Click on the banner above to explore the Tiger Project.

A debate on the future of US Forces Korea (USFK) is underway, and it is at risk of becoming a political brawl rather than a strategic analysis. Media speculation, fueled by proposed USFK cuts in a wide-ranging report from two prominent US researchers, has amplified expectations that the Trump administration will cut USFK personnel. The Senate’s draft version of the 2026 National Defense Authorization Act seems designed to guard against a precipitous move by prohibiting funds to reduce US military personnel stationed in or deployed to South Korea below 28,500 (absent certification from military and executive branch leaders that reductions are in the national security interests of the United States and undertaken after allied consultations).

Unfortunately, this figure is in some ways a legacy of encrusted layers of decisions made under changing circumstances since the armistice of 1953. US forces in Korea now reflect what remained after a series of unilateral withdrawals and redeployments that became permanent removals, leading to President George W. Bush’s 2008 pledge to maintain 28,500 troops, rather than a clear design. No military officer or civilian analyst I have encountered would claim that a “clean slate” analysis would result in what we have now. 

Dual deterrence

It’s not 2008 anymore, and any reassessment of USFK must start by accounting for the dramatic changes since the 28,500 troop number was pledged. Though the threat on the Korean Peninsula and in the region has grown considerably, so has South Korea’s ability to defend itself from absorption by the North. Deterring a conventional North Korean invasion to conquer South Korea—something USFK commanders have long been testifying as beyond the North’s capabilities—should not be the basis for USFK’s future. However, as the threat from North Korea has evolved—particularly with Pyongyang increasing its nuclear and asymmetric non-nuclear capabilities—deterrence has been crumbling, particularly of “gray zone” aggression and of limited nuclear attacks in the event of war. With an increasingly aggressive and powerful China as the “pacing threat” for Pentagon planning, simultaneous threats from China and North Korea—including nuclear escalation—should now define the baseline for USFK posture analysis. 

As numerous analyses, wargames, and tabletop exercises have demonstrated, we should discard questionable assumptions like Korea as a force posture “black hole” and other artificial barriers to and biases against considering the Korea aspect of a US-China conflict and vice-versa. With these blinders removed, the potential for a restructured US Forces Korea to help deter China—not just North Korea—becomes more clear. Though the specifics are debatable, a list like the one below would account for the requirements USFK needs for “dual deterrence”—to help deter and defeat both nuclear and non-nuclear threats from North Korea and China simultaneously or sequentially.

• Nuclear deterrent, including theater-level nuclear-capable systems
• The ability to conduct rapid non-nuclear strikes against important targets throughout North Korea, against key Chinese military facilities, and against Russian Far East military facilities
• Active and passive defenses against missiles and manned or unmanned aircraft
• Sufficient ground forces to provide protection and security for US personnel, including support for a potential noncombatant evacuation (NEO)
• Intelligence collection, analysis, and targeting capability
• Medical, logistical, and maintenance support sufficient to support high-intensity combat
• Capabilities and bases sufficient to pose a dilemma to China’s calculus for war with the United States—for example, either accept that South Korea will serve as a “sanctuary” for key US military support functions and for platforms that can hold Beijing at risk, or expend an unacceptable number of missiles and aircraft to neutralize these capabilities, while also likely drawing South Korea into the war

To meet these requirements, USFK could be restructured to be more capable and efficient, with a focus on three key aspects below: modernized airpower, advanced land-based missiles, and a more resilient, protected foundation.

Cutting-edge airpower

USFK’s airpower should be modernized and streamlined. The bulk of USFK’s combat power today is the US Seventh Air Force, whose commander is also USFK’s deputy commander. Though it is being reinforced with more fighters—and experimenting with larger “super squadrons”—it is qualitatively being left behind. US Forces Japan’s Fifth Air Force is being equipped with new F-35 fighters, while older F-16s are being transferred to Korea to make room. South Korea’s air force has also started flying F-35s and is acquiring more. Meanwhile, US F-35s have only been temporarily deployed to Korea for training, with reported plans for permanent stationing in the future.

F-35s are intended to replace F-16s and have an “enhanced capability to survive” in an “advanced threat environment” according to the US Air Force. Given China’s robust air defense capabilities, and rapid enhancements of North Korean air defenses that could be looming with Russian military-technical support to North Korea, it is time to rapidly transition USFK to F-35s. To address the growing challenges to nuclear deterrence, at least one squadron of these F-35As should be nuclear-certified, trained and prepared to be “dual-capable” with wartime nuclear and non-nuclear missions from multiple bases.

At the same time, Korea should be the location of choice for forward-stationing of new collaborative combat aircraft (CCAs)—unmanned aircraft that fly in concert with and are controlled by manned aircraft. A recent wargame explored the advantages of forward-stationing CCAs in the region, suggesting this could enhance effectiveness while limiting vulnerability to missile attacks due to the smaller basing “footprints” required for CCAs. If the Pentagon is looking to cut personnel numbers while enhancing capability, replacing F-16s with F-35s and CCAs could be a way.

More and better land-based missiles

As our previous analysis has recommended, USFK should have priority for new ground-based missile strike capabilities to ensure it can strike quickly at great distances. 

USFK’s ground maneuver forces have already been downsized—now just one rotational mechanized infantry brigade combat team of about 4,400 soldiers—compared to 450,000 soldiers in South Korea’s Army. Today, USFK ground forces’ punch primarily comes from its 210 Field Artillery Brigade. As part of ongoing US Army missile upgrades, the brigade’s M270 multiple launch rocket systems can be fitted with two launch pods with two four-hundred-kilometer-range Precision Strike Missiles per pod, providing deeper reach into North Korea and to China over the current three-hundred-kilometer-range Army Tactical Missile System, while doubling the missiles per launcher.

USFK should also be reconfigured to include a deployed or permanently stationed Army Multi-Domain Task Force (MDTF) armed with longer-ranged missiles, similar to the US Army Pacific’s First MDTF which deployed a new Typhon Mid-Range Capability missile battery to the Philippines this Spring. A USFK MDTF should also include the “Dark Eagle” Long Range Hypersonic Weapon—recently deployed to Australia for exercises. With a 1,725-mile range, these could hold at risk all of North Korea—as well as Beijing and every port China would use for an invasion of Taiwan. As retired US Army Colonel David Maxwell suggests, the United States could even establish a combined US-South Korea MDTF for similar capabilities with fewer US personnel and systems. 

One of the US Marine Corps’ new littoral regiments could also be deployed periodically with its anti-ship missile, anti-drone, and surveillance capabilities, perhaps on South Korea’s strategic Northwest Islands, to help deter and defend at the most likely flashpoint for a Korean conflict. It could also interdict the narrow point in the Yellow Sea between Korea and China’s Shandong Peninsula—similar to NMESIS missiles deployed to maritime chokepoints in the Philippines.

Resilient, protected foundation

USFK’s basing and logistics infrastructure is vital, not just to the US and South Korean defense of Korea, but to the entire western Pacific military posture of the United States and its allies. Camp Humphreys, home to USFK headquarters, is the largest US military base outside the continental United States, with capacity to match. USFK’s bases are home to vital enablers for military operations in the region performing important functions such as medical, intelligence, communications, maintenance, resupply, and repair. Though ways may be found to enhance efficiency to reduce the cost or personnel footprint of individual bases and supporting functions, retaining these bases and these support capabilities is vital to strong deterrence and defense in the western Pacific.

These assets are well-positioned to be “close to the fight” without being on the front lines. Deterrence is their first line of defense. In the event of a war with the United States, China would face the dilemma of either having to accept de facto sanctuary for these US military supporting functions on their doorstep, or attacking them and dragging South Korea into the war. Meanwhile, North Korea likely expects it cannot launch major attacks these bases without bringing on a full-scale US military response that could end its regime. 

However, as Chinese and North Korean strike capabilities improve, the passive and active defenses and resilience of these bases must also be improved to make them less vulnerable and to help deter attacks upon them. Improved counter-missile and counter-drone defenses, along with training and preparations for dispersed operations, for example, are vital to ensure these bases and functions do not become lucrative targets. 

Realistic analysis and transformation

With a rare window now open to consider transformational change of USFK, and to re-address the longtime artificial constraint of 28,500 troops, there is no time to waste. Whether or not all the specific ideas above are adopted—and whether or not US personnel numbers are significantly reduced—the necessary transformation of USFK should be a win-win for various priorities: improving efficiency, strengthening “dual deterrence,” and enabling more regional flexibility. Only US adversaries should be upset by the outcome of a more streamlined, less vulnerable USFK that is also more powerful, agile, and strategic—alongside a more capable South Korean military within a modernized US-South Korea alliance.

Markus Garlauskas is the director of the Indo-Pacific Security Initiative at the Scowcroft Center for Strategy and Security, leading the Council’s Tiger Project on War and Deterrence in the Indo-Pacific. He is a former senior US government official with two decades of service as an intelligence officer and strategist, including as chief strategist for US Forces Korea. He posts as @Mister_G_2 on X.

The Tiger Project, an Atlantic Council effort, develops new insights and actionable recommendations for the United States, as well as its allies and partners, to deter and counter aggression in the Indo-Pacific. Explore our collection of work, including expert commentary, multimedia content, and in-depth analysis, on strategic defense and deterrence issues in the region.

Further reading

Tue, Jun 24, 2025

The ‘ironclad’ US-South Korea alliance is outdated. A new age requires a ‘titanium’ alliance.

New Atlanticist By Markus Garlauskas

Washington and Seoul must set a new foundation for the seventy-year-old alliance that reflects the current strategic environment.

Crisis Management Defense Policy

Thu, Jul 10, 2025

South Korea is the ideal anchor for the first island chain

Issue Brief By Brian Kerg

The assumptions underpinning analysis and discussion of conflict in the Indo-Pacific are due for a rethink. Though many conversations about Chinese military aggression assume South Korea would not get involved, it could play a decisive role in deterring and defeating an attack on Taiwan.

China Conflict

Wed, Aug 27, 2025

Navigating the new normal: Strategic simultaneity, US Forces Korea flexibility, and alliance imperatives

Issue Brief By Bee Yun Jo

The future of deterrence on the Korean Peninsula—and indeed, the wider Indo-Pacific region—will hinge on Seoul’s ability to reframe US force realignments not as unilateral disengagements but as catalysts for action.

Defense Policy Korea

Image: US Army Soldiers and Republic of Korea army soldiers participate in a 12-mile ruck march as they work to earn an Expert Infantry, Soldier, or Field Medical Badge on Camp Humphreys, South Korea, April 25, 2025. (US Army photo by Pfc. Wilfred Salters Jr., 2nd Infantry Division/ROK-US Combined Division public affairs)