Cho Chang-rae, left, South Korea's deputy defense minister for policy, shakes hands with Vipin Narang, U.S. principal deputy assistant secretary of defense for space policy, after signing a framework document on the Nuclear Consultative Group at the Pentagon in Washington, D.C., Monday (local time). Courtesy of Ministry of National Defense

Wary of the potential return of former U.S. President Donald Trump to the White House this year, the defense ministries of South Korea and the United States signed a framework document on the Nuclear Consultative Group (NCG), a collaborative mechanism established between the two allies to discuss and coordinate nuclear policy, security, and defense.

The move appears to be aimed at expediting the full implementation of the nuclear coordination agreement previously signed by South Korea and the U.S. to strengthen Washington's extended deterrence against the growing nuclear threat from Pyongyang.

With Trump emerging as the leading Republican presidential candidate, concerns are mounting over the potential impact of his reelection on the strengthened security commitments that the Biden administration pledged to Seoul.

South Korea's Deputy Defense Minister for Policy Cho Chang-rae and U.S. Principal Deputy Assistant Secretary of Defense for Space Policy Vipin Narang signed the document at the Pentagon in Washington, D.C., Monday (local time), according to Seoul's defense ministry, Wednesday.

The document outlines the specific goals of the NCG based on the April 2023 Washington Declaration signed between President Yoon Suk Yeol and U.S. President Joe Biden, the ministry added. Launched in July 2023, the NCG is a consultative body designed to discuss the enhancement of U.S. extended deterrence through joint nuclear planning to counter North Korean nuclear threats.

Based on the newly-signed document, Cho and his U.S. counterpart will spearhead efforts to fully establish guidelines regarding the planning and operation of nuclear weapons by the first half of this year.

"The fact that the framework document was signed between defense ministry officials, not officials from the presidential office and the White House, indicates that the allies have apparently opted to shift NCG discussions to the ministerial level, considering that interactions between presidential officials may weaken in the event of Trump's reelection," said Park Won-gon, a professor of North Korean studies at Ewha Womans University.

The NCG has conducted two meetings so far. The inaugural meeting took place in Seoul in July 2023, and the second was held in Washington in December that year, both involving Principal Deputy National Security Adviser Kim Tae-hyo and then White House Indo-Pacific coordinator Kurt Campbell.

The third meeting scheduled for June in Seoul will be organized by the defense ministries.

Kim Sung-han, a former top security adviser to Yoon, said during a forum earlier this week that South Korea maintains an open-minded stance regarding Japan's potential participation in the NCG. Kim added that he had discussed the matter with Japanese officials during his tenure.

His remarks are also interpreted as a strategy to uphold the current NCG framework in case Trump returns to the White House.

Republican presidential candidate and former U.S. President Donald Trump gestures to the audience as he leaves a rally at Coastal Carolina University in Conway, S.C., Saturday. AFP-Yonhap

During a campaign rally in South Carolina last week, Trump said he would "encourage" Russia to do whatever it wants to NATO countries that are "delinquent." His remarks prompted a strong backlash from European leaders.

Park viewed that Trump's skepticism about military alliances extends to Asian allies as well, suggesting that if elected, he could be reluctant to carry out the agreement reached through the Washington Declaration.

"While Trump is unlikely to completely abandon the agreement, he could be skeptical about core aspects of the Washington Declaration, such as the regular deployment of U.S. strategic assets on the Korean Peninsula and joint military exercises based on conventional-nuclear integration (CNI), " Park said, noting Trump's previous pledge to cease joint drills with South Korea, referring to them as "war games."

However, Yang Uk, a defense analyst at the Asan Institute of Policy Studies, gave a different analysis.

"Although Trump considers military alliances burdensome and would demand increased contributions from allies, there is a growing opinion among Republicans that the U.S. should prioritize stronger extended deterrence, while reducing conventional weapons and the deployment of military troops," Yang said.

In that regard, the analyst anticipated that Trump is unlikely to scale back the Biden administration's strengthened commitment to extended deterrence for South Korea. Instead, he could once again threaten to reduce the number of U.S. Forces Korea (USFK) troops to pressure Seoul to cover more defense costs.