U.S. President Donald Trump attends the draw for the 2026 FIFA World Cup at the Kennedy Center in Washington on Dec. 5, 2025, in this photo released by Reuters. (Pool photo)
SEOUL, Dec. 6 (Korea Bizwire) — A sweeping shift in American national security priorities — from reasserting influence in the Western Hemisphere to elevating Taiwan’s defense and omitting North Korea’s denuclearization — is prompting fresh debate in Seoul over what the changes signal for South Korea’s security role in Asia.
The White House on Thursday released President Donald Trump’s new National Security Strategy (NSS), invoking enforcement of a “Trump corollary” to the Monroe Doctrine while urging Seoul and Tokyo to build capabilities to help defend the First Island Chain — a key geographic buffer against China — without once mentioning North Korea’s nuclear program.
The 33-page report arrives as Seoul and Washington pursue what they call alliance “modernization,” a vision that expects South Korea to shoulder more responsibility for its own defense and contribute more visibly to addressing “regional” threats, including those linked to Beijing’s growing assertiveness.
The document underscores Washington’s desire for Indo-Pacific allies to safeguard maritime security amid China’s expansive claims in the South and East China Seas and its activities around Taiwan. It lands at a moment when South Korea is balancing its military alliance with the U.S. against a pragmatic effort to maintain stable ties with China — critical both for trade and efforts to influence North Korea.
“We will build a military capable of denying aggression anywhere in the First Island Chain. But the American military cannot, and should not have to, do this alone,” the NSS says, urging allies to “step up and spend — and more importantly do — much more for collective defense.”
Given Trump’s longstanding demands for greater burden-sharing, the strategy calls explicitly on Seoul and Tokyo to boost defense spending and develop new capabilities to deter adversaries and protect the island chain.
Donald Trump, the president of the United States, and Xi Jinping, the president of China, walk and talk as they leave the meeting room after concluding the U.S.-China summit at the Naraemaru protocol hall at Busan’s Gimhae Air Base on Oct. 30. (Yonhap)
Analysts say the message is unmistakable: Washington expects South Korea to play a greater role beyond the Korean Peninsula, potentially including contingencies involving Taiwan. “Although China is not named, it’s clear Trump expects allies, including South Korea, to support this strategy of deterrence and denial,” said Andrew Yeo, chair in Korean studies at the Brookings Institution.
Recent bilateral language appears to support that view. A U.S.–South Korea fact sheet released this fall commits both sides to strengthening deterrence against “all regional threats,” echoing calls for South Korea to contribute to countering China. Trump’s approval for Seoul to build nuclear-powered submarines is widely interpreted as another push toward deeper allied capability.
The NSS also highlights plans to restore American dominance in the Western Hemisphere, reviving worries that a tilt toward hemispheric priorities might weaken U.S. focus on the Indo-Pacific. The report seeks to defuse those concerns, pledging to “harden and strengthen” military presence in the Western Pacific — a signal that U.S. forces in Korea are likely to remain, though future troop levels are uncertain.
More troubling for Seoul was what the NSS left out: any reference to denuclearizing North Korea. The omission raises questions about whether Washington is downgrading the Korean Peninsula on its policy agenda, especially as alliance reforms shift primary responsibility for conventional deterrence against Pyongyang to Seoul.
Some analysts caution against over-reading the silence. The NSS did not mention nuclear non-proliferation at all, said Yeo, suggesting that the administration may address North Korea in its forthcoming National Defense Strategy.
President Lee Jae-myung and U.S. President Donald Trump walk and talk as they move to the summit venue at the Gyeongju National Museum on Oct. 29. (Photo provided by the Presidential Office.)
Others see tactical calculation. Patrick Cronin, Asia-Pacific security chair at the Hudson Institute, said the omission could preserve diplomatic flexibility should Trump and Kim Jong-un hold a summit. “If I were Kim Jong-un, I would feel slighted and inclined to include some bold nuclear ambitions as part of the preparation,” he said.
But Rob Rapson, a former acting U.S. ambassador to South Korea, warned the absence may reinforce perceptions of Washington as an increasingly “unreliable” ally.
The contrast with earlier strategies is stark. The 2017 NSS emphasized “complete, verifiable and irreversible denuclearization” of the peninsula, while the Biden administration’s 2022 edition pledged continued efforts toward that goal.
As Seoul assesses the strategy, the core question remains whether Washington’s recalibration — intended to contain China — leaves South Korea facing broader security expectations abroad and less clarity at home about U.S. commitment to its most existential threat.
M. H. Lee (mhlee@koreabizwire.com)
