(CNN) A summons from Beijing brought North Korean leader Kim Jong Un out of isolation into his first foreign foray since taking power. This week, his foreign minister is visiting Moscow to meet with Russia's top diplomat, Sergei Lavrov.

From years of isolation to sudden and rapid all-out engagement, the North Korean leadership continues to travel the world. Its envoys shuttle between world capitals , meeting with diplomats and attempting to shore up alliances for the Hermit Kingdom in the lead up to an historic summit with US President Donald Trump.

The latest breakthrough came on Tuesday, when Lavrov announced he had accepted a formal invitation to visit Pyongyang after a meeting with North Korean Foreign Minister Ri Yong Ho in Moscow.

Lavrov said Moscow wanted to develop "good neighborly relations" with North Korea, according to Russian state media TASS.

"We are very happy about the invitation which we have received to visit Pyongyang," Lavrov said.

"October will mark 70 years since our countries established diplomatic relations and now our colleagues are agreeing on a program of measures to celebrate this jubilee," Lavrov said, adding that Russia would continue "humanitarian assistance" to North Korea.

Bruce Bechtol, a professor of political science at Angelo State University who has authored several books on North Korea, said Kim had sent his envoy to Russia because Moscow is the only government "that has a semblance of being an ally besides China."

"This is about getting Russia on board with them to take their side as the North Koreans walk into talks, not just with us, but with the South Koreans as well," Bechtol told CNN.

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From self-reliance to sanctions

Since its founding, North Korea has promoted the ideology of "juche," or "self-reliance." It was the creed hammered into the national psyche after the armistice of 1953 sent the Hermit Kingdom into self-imposed exile from the world. It has been drummed into the minds of North Koreans that they are outsiders, underdogs, and the ultimate survivors.

But the first signs that such self-reliance may not be enough for the country to endure punishing sanctions came at the beginning of this year. In January, Kim Jong Un offered to hold talks with South Korea , first over his country's participation in the Winter Olympics, and later to discuss the denuclearization of the Korean peninsula.

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Retired US ambassador William Courtney said the added unpredictability of the US president has also thrown the North Koreans.

"Trump has been quite open that he wants to put maximum pressure on North Korea. The US and South Korea are carrying out their annual exercises, and now we have the addition of the promotions of John Bolton and Mike Pompeo," said Courtney, who is now is an adjunct senior fellow at the RAND Corporation.

"Those are two people who are known to be hardliners on North Korea, so my guess is North Korea's more open posture is a direct result of the pressure from the Trump administration and Trump personally," Courtney said.

"The North Koreans are probably concerned that the United States is preparing scenarios of military force."

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Russia's North Korean dilemma

The date for the Trump-Kim summit has not yet been announced, but there has been an open channel for North Korea and the US to communicate via regarding the summit and the logistics involved.

Trump already has to take into account China's influence and position on North Korea, the question is now whether he will have to consider Moscow's view as well.

"Russia has far less influence or leverage with North Korea than China does, and that's not because of the military stuff, it's purely because of money," said Bechtol, the academic.

"During the Cold War, Russia subsidized everything in North Korea . North Korea was not a poor country, it was simply a subsidized member of what we can now call the Soviet Union's satellite states."

That all ended in 1991, said Bechtol, when the Berlin Wall came down, communism in the Soviet Union and its member states collapsed, and Russia opened its economic doors to the West.

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North Korea's economy took a dive after that, and the withdrawal of food subsidies in the early 1990s from both China and the Soviet Union, the failure of the regime's collective farming policies, and flooding followed by a disastrous drought, all led to food shortages and a subsequent famine that killed two to three million North Koreans.

But recently, Russia has been making inroads to counter China's perceived clout with North Korea.

Russia forgave Pyongyang's Soviet-era debt , writing off $10 billion, and Russia, alongside China, is now one of the largest food donors to North Korea. Among the many sanctions Russia is facing are US Treasury penalties for selling oil to the North Korean regime.

For Russia, North Korea is a complex problem, said Ambassador Courtney.

"The North Korean regime likely wants to show that not only does it have support but make a show of building support from these high-level visits," he told CNN.

"For Russia, it's already overtaxed with Ukraine and Syria and the Skripal poisoning , so it doesn't really need another foreign policy crisis right now. And Russia would like the focus on China rather than on itself."

He was referring to the poisoning of Sergei Skripal in Salisbury, in the UK. London and its allies have blamed the Kremlin for the attack and deported dozens of Russian diplomats in retaliation.

At the same time, some observers argue the North Korean foreign minister's visit to Moscow may also be laying the groundwork for a meeting between Putin and Kim.

In March 27, China's President Xi Jinping met North Korean leader Kim Jong Un in Beijing.

Engagement policy on steroids

Kim Jong Un is following the playbook of his father Kim Jong Il, by alternating "provocations with charm offensives in order to gain economic benefits and undermine international resolve on enforcing sanctions," said Bruce Klingner, a senior research fellow at the Heritage Foundation.

"Since January, Kim has put his engagement policy on steroids," he added.

Klingner said while Kim's behavior may reflect his father's, the unpredictability of Trump "makes it impossible to predict the outcome of the US-North Korean summit," adding that he expects Kim to try to "restore the lengthy, phased negotiating process of yore to buy time, gain benefits, and diffuse sanctions."

Other than signaling his approval of Kim's apparent interest in denuclearization, it's unclear what Trump's approach will be.

"I think the people advising President Trump ... have been telling him that when you walk into the talks with the North Koreans, do not give up any concessions until they first make their concessions and their number one concession is denuclearization on our terms," said Bechtol.

"That is to say, denuclearize your program and do it transparently, you do it under inspection and you do it completely, and unless or until that happens, the United States does not ease sanctions, we do not ease our state of readiness on the peninsula along with our troops and our Korean allies."

Bechtol added so far, the US policy of maximum pressure and economic sanctions has succeeded by bringing North Korea to the table, and that as long as that remains in place, and is strictly enforced, North Korea will have no choice but to yield, regardless of who else might be at that table too.