Washington (January 30, 2026) – Senators Edward J. Markey (D-Mass.) and Jeff Merkley (D-Ore.), co-chairs of the Nuclear Weapons and Arms Control Working Group, along with Senators Chris Van Hollen (D-Md.) and Ron Wyden (D-Ore.) today wrote to President Trump urging the strongest possible non-proliferation measures in any revised nuclear cooperation agreement with South Korea. The senators’ letter follows the White House’s release of a fact sheet on November 13 outlining the Trump administration’s plans to allow uranium enrichment and spent fuel reprocessing for peaceful uses in South Korea. The Trump administration’s action reverses long-standing bipartisan U.S. policy to prevent the spread of enrichment and reprocessing technologies to limit the risk that those capabilities could be used to produce fissile materials for weapons.
In the letter, the senators wrote, “South Korea’s complicated history with nuclear weapons, and your role in that history, makes your policy shift particularly concerning. South Korea has had an interest in nuclear weapons stretching back to the 1970s and conducted illicit activities that were investigated by the United Nations. In 2016, you suggested that South Korea should develop nuclear weapons. In 2024, the Biden administration designated South Korea a ‘sensitive country,’ a term used for states that pose a proliferation risk. At the time, the former South Korean President Yoon Suk Yeol was being impeached for declaring martial law. Yoon had suggested that South Korea may need to pursue nuclear weapons to deter North Korea.”
The senators continued, “Providing latent nuclear capability to South Korea would also undermine U.S. non-proliferation efforts. For example, the United States is currently negotiating a 123 agreement with Saudi Arabia, which has also expressed nuclear weapons aspirations and is also seeking to enrich uranium. As some of us wrote to your State Department on November 17, 2025, the Administration should apply the strongest ‘gold standard’ protections to prohibit enrichment and reprocessing in all nuclear cooperation agreements. Agreeing to weaker nonproliferation measures with South Korea would make it harder to hold the line on Saudi Arabia, undermining the existing global nonproliferation regime and exacerbating tensions across the Middle East.”
The senators request answers to the following questions by February 13, 2026:
- Does the Administration intend to revise its 123 agreement with South Korea? If so, what revisions will be made? Is the Administration seeking “gold standard protections”?
- Will the Administration inform the Senate Foreign Relations and the House Foreign Affairs committees about its intentions with respect to a revised 123 agreement with South Korea?
- What nuclear technology is the Administration planning to provide to South Korea, who will provide it, when will it be transferred, and under what terms?
- Is the United States considering constructing and operating enrichment and reprocessing facilities on South Korean soil?
- Who will build the nuclear-powered attack submarines, where will they be built, what type of fuel will they use, and where will that fuel be produced?