Russian President Vladimir Putin and North Korean leader Kim Jong-un at a dinner reception in Pyongyang on June 19, 2024. / News1

“North Korea-Russia relations are evolving into a blood alliance involving mutual military assistance,” South Korea’s Defense Intelligence Agency (DIA) reported to the National Assembly on Oct. 30. “We believe North Korea will seek Russia’s advanced military and space technologies and attempt to modernize its conventional forces,” the agency said. North Korea’s Minister of Foreign Affairs, Choe Son Hui, arrived in Moscow on this day following reports that Pyongyang has sent thousands of troops to Russia to fight against Ukraine. She is expected to discuss the terms of this deployment with Russia.

Former White House senior adviser and CIA veteran Dennis Wilder highlighted the risks associated with North Korea’s potential acquisition of nuclear-powered submarines and ICBM re-entry technology. “If North Korea’s nuclear-powered submarines were to roam the Western Pacific, it would be an enormous problem for all of us.” For South Korea, however, this scenario is more than a headache—it is a serious security threat.

In September last year, North Korean leader Kim Jong-un unveiled a tactical nuclear submarine with underwater strike capabilities and has made it clear that the navy’s nuclear armament is “an urgent task.” While North Korea possesses underwater-launched nuclear missiles, it lacks nuclear-powered submarine technology. If Russia provides North Korea with this technology, it would allow North Korea to hide nuclear missiles in submarines with unlimited underwater capabilities. It would be a disaster for the South.

If Kim Jong-un acquires nuclear-powered submarines and the U.S. finds itself unable to fully intercept North Korea’s nuclear missiles, Washington may be forced to reconsider its stance toward Pyongyang. The U.S. could potentially recognize North Korea’s nuclear capabilities, partially lift sanctions and move toward managing the risk rather than eliminating it. This scenario, too, would be disastrous for South Korea.

The DIA also noted that “North Korea is likely to conduct another ICBM launch in November.” North Korea has yet to launch an ICBM at a standard angle and range, leading to the assumption that Pyongyang lacks re-entry technology. But if Moscow provides ICBM re-entry technology to Pyongyang, North Korea’s nuclear missile capabilities would be complete, creating the conditions for North Korea to negotiate a “nuclear disarmament” deal with the U.S.

Kim Jong-un would not send over 10,000 North Korean troops to perilous combat zones for nothing in return. Russian President Vladimir Putin is the one under pressure, facing more than 600,000 casualties from Russia’s aggression against Ukraine. He could agree to Kim’s demands by offering advanced weapons such as nuclear-powered submarines, ICBM re-entry technology, or the latest fighter jets as a compromise. Yet such a decision would signal a deliberate hostility toward South Korea. Should Russia cross this “red line,” South Korea would have no choice but to take emergency countermeasures.