The Unintended Consequences of Trump’s Turn Against South Korea

By Eric S. Edelman

Friday, August 21, 2026

 

The annual joint military exercises with U.S. and South Korea are ending early after President Donald Trump lashed out on Truth Social on August 16, complaining the drills were too costly (with the U.S. bearing too much of the burden) and “totally inappropriate and hostile” to a North Korean regime that has been, as far as he is concerned, “unthreatening and respectful.”

 

Judging by the the Truth Social post and his subsequent comments in the Oval Office, Trump’s anger seems rooted the fact that the Koreans declined his request for assistance in dealing with Iran’s closure of the Strait of Hormuz (although Trump also said, confusingly, that we didn’t really need South Korea’s help), though it may simply be an effort to distract the American public from the cul de sac into which the president has driven U.S. policy in the Gulf.

 

Trump’s ire is the result not only of South Korea’s unwillingness to help him out of the war that he began without consulting Seoul (and which has created a triple whammy of inflation, higher interest rates, and a weakened currency in a country that imports 70 percent of its energy from Gulf) but also a longer-term view of U.S. alliance relationships as a protection racket in which South Korea has been unwilling to bear its share of the burden of common defense. Trump wrongly thinks the alliance solely benefits the Koreans and that the U.S. has no real interest. He also believes that South Korea, like other U.S. trading partners, has been taking advantage of America for years. He has demanded South Korean investments in the U.S. to offset our trade deficit, and some have suggested his anger stems from South Korea’s foot-dragging on a $350 billion pledge it made in 2025.

 

Trump’s account of the state of the U.S.-Korean defense relationship and burden sharing is, as CNN’s Daniel Dale has pointed out, a farrago of lies and misrepresentations. The reality is that, since 1991, South Korea has contributed to the maintenance of U.S. forces in Korea through a series of “special measures agreements” (SMAs) through which the Republic of Korea pays for labor, logistics, and construction to help defray U.S. costs. Under the current SMA, South Korea will pay $1.19 billion to help defray the costs of the U.S. military presence, but as an ally, South Korea also consumes U.S. defense goods and services. In 2025, the Koreans had $30 billion worth of active cases under the Foreign Military Sales (FMS) program, including items like the F-35, the Global Hawk UAV, Patriot missile defense systems, and the AEGIS air and missile defense system. The South Koreans also procure roughly $1.5 billion worth of defense goods a year through direct commercial sales.

 

Of course, the U.S. benefits from its very much diminished presence in South Korea (now down to slightly under 30,000 troops, compared with twice that number during the height of the Cold War), because it helps maintain stability and security in northeast Asia, a crucial region abutting North Korea, China, and Russia. Those nations’ tightening collaboration, along with their ties to Iran, was highlighted by the 2024 National Defense Strategy Commission that I co-chaired and which noted that “this new alignment of nations opposed to the U.S. interests creates a real risk, if not likelihood, that conflict anywhere could become a multitheater global war.” In other words, North Korea is not just a threat to a part of the world that is crucial for American prosperity because of its importance for semiconductor and electronic manufacturing—it  represents a broader challenge to U.S. global interests. It is from that point of view that the president’s pronouncement seems particularly ill-timed.

 

Contrary to the president’s assertion that North Korea is “unthreatening,” his own director of national intelligence’s annual threat assessment for 2026 concluded that North Korea’s “WMD, conventional military capabilities, illicit cyber activities, and demonstrated willingness to use asymmetric capabilities to attack South Korea and the U.S. pose significant threats to the U.S. and its allies.” The Financial Times reports that North Korea is spending 15.8 percent of its GDP on defense, “supporting an arsenal of increasing diversity and sophistication that includes short-range tactical nuclear weapons, land-attack cruise missiles and a growing fleet of road-mobile ballistic missiles as well as intercontinental ballistic missiles (ICBMs) such as the solid fuel Hwasong-18.” The DNI assessment also points out that “the benefits that North Korea receives for its support for Russia in the war against Ukraine have increased North Korean capabilities. North Korean military forces have gained valuable combat experience in 21st Century warfare along with equipment.” As former State Department official Frank Rose has pointed out, this is an argument for more joint exercises—not fewer.

 

Moreover, the North Koreans, in the days leading up to Trump’s post, had launched two ballistic missile “tests” to demonstrate their displeasure with the upcoming exercises. The North Koreans have also, according to Ukrainian intelligence, agreed to deploy 50,000 troops (they had earlier deployed some 11,000) to Russia to help overcome Russia’s manpower mobilization issues and assist in the war in Ukraine. This allegedly includes a ballistic missile battalion—and indeed there have already been reports of a North Korean-manufactured missile fired at Ukraine. In the wake of the president’s intervention in the South Korea exercises, North Korea fired off 10 medium-range ballistic missiles, and Kim Jong Un’s sister declared that the U.S. curtailment of the joint exercises changed nothing in the bilateral relationship with the U.S. In that context, the president’s directive looks less like an example of the Reaganesque “peace through strength” that he and his secretary of defense are fond of touting and more like an act of rank appeasement.

 

The president’s post also coincided with the news that the USS George Washington, the only U.S. aircraft carrier in the Indo-Pacific region, was being redeployed to the Middle East to relieve the lengthy deployment of the troubled USS Abraham Lincoln, which has been at sea for more than 270 days and which has reportedly been plagued with deteriorating morale among its crewmembers. These factors have called into question Washington’s credibility as a security guarantor not just for South Korea but for the East Asian region as a whole.

 

The episode clearly has unnerved the South Koreans and led President Lee Jae Myung to call for “for faster progress towards acquiring nuclear powered submarines and transferring wartime operation control of South Korean forces, which he has pledged to achieve by 2030.” The expressions of concern rippled beyond the Korean Peninsula and “deepened concerns about U.S. reliability among Indo-Pacific allies who were already nervous” about Trump’s rhetoric on Taiwan. As to Michael Green, a senior director for East Asia in the George W. Bush administration, told FT,  “one U.S. ally likened working with the Trump administration to ‘going into space with Sigourney Weaver’ in the movie Alien. ‘The latest monster to spring from the ceiling was the president’s threat to cancel US military exercises with South Korea,’ said Green.” The Trump administration’s recent moves are inevitably being viewed through the lens of the upcoming visit by President Xi Jinping to Washington, and they are guaranteed to heighten the anxieties of U.S. allies in the region that any agreements reached at that superpower summit are likely to come at their expense.

 

The immediate impact of Trump’s ill-considered social media post is to force our Asian allies to consider additional measures of security self-help in the face of what appears to be the U.S.’s waning commitment to the region’s security (despite what many anticipated would be a reprioritization of East Asian security in a second Trump administration). Where this will ultimately end up is impossible to know, but the ultimate self-help step would be for South Korea, Japan, and potentially Taiwan to pursue their own independent nuclear deterrents. The debate in South Korea has been ongoing for some time, and the clamor for an independent nuclear deterrent will now undoubtedly increase. Japan seems on the surface like a less likely candidate for nuclear proliferation for obvious reasons—it was, after all, the only country to sustain bombardment by atomic weapons. But Japan’s national security has been so closely tied to the U.S. for so many years that if it is forced to look for a Plan B independent of a reliable U.S. security guarantee, nuclear weapons are likely to look a lot more enticing. The prospect of “friendly proliferation” was almost inevitable in the wake of the administration’s failure to prioritize extended nuclear deterrence in its National Defense Strategy. It will now receive an added fillip from the president’s impulsive expression of anger at South Korea. It is another major blow against the teetering nuclear non-proliferation regime and, in the wake of the ill-considered Saudi nuclear deal, betrays a cavalier disregard of the last remaining vestige of the arms control era and global nuclear security more broadly.