It’s not widely known that South Korea is the world’s fifth ranked military power—more powerful than even Japan, Germany, France, or the UK. By contrast, its foe, North Korea, is ranked thirty-first. Trump is lashing out at South Korea, not because it free-rides on the Pentagon (it doesn’t), but because the Lee administration doesn’t want to become embroiled in Trump’s wars, either against Iran or China.
21 August 2026
By Stephen Gowans
Irritated that South Korea had declined to send warships to the Persian Gulf to help the United States open the Strait of Hormuz, US president Donald Trump lashed out at Seoul, accusing the US ally of free-riding on the United States. The US “can’t go around and protect all of these countries, especially when they’re not there to help us,” complained Trump. “I said, ‘Wait a minute. We have 39,000 soldiers over there, guarding you from Kim Jong-un, your next-door neighbor, and you’re not going to help us on a very easy military operation in Iran?’” [1]
The United States has 28,500 soldiers in South Korea, not 39,000. And opening the Strait of Hormuz is the antithesis of an easy military operation. But lay Trump’s arithmetical lapse and military ineptitude aside. Does the United States have to guard South Korea from Kim Jong Un because the country is incapable of defending itself, as Trump alleges? The answer turns out to be fairly obvious and non-controversial. No, it does not. “South Korea could almost certainly defeat a North Korean invasion on its own.” [2] That’s the view of Elbridge Colby, the US undersecretary of defense for policy. So, if Trump thinks the Pentagon has to guard South Korea from Kim Jong Un, he must have slept through meetings with Pentagon staff.
In his 2021 book The Strategy of Denial: American Defense in an Age of Great Power Conflict, Colby wrote that “South Korea can … defend itself from a North Korean invasion on its own or with modest US support.” He pointed out that in terms of military expenditures, South Korea spends “more than twenty-five times what North Korea spends” and that “the South Korean military also benefits from an advanced economy and access to US equipment and expertise.” In contrast, North Korea’s conventional military “is antiquated, even decrepit.” South Korea could, Colby concluded, “almost certainly defeat a North Korean invasion on its own.” [3]
This too is the view of South Korea’s defense minister Ahn Gyu-back. In May he said that “we wouldn’t have much trouble defending ourselves.” The country’s president Lee Jae Myung was more emphatic. “Actually, we wouldn’t have any trouble at all.” [4]
Colby’s, Ahn’s, and Lee’s assessments are backed by the numbers. South Korea’s population is twice as large as North Korea’s. Its GDP is 58 times larger. Seoul’s military budget alone is bigger than all of North Korea’s economy—40 percent larger. Its military expenditures are at least over five times as large as Pyongyang’s military outlays (25 times larger according to Colby). South Korea has 4.1 million soldiers (600,000 active-duty troops and 3.5 million reserves), more than twice as many as North Korea, which has 1.9 million soldiers (1.3 million active-duty troops and 600,000 reserves.)
Of US allies, South Korea is the most powerful militarily—more so than even Japan, Germany, France, and the UK. South Korea’s military is ranked fifth in the world, behind only the United States, China, Russia, and India. North Korea, in contrast, ranks thirty-first, weaker even than tiny Greece. [5]
Currently, South Korean troops make up 99 percent of combined US-South Korean forces in South Korea, 95 percent of the naval forces, and 90 percent of the air forces. [6] In a war with North Korea, almost all of the fighting would be done by South Koreans. Americans would play a peripheral role.
Far from being a security burden, the world’s fifth ranked military power is a formidable US military asset, one Washington would like to use to check its top rival, China. The People’s Republic, according to the leading US military official in Korea, General Xavier Brunson, could “deny American access to vital global markets,” the rationale for dubbing Zhongguo America’s top security threat. [7] The “China problem” in the US view, is not that the country poses a military threat to the US homeland (it doesn’t) but that it could squeeze corporate America and wealthy US investors out of lucrative markets in East Asia.
Brunson heads three military commands.
- US Forces Korea (USFK), the contingent of 28,500 US troops stationed on the Korean peninsula.
- The United Nations Command, established by the UN Security Council in 1950 to evict North Korean forces from South Korea. While active hostilities ended on 27 July 1953 with an armistice, the belligerents have never signed a peace treaty and remain technically at war. For this reason, the UN Command continues. Its current mission is to manage the armistice.
- The Combined Forces Command. “Combined forces” refers to the South Korean military and USFK together. It is worth repeating that the combined forces are 95 percent South Korean. In peacetime, South Korea’s military is under the control of the the country’s top general. In wartime, it falls under Brunson’s command.
The mission of the UN Command is straightforward: to deter North Korean aggression and “uphold peace and security on the Korean peninsula.” But the missions of the two other commands are broader. Like the UN Command, both aim to defend and protect South Korea. But they are also pledged to “maintain stability in Northeast Asia,” according to the USFK website. As the Pentagon understands it, Brunson’s mission extends beyond the Korean peninsula to all of Northeast Asia. That means that US forces could use South Korea as a base of operations against both China and Russia. It also means that the world’s fifth ranked military power could be pressed into service under Brunson’s command to wage war against either or both of these US rivals. Needless to say, these interpretations raise serious concerns among some, though not all, South Koreans. Conservatives generally favor submitting to US leadership, even if it means becoming entangled in wars with China or Russia. Progressives, in contrast, worry about Washington embroiling them in a military contest with a great power.
Brunson has done little to allay South Koreans’ concerns about the United States enmeshing them in a war that would inevitably have devastating consequences for their lives. South Koreans are not unaware of the fate of the United States’s Persian Gulf allies in the Iran War, countries which, like South Korea, host US military bases in the neighborhood of a US enemy. Brunson has referred to the Korean Peninsula as “a key strategic terrain vital to … advancing American interests in the region.” [8] When one considers that the key American interest in the region is checking China, and more specifically, preventing it from asserting sovereignty over Taiwan, then South Koreans can be understandably apprehensive about the role the Pentagon foresees them playing in pursuit of US objectives.
A year ago, Brunson told an audience, “If you were to draw a triangle from Tokyo to Seoul to Manila, about 52% of global trade comes through that area. And I think there’s a recognition that we all ought to have that if something happens in the region, there’s going to be a call for nations to react accordingly.” [9] The South Korean newspaper, The Hankyoreh, reported that Brunson was “advocating for building the capacity for the US and [South] Korea to respond to common enemies,” the most important of which, in the US view, is China. [10] Brunson has “repeatedly defined [South] Korea as a military hub for the US containment of China” and believes “that [South] Korea, the US and Japan should join forces to hem in China.” [11]
Washington is modernizing its alliance with South Korea, as part of the Trump Administration’s 2025 National Security Strategy. The strategy seeks to prevent China, Russia, and Iran from becoming hegemons in their respective regions. If any of these powers become regionally dominant, they will, in the strategy’s assessment, be in a position to deny US investors and business-owners access to their regional markets. US strategy and war-planning documents almost invariably cite the need to safeguard US access to foreign markets as a key security aim. The Pentagon and US foreign policy establishment plan wars around the pursuit of business and investor interests.
The plan goes on to assess that the United States does not have the resources to fight more than one potential hegemon at any one time. It must therefore prioritize its efforts and focus on the largest region and most significant potential hegemon: China.
If China is not contained, the plan’s authors write, it will use force to dominate its neighbors, beginning with Taiwan, and achieve regional supremacy. If it achieves regional supremacy, it will be in a position to deny US businesses and investors access to Asian markets.
In order to prioritize China, the strategy calls on the United States to:
- Offload responsibility for preventing Russia from seeking hegemonic status in Europe to its NATO allies;
- Transfer resources for defending Ukraine to defending Taiwan;
- Contain Iran by arming Israel;
- Modernize its alliance with South Korea. [12]
Modernizing the US-South Korea alliance means shifting command of the officially ongoing war with North Korea from Washington to Seoul. This will free up US resources to concentrate on preventing China from seizing control of Taiwan, and ensure that if China and North Korea initiate concurrent military actions—China against Taiwan and North Korea on the peninsula—that US forces can remain focused on China, while South Korea holds down the Korean front. As we have seen, Washington recognizes that the world’s fifth ranked military power can easily take on the thirty-first. But for South Korea to assume its new responsibility, authority to command its own forces in wartime must pass from Brunson and the Combined Force Command, where it currently sits, to a South Korean general. The process of carrying out this transition is called OPCON (operational control) transfer.
South Korea regained peacetime OPCON in 1994, and Washington has promised at various times to transfer wartime OPCON. Its promises, however, have always proved empty. South Korean progressives have been in favor of regaining sovereignty over the country’s armed forces and most conservatives, being strongly inclined to philodespotia (love of their imperial masters) have opposed it. South Korea’s Ministry of Defense has been pushing for the transfer to take place next year but Brunson favors delaying until 2029. [13]
Along with OPCON transfer, Washington has also been pursuing the idea of strategic flexibility: the notion that US forces in Korea should be deployed to missions throughout Northeast Asia, rather than being limited to action on the Korean peninsula. “Colby thinks that USFK’s primary role shouldn’t concern North Korea but China, and has consistently referred to the possibility of either withdrawing or redeploying US troops in Korea.” [14] In Brunson’s words, having the USFK “moored in place is not militarily expedient.” [15] If strategic flexibility means the exit of US forces from South Korea, this would be a boon for all Koreans, even if the exit would be vigorously opposed by conservatives. US forces remaining on the peninsula is quite a different matter. If Washington intends to use South Korea as a platform from which to attack China or Russia, South Koreans will end up as pawns sacrificed in a great power game of international chess.
The Lee Jae Myung administration “has drawn a line in the sand, holding to the position that the potential for USFK to intervene in the event of a conflict over Taiwan is not up for discussion.” [16] This may be one of the top reasons Trump has lashed out at Seoul. Recently, the Pentagon sent a questionnaire to NATO members, outlining what Trump expects from US subordinates: Support for US foreign policy; access to their military bases; and purchases of US weapons. [17] Lee’s clear opposition to the Pentagon using South Korea as a platform from which to attack US rivals has very likely agitated Trump. Chiding Seoul for failing to assist the United States in the Iran War debacle, and falsely accusing South Koreans of free-riding on the Pentagon, reflects his frustration over the refusal of Seoul to sacrifice South Koreans for US, and Trump’s own, self-serving interests. In short, Seoul is balking at the possibility of South Koreans being used as cannon fodder in a US war against China whose aim is to prevent wealthy US investors and business owners from possibly losing access to lucrative Asian markets.
Stephen Gowans is the author of Patriots, Traitors, and Empires: The Story of Korea’s Fight for Freedom.
1. “Korea latest casualty of Trump’s misplaced frustration over mess in Iran, says US media outlet,” The Hankyoreh, 2026-08-19.
2. Elbridge A. Colby, The Strategy of Denial: American Defense in an Age of Great Power Conflict, Yale University Press, 2021, p. 263.
3. Colby, p. 263.
4. “Lee calls sovereign defense ‘fundamental’ amid rift with US over OPCON transfer timing,” The Hankyoreh, 2026-05-27.
5. 2026 Military Strength Rating, Global Firepower,https://www.globalfirepower.com/countries-listing.php; “N. Korea ranks 34th in global firepower ranking; S. Korea 5th,” The Korea Times, Jan 14, 2025; “Kim Jong Un Wants a Military That’s More Than Just Nukes—and Russia Can Help,” The Wall Street Journal, Sept. 23, 2025; “USFK commander sets early 2029 as target date for OPCON transfer,” The Hankyoreh, 2026-04-24; “Lee says Korea must be able to defend itself without foreign troops, states resolve to reclaim OPCON by 2028,” The Hankyoreh, 2026-04-29.
6. “Korea is more than ready to regain OPCON. Is the US ready to relinquish it?” The Hankyoreh, 2026-06-24.
7. Statement of General Xavier T. Brunson, before the 119th Congress Senate Armed Services Committee, April 22, 2026.
8. Ibid.
9. “USFK commander hints at changes to US troop presence in Korea,” The Hankyoreh, 2025-08-11.
10. Ibid.
11. “Why does the USFK commander keep butting heads with Seoul?” The Hankyoreh, 2026-06-29.
12. National Security Strategy of the United States of America, November, 2025, https://www.whitehouse.gov/wp-content/uploads/2025/12/2025-National-Security-Strategy.pdf
13. “Lee calls sovereign defense ‘fundamental’ amid rift with US over OPCON transfer timing,” The Hankyoreh, 2026-05-27.
14. “Korea mulls how to respond if US demands ‘strategic flexibility’ of USFK at summit,” The Hankyoreh, 2025-08-20.
15. “USFK commander stresses changing geopolitical environment in pitch to ‘modernize’ alliance,” The Hankyoreh, 2025-08-11.
16. “Korea mulls how to respond if US demands ‘strategic flexibility’ of USFK at summit,” The Hankyoreh, 2025-08-20.
17. “Korea latest casualty of Trump’s misplaced frustration over mess in Iran, says US media outlet,” The Hankyoreh, 2026-08-19.




