The article discusses the growing debate in South Korea about the country's need for its own nuclear weapons, as decades of American assurances have failed to deter North Korea from building a nuclear arsenal. President Biden's commitment to defend South Korea with nuclear weapons has not eased concerns, especially with the potential re-election of former President Donald J. Trump, whose commitment to the alliance between Washington and Seoul appears uncertain. A growing majority of South Koreans now believe their country needs its own nuclear weapons instead of relying on the United States for protection. Despite this, South Korea lacks the facilities and technical know-how to pursue atomic weapons. The article also highlights concerns about the future of the South Korea-U.S. alliance, especially if Mr. Trump is re-elected, as he has previously expressed openness to allowing Japan and South Korea to build their own nuclear arsenals.