South Korea has long relied on the United States to keep the North Korean nuclear threat at bay. Pyongyang began taking fitful steps toward a nuclear weapon during the Cold War, tested its first bomb in 2006, and today regularly issues nuclear threats against its southern neighbor. Seoul, meanwhile, shelters under the American nuclear umbrella that came with the defense alliance it signed with Washington in 1953, just after an armistice effectively ended the Korean War. For decades, this arrangement provided South Korea sufficient security assurance. But today, that assurance appears increasingly fragile.
The United States has lost credibility and is no longer seen as a reliable ally, whether in Asia, Europe or the Middle East. American foreign policy is increasingly perceived as weak, unreliable and biased.
South Korea’s problem is twofold. First, North Korea’s capabilities are growing. Pyongyang has developed an intercontinental ballistic missile, which raises doubts about whether the United States would honor its alliance commitment and fight for South Korea, because North Korea can now strike American cities with a nuclear weapon. Secondly, Donald Trump, who has severely criticized the U.S.-South Korea alliance in the past, has entered his second term as U.S. president. Under Trump, the likelihood of Washington intervening in a conflict on the Korean peninsula will diminish further. The USA is now more concerned about China’s military might, which will overtake the USA in a few years’ time.
Under these conditions, some experts believed that the bomb is the best way to contain the threat from the North. That is the fundamental argument for South Koreans who want their country to develop its own nuclear weapons. It’s about the need to protect themselves from an aggressive northern neighbor that is already a nuclear power in all but name and whose leader Kim Jong Un has vowed an “exponential increase” in his arsenal.
The counter-argument, which has has long stopped Seoul from pursuing the bomb, lies in the likely consequences. Developing nukes would not only upset the country’s relationship with the United States, it would likely invite sanctions that could strangle Seoul’s access to nuclear power. And that is to say nothing of the regional arms race it would almost inevitably provoke. But which side of the argument South Koreans find themselves on appears to be changing.
Read more on June 1st, 2025.