US President Joe Biden's seismic decision to drop out of the presidential race and endorse Vice President Kamala Harris as the Democratic nominee on Sunday has rattled South Korea.

The tectonic political shift raises critical questions about whether the steadfast South Korea-US alliance, exemplified by the Washington Declaration and the crucial trilateral cooperation with Japan highlighted at the Camp David summit, will endure despite Biden’s withdrawal.

Hours after Biden withdrew from the presidential race, the South Korean presidential office struck a cautious tone on his decision.

"We refrain from commenting on the internal political situations of other countries," a presidential official said on Monday on condition of anonymity.

"The support for the Korea-US alliance within the US is bipartisan, and our government will continue to work closely with the US to further develop the Korea-US Global Comprehensive Strategic Alliance."

Experts in Seoul explained on Monday that Biden's decision to drop out of the presidential race does not significantly impact US foreign policy concerning the US-Korea alliance now or in the future, despite potential minimal differences in approach.

They emphasized that if Harris secures the Democratic nomination, she is likely to uphold Biden's foreign policy objectives regarding the Korea-US alliance -- centered on the US extended deterrence commitment against North Korea -- and the trilateral cooperation among South Korea, the US and Japan.

"Although President Biden spearheaded these policies, their implementation was ultimately a collective effort by the entire Biden administration. Key figures who were instrumental in driving these initiatives remain in place," Cho Byung-jae, former chancellor of the Korea National Diplomatic Academy, told The Korea Herald.

"Vice President Harris was also part of this team, and so far, there has been no indication from the Biden administration that there will be any changes to these policies."

Kim Jin-a, a professor in the Language and Diplomacy Division at Hankuk University of Foreign Studies, noted that the "Washington Declaration has been followed by various institutional and procedural measures. The subsequent actions have made significant changes to it unlikely."

Kim also pointed out that the impact on foreign policy will be "minimal" compared to other domestic issues such as gender equality and abortion, areas where Harris has taken a more vocal stance, if she becomes the Democratic nominee.

More principled approach

However, Harris's comparatively lesser experience in foreign affairs, when juxtaposed with Biden's extensive background, may have implications for her administration's foreign policy approach.

During her tenure with Biden, Harris's influence on foreign policy has been relatively limited. She has consistently supported and aligned with Biden's established foreign policy positions.

Before entering the political arena as California's junior US senator in 2017, her career was primarily focused on law enforcement, serving as the district attorney of San Francisco and the attorney general of California.

Cha Du-hyeogn, director of the Center for Foreign Policy and National Security at the Asan Institute for Policy Studies in Seoul, predicted that Harris and her team might "seek to adhere more strictly to the principles and framework of the NPT" during discussions on US extended deterrence with South Korean partners.

The NPT stands for the Treaty on the Non-Proliferation of Nuclear Weapons.

As Harris has not yet articulated her own distinct foreign and security policies, she is expected to follow the overall direction established by Biden while aligning with the broader Democratic Party's stance.

"The Democratic Party places a stronger emphasis on non-proliferation principles than Biden's individual approach," Cha told The Korea Herald.

"While Biden has shown some flexibility in decisions affecting global nuclear deployment, Harris is expected to adhere more faithfully to the party's non-proliferation principles."

This suggests that Harris and her team would be less accommodating of nuclear policy discussions, which have been resonating within South Korean society. Instead, they would likely emphasize South Korea's commitment to its obligations under the NPT, as outlined in the Washington Declaration.

Cha also explained that Harris's more progressive stance on domestic issues, such as gender equality, compared to Biden, might extend to her foreign and security policies.

Progressive policies often emphasize stringent regulatory frameworks.

"As a result, Harris's approach will likely be more rigid and principle-based, ensuring that policies remain firmly within the boundaries of the non-proliferation treaty," Cha said.

Vocal on rules-based order

Harris was vocal about North Korea's illicit nuclear and missile programs that violate UN Security Council resolutions and its human rights abuses during her visit to the demilitarized zone separating the two Koreas in September 2022.

Harris publicly labeled North Korea as a "brutal dictatorship," denouncing its "rampant human rights violations, and an unlawful weapons program that threatens peace and stability."

Harris also eloquently championed the significance of the Biden administration's commitment to the international rules-based order on the global stage, including at the Munich Security Conference and the East Asia Summit in Jakarta in 2023, highlighting its crucial role in maintaining peace and prosperity in the Indo-Pacific.

In 2022, aboard the USS Howard at Yokosuka Naval Base, she accused China of "undermining key elements of the international rules-based order" and criticized its "disturbing behavior" in the East and South China Seas and "provocations across the Taiwan Strait."

Similarly, as a senator, Harris also worked on legislation promoting human rights in Hong Kong and Myanmar as well as addressing the Chinese government's abuses in the Xinjiang Uyghur Autonomous Region.

Nonetheless, Cho assessed that shifts away from established foreign policies are inevitable in the current presidential race, with less than four months remaining until the election.

"As the Democratic Party immerses itself in the election process and Biden passes the torch to the next Democratic presidential candidate, it is inevitable that not only foreign policy but all policies will lose momentum. This decline is unavoidable. In this broader context, it is reasonable to expect that policies will weaken," Cho said.

"Even if Biden had not withdrawn, the high likelihood of Trump returning means that Biden's policies would already be losing momentum."