Kim Jong-un sent another chilling message to the civilized world with his ICBM launch on Friday, the longest yet and the second to pass over Japan. That prompted international condemnation and a chorus of calls for the Trump administration to put more pressure on China to rein in its longtime ally in Pyongyang (although Beijing did denounce the launch).

But it's increasingly clear we may be forgetting another culprit behind North Korea's missiles, namely Moscow — starting with the engines that power them.

The key clue came back with North Korea's first test launch of its newest ICBM, back on July 28. "It shocked me," former Pentagon consultant Michael Elleman told the Washington Post after seeing the video. "It seemed to come out of nowhere."



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Not only did the new missile, the Hwasong-14, give the regime for the first time a missile capable of striking most of the U.S. and Canada; Elleman also noticed that its liquid-fuel engines are very similar to a 1960s-era Soviet missile called RD-250. How did the North Koreans make these advances so quickly?



They may be getting direct help from Vladimir Putin.



Ties between Moscow and Pyongyang go back to the earliest days of the Cold War. Soviet T-34's spearheaded Kim's grandfather's invasion of South Korea in 1950. Yet while the international concern about North Korea's missile and nuclear programs have led almost every other country to distance themselves from the Pyongyang regime, Moscow has discreetly increased its ties. Russian imports are an important support for the North Korean economy; in 2014 Putin canceled 90 percent of the DPRK's $11 billion debt to Russia; and when China halted its energy exports to North Korea, Putin stepped into the gap.



Russian support for Pyongyang has long included propping up its nuclear program with technical cooperation, including letting North Korean nuclear scientists work at Russian nuclear sites and its scientific academies as recently as 2015.



Now Moscow may be giving Kim's missile program a more substantial boost.



When Pyongyang began the latest battery of tests of missiles last May, Russia launched a new ferry service from the Russian port city of Vladivostok to the North Korean port of Rajin — again, a strange thing to do when the rest of the world was shutting down contact with the Hermit Kingdom. The ferry Mon Gyong Bong is billed as a cargo and passenger venture and is operated by a Russian-owned company based in North Korea. All the same, Rajin is only twelve hours drive from Kusong, the site of North Korea's IRBM on May 14. On July 4, barely a month after the ferry began service, North Korea launched the second of its unexpectedly sophisticated missile launches. In fact, the more trips the Mon Gyong Bong made, the faster North Korea's nuclear-missile program grew.

For example, the Vladivostok-to-Rajin ferry shuttled unknown cargos on at least nine round trips until July 14, when Russian customs officials suddenly announced they were detaining the Mon Gyong Bong for 16 hours on suspicion it might be carrying cargo for North Korea's military. The ferry was released the next day; no one knows if any cargo was taken off, or if any additional cargo was put on.



Then 13 days later, North Korea shocked the world again with its Hwasong-14 ICBM, powered by what Elleman and other analysts concluded looked like Soviet-made RD-250 rocket engines. "It appears that they sourced that engine from a foreign entity and they have successfully incorporated that engine into their missiles," said Elleman. A story in the New York Times said that the foreign entity might be Ukraine, which used to make RD-250s during the Soviet era. Ukraine's State Space Agency, however, is adamant that the Ukrainian-made RD-250s of the kind used in the July 28 test were sent to Russia for its Tsyklon space rockets by the hundreds — while Ukraine itself has been a staunch supporter of sanctions against North Korea.



To deepen the mystery, U.S. intelligence agencies believe North Korea has the capacity to manufacture its own liquid-fuel rocket engines without Russian help. Nonetheless, the speed with which Kim was able to ramp up his missile program this summer still leaves serious questions about Russia and the Mon Gyong Bong.

In their 2014 book North Korea: The Politics of Regime Survival, Young Whan Kihl and Hong Nack Kim noted that "some restricted arm and weapons material have reached North Korea from Russia. . . . Russian companies have been among the suppliers of North Korea's nuclear program." Now Putin may be covertly supplying its missile program as well.

The key question is why Putin would exacerbate an already crisis-level situation on the Korean peninsula. The answer may be the same as to why Putin has embroiled Russia in Syria: as a way to disrupt and distract the West, especially the United States, and to make Kim Jong-un a Putin client like Syria's Assad, a dictator who becomes completely dependent on Moscow for his regional status, even his survival, and will do Moscow's bidding.



As I've noted in my previous articles for NRO, the best short-term solution to the North Korean missile threat is intercepting an attack with a high-altitude, long-endurance UAV armed with interceptor missiles. However, because of missile trajectories, if a UAV shoots down a nuclear-armed ICBM headed for the U.S. in its boost phase, the debris will almost certainly fall on Russian territory.



If that happens, it seems Putin will have no one to blame but himself.



Commentary by Arthur Herman, a senior fellow at the Hudson Institute and the author of Douglas MacArthur: American Warrior. Follow him on Twitter @ArthurLHerman.

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.

©2017 National Review. Used with permission.