In 2025, Choong-Koo Lee wrote, “Putting the Screws on the Partnership Between North Korea and Russia,” where he argued that the United States and South Korea should work together to weaken Pyongyang and Moscow’s military relationship. A year later, we asked him to revisit his arguments.Image: The Kremlin via Wikimedia CommonsIn your 2025 article, you argued that the United States and South Korea should work together to limit the deepening military relationship between Russia and North Korea. How has the U.S.-South Korean relationship evolved over the past year, and what does that mean for the prospects of any joint effort? Separately, do Russia and North Korea have any real incentive to scale back their military cooperation?With the beginning of the second Trump administration, Seoul and Washington had to first readjust their trade and defense-related relations, rather than focus immediately on the growing challenge posed by Russian-North Korean military cooperation. To address the tariff issue raised by President Donald Trump in March 2025, Washington and Seoul reached an agreement after months of negotiations in late July: South Korea would invest $350 billion in the United States, while Washington would lower the tariff rate to 15 percent. Because this investment is also expected to support U.S.-South Korean cooperation in shipbuilding, it could further enhance the strategic value of the alliance. Furthermore, at the U.S.-South Korean summit in October, Trump stated that he had approved South Korea’s nuclear-powered submarine construction project.In my earlier article, I also argued that because Russian-North Korean military cooperation could continue to advance despite U.S.-South Korean efforts to restrain it, Seoul and Washington would need to strengthen military cooperation in strategic domains, including undersea warfare and missile defense. In that regard, the recent U.S. support for South Korea’s nuclear-powered submarine capability could provide a military option against a future scenario