The U.S. Department of Energy headquarters in Washington is seen in this photo taken Feb. 18. UPI-Yonhap

South Korea faces a critical diplomatic challenge as it seeks to overturn the U.S. government's decision to designate it as a "sensitive country" in the energy sector, a move that analysts warn could strain bilateral ties.

Caught off guard by the decision by the U.S. Department of Energy (DOE), South Korea now has less than a month to reverse the move before it takes effect on April 15. While officials in Seoul are scrambling to figure out the rationale behind the designation, they also face the challenge of persuading the Donald Trump administration to undo the policy, which had been put in place near the end of the Joe Biden administration.

"The previous administration added the Republic of Korea (ROK) to the lowest category (Other Designated Country) of the sensitive and other designated countries list in early January 2025," a DOE spokesperson was quoted as saying by Yonhap News Agency, Saturday, referring to South Korea by its official name.

"Currently, there are no new restrictions on bilateral science and technology cooperation with the ROK. The Energy Department looks forward to collaborating with the ROK to advance our mutual interests," the spokesperson added.

Although the rationale behind the DOE's decision remains unclear, analysts suggest that Washington may be concerned about the growing calls within South Korea to develop its own nuclear weapons. Some conservative politicians and researchers in the country have been advocating for Seoul to pursue nuclear capabilities, or at least enhance its existing ones, amid increasing skepticism about the reliability of U.S. extended deterrence.

Lee Chun-geun, an honorary fellow at the Korea Institute of Science & Technology Evaluation and Planning, described the designation as a warning from the U.S. against such calls.

"If you look at the DOE list, other than traditional adversaries like Iran, Russia and China, there are two U.S. partners — Taiwan and Israel. Now, South Korea joins them. What do these three countries have in common? Growing debates about obtaining nuclear weapons," he told The Korea Times.

President Yoon Suk Yeol walks with then-U.S. President Joe Biden at the Rose Garden of the White House, April 26, 2023. UPI-Yonhap

"The energy department, which oversees the production and management of nuclear materials, is highly sensitive to nuclear nonproliferation. This decision would have been the result of careful deliberation and information gathering over several months about related discussions in Seoul."

According to the DOE website, a "sensitive country" requires "particular consideration for policy reasons, including national security, nuclear nonproliferation, regional instability, threats to national economic security or support for terrorism."

Once the designation takes effect, it could limit South Korea's participation in advanced technology sectors such as nuclear energy and artificial intelligence. It may also lead to stricter certification procedures for South Korean researchers entering DOE facilities or participating in joint projects.

Yang Moo-jin, president of the University of North Korean Studies, warned that the decision could have broader implications beyond bilateral relations.

"With Trump calling North Korea a 'nuclear power' while designating South Korea as a sensitive country on nuclear energy, this could weaken Seoul's leverage in future denuclearization talks," he said.

Foreign ministry spokesperson Lee Jae-woong speaks during a press briefing at Government Complex Seoul, Friday. Yonhap

A foreign ministry official stated that the ministry is "actively engaging in negotiations to prevent any negative impacts on energy and science and technology cooperation between the two countries" and will continue high-level engagements with relevant U.S. agencies.

The ministry added that it was aware of the designation before it was made public last week, noting that the information had been shared through unofficial channels.

Analysts say reversing the decision will be difficult, especially as key diplomatic engagements with the Trump government have being delayed.

U.S. Defense Secretary Pete Hegseth is expected to visit Asia soon, but a stop in South Korea appears unlikely due to the suspension of President Yoon Suk Yeol from his official duties after the National Assembly passed an impeachment bill in December over his Dec. 3 martial law declaration. Foreign Minister Cho Tae-yul has been attempting to visit Washington since Trump's inauguration, but that trip has yet to take place.

"Negotiating with the Trump administration requires high-level engagements, but the current acting leadership's limited capabilities make this difficult. The best course of action would be to reaffirm Washington on our commitment to nuclear nonproliferation," Yang said.

Rep. Kweon Seong-dong, second from right, floor leader of the ruling People Power Party, speaks during a press conference at the National Assembly in Seoul, Sunday. Yonhap

Blame game

Rival parties have pointed fingers at each other over South Korea's potential listing as a sensitive nation.

The main opposition Democratic Party of Korea (DPK) criticized the move as a "diplomatic blunder," citing rising calls from conservative politicians for the nation to acquire nuclear weapons.

"Previous remarks made by President Yoon Suk Yeol regarding nuclear armament, along with similar calls from key ruling party figures, which were baseless and lacked substance, have significantly heightened tensions, and we see this as the decisive reason," DPK spokesperson Rep. Jo Seung-lae said Sunday.

Meanwhile, the ruling People Power Party (PPP) argued that it is too early to determine the exact reason behind the U.S. move, while shifting the blame to the opposition's impeachment drives.

"Realistically, in a situation where both the president and the prime minister are suspended from their duties, it is difficult to respond quickly to diplomacy and trade issues under the acting leadership," PPP floor leader Rep. Kweon Seong-dong said.