S. Korea faces mounting defense pressure ahead of Lee-Trump summit

South Korean and U.S. national flags are displayed side by side during a rotation ceremony at Camp Casey in Dongducheon, Gyeonggi Province, June 18. Yonhap

As preparations are underway for a summit between President Lee Jae Myung and U.S. President Donald Trump, Seoul is facing increasing pressure from Washington on security issues.

The upcoming summit — the first face-to-face meeting between the two leaders — is expected to become a key diplomatic challenge for the Lee administration as it grapples to meet the Trump administration's costly demands for maintaining the alliance, including calls to take on a bigger role in countering China.

A senior Pentagon official recently praised South Korea as a "role model" for its increased defense spending and willingness to lead efforts against threats from North Korea.

Elbridge Colby, undersecretary of defense for policy, made the remarks on July 31 in a social media post following a phone call between South Korean Defense Minister Ahn Gyu-back and U.S. Defense Secretary Pete Hegseth.

"South Korea continues to be a role model in its willingness to take more of the lead in a strong defense against the DPRK and in its spending on defense," Colby wrote on X, formerly Twitter.

DPRK stands for the Democratic People's Republic of Korea, North Korea's official name.

Colby also said the two allies are "closely aligned on the need to modernize the alliance" in response to shifting regional security dynamics.

Widely regarded as a key architect of Trump's "America First" strategy in the security domain, Colby has led efforts to push U.S. allies to increase their defense budgets and assume a greater role in collective defense.

According to a recent Financial Times report, Colby pressed Japanese and Australian defense officials to clarify their potential roles in the event of a U.S.-China conflict over Taiwan.

Observers in Seoul expect similar demands to surface during the upcoming Lee-Trump summit, under the increasingly cited framework of "alliance modernization."

U.S. Defense Secretary Pete Hegseth, left, and Defense Undersecretary Elbridge Colby, meet with Philippine President Ferdinand Marcos Jr. at the Pentagon in Washington, July 21 (local time). Reuters-Yonhap

"In simple terms, alliance modernization means expanding the South Korea-U.S. mutual defense treaty beyond the Korean Peninsula and into the Indo-Pacific region, which would entail greater strategic flexibility for U.S. Forces Korea (USFK), including roles aimed at countering China," said Doo Jin-ho, a senior researcher at the Korea Research Institute for National Strategy.

"Readjusting USFK's role may not require Korea's official consent, which leaves Seoul little room for negotiation on that front."

Seoul officials are reportedly asserting that discussions over USFK's strategic flexibility were settled under a 2006 agreement. That deal acknowledged Washington’s need for operational flexibility while affirming Seoul’s stance that it would not participate in regional conflicts in Northeast Asia without the consent of the Korean public.

Diplomatic sources suggest that while a broad agreement on alliance modernization may be reached at the upcoming summit, further discussions are likely to be handled through a "two-plus-two" format involving the foreign and defense ministers of both countries.

"I don’t think we'll see concrete issues like the readjustment of USFK roles in the joint statement following the summit," Doo said. "But it wouldn’t be a surprise if Trump makes off-script remarks suggesting that Korea, as a rich nation, should pay more for its own defense."

President Lee Jae Myung attends a meeting with heads of local governments at the presidential office in Seoul, Friday. Yonhap

Meanwhile, the exact date of the summit remains unclear.

On July 31, Trump announced via Truth Social that he would host the South Korean leader at the White House "in two weeks," following the signing of a trade deal. However, that timeline — which would place the summit before Aug. 14 — appears increasingly unlikely given several upcoming events in Seoul.

The president is currently on summer vacation through Friday, according to his office.

Early next week, a foreign head of state is scheduled to visit Seoul, marking the first such visit under Lee's presidency. The government is also preparing for an official inauguration ceremony for the president on the Aug. 15 National Liberation Day holiday.

In addition, the annual Korea-U.S. Ulchi Freedom Shield joint military exercise is expected to begin in the week of Aug. 18, during which Lee will likely limit overseas travel.

Taken together, these factors point to the final week of August as the most likely window for the summit.

The Ministry of Foreign Affairs declined to confirm specific dates for the summit, saying only that the schedule will be announced jointly with the U.S. government.