The Russia–South Korea Relationship after Russia's Invasion of Ukraine and Implications for the U.S.-ROK Alliance

executive summary:This essay examines the potential for shifts in Russia's strategy toward the Korean Peninsula in light of Russia's full-scale invasion of Ukraine and South Korea's reaction.main argumentFor nearly 30 years, Russia has pursued a strategy of "diplomatic equidistance" toward the Korean Peninsula. By striving to maintain relatively balanced ties with both North and South Korea, the Kremlin has attempted to preserve a degree of influence on its eastern periphery in Northeast Asia, which is largely dominated by the U.S. and China. Pyongyang's and Seoul's respective responses to Russia's military aggression in Eastern Europe, however, have opened the possibility that Moscow could shift toward a strategy that favors North Korea over South Korea.policy implications• Should Russia decide to pursue closer ties with North Korea at a time when Russia–South Korea relations have cooled, the Kremlin may find that supporting the North could increase its influence in Northeast Asia as well as present a challenge to the U.S. Nevertheless, Moscow would also risk losing the limited influence on the Korean Peninsula it has acquired as a result of its equidistance strategy.• South Korea faces a period of uncertainty in relations with Russia since the invasion of Ukraine. While it is unlikely that Moscow and Seoul will enact the economic cooperation that they had previously envisioned, South Korea may hope to salvage ties with Russia to improve the balance on the Korean Peninsula. Yet with increased fears that North Korea–Russia relations may strengthen, South Korea has reason to be skeptical of cooperation.• The U.S. will need to be prepared for several possible developments in terms of Russia's standing on the Korean Peninsula. Should South Korea elect to try to preserve cooperation with Russia, this may cause a further rift in the U.S.–South Korea alliance. If Moscow doubles down on its relationship with Pyongyang, Seoul and Washington will need to be prepared to jointly address such a development with implications for the Northeast Asian subregion and Russia-U.S. ties.