaders gleefully tweaking Mr. Trump and causing him to lose political face. There is, however, little love between modern Russia and North Korea, Prof. Lankov said.

"Like pretty much all Russians of his generation, Putin despises Kim Jong-un. He sees him as a crazy comical despot of a tiny country," he said. "But it's irrelevant whether he likes Kim Jong-un or not. It's not what he cares about now. He cares about preventing a civil war on the Russian border."

Though Russia has long been involved in international discussions on North Korea, Mr. Putin's willingness to speak out is unlikely to indicate a new-found ability to mediate the ongoing crisis, which has created jitters in financial markets and raised the spectre of nuclear war.

"I am not sure at all that Russia's role in managing this crisis is meaningful. Putin is certainly trying to boost his profile, but it is – from what I can see – mostly appearances," added Pavel Baev, a research professor at the Peace Research Institute Oslo who is an expert on Mr. Putin's military and economic strategy.

Mr. Putin, too, has yet to propose anything unique. His call for a "freeze for freeze" – a U.S. halt to joint military exercises with South Korea in exchange for a North Korean stop to nuclear and missile testing – is an echo of a Chinese proposal.

"Ultimately nobody else can do much here except the North Korean diplomats and the American diplomats. That's where the game is – and all the rest of the noise, both the military noise, which is just pure blather at this point, and all the talk about sanctions, is just irrelevant," said Leon Sigal, director of the Northeast Asia Cooperative Security Project at the Social Science Research Council in New York.

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North Korea may have thermonuclear technology. But if talks take place, negotiators can still hope to halt expansion of the regime's weapons stockpile, he said.

On the U.S. side, however, it's possible that there are strategic calculations in suggesting an oil embargo that others – both Russia and China – may not support.

"China is unlikely to support any sanctions that could seriously destabilize North Korea or really cause severe, long-term damage to the North Korean economy. An oil embargo, if properly enforced, surely would do the latter," wrote Benjamin Katzeff Silberstein, an associate scholar at the Foreign Policy Research Institute who writes the North Korean Economy Watch.

The United States could then use Chinese refusal to support such a ban "as leverage for expanded secondary sanctions against Chinese entities trading with North Korea."

Still, Chinese experts cautioned against prematurely concluding that North Korea's neighbours will block all forms of an oil embargo.

"I personally think if this had to be implemented it would have to be temporary, done to a limited degree, or run as a trial," said Lu Chao, a North Korea expert at China's Liaoning Provincial Institute of Social Science.

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But any such ban, he said, should not "lead to the failure of the regime, or disintegration of the country."