The May-August 2023 reporting period saw further divergence between Washington’s relations with Seoul and Pyongyang. This dynamic was an acceleration of a trend already evinced at the April Joe Biden-Yoon Suk-yeol summit that produced the Washington Declaration modernizing US-South Korea extended deterrence, and the alliance as a whole. Washington-Seoul bonhomie contrasts manifestly with Washington-Pyongyang relations, whose level of hostility remains the same as four months ago, 14 months ago, or 24 months ago. That is, all the positive action during summer 2023 came from the continued dramatic growth in the US-South Korea alliance, notably via the extraordinary formation of a genuine trilateral US-South Korea-Japan quasi-alliance. This development has been in the works for the last 18-24 months, was given momentum by improving South Korea-Japan government relations and a Yoon-Kishida summit in May, and was concretely founded in August at the US-South Korea-Japan summit at Camp David.

All this was in addition to sideline meetings (bilateral and trilateral) among Biden, Yoon, and Kishida at the May G7 and the July 2023 NATO summit. Thus, the period between May and August 2023 in US-South Korea relations unfolded as a sequence of formative diplomatic events, accompanied by continued Washington-Seoul practical cooperation (e.g., combined military exercises, including some with Japan), culminating in the 2023 US-South Korea-Japan Camp David summit. The summit’s deliverables—especially the institutionalization of trilateral military exercises and the Commitment to Consult agreement obliging Washington, Seoul, and Tokyo to immediately consult each other in the case of regional threats or contingencies—meet some scholarly definitions of an alliance. Perhaps that is a bridge to far—there is no trilateral mutual defense treaty—and certainly there is no East Asian NATO in nuce. But the progress in US-South Korea-Japan relations is a major foreign and security policy shift, even if questions remain about its long-term sustainability in the face of potential domestic political changes.

Figure 1 US president Joe Biden remarks on North Korean leader Kim Jong-Un’s nuclear tests, while visiting South Korea president Yoon Suk Yeol in Seoul. May 21, 2022. Photo: Reuters/Jeon Heon-Kyun

In the background of this deterrence- and containment-focused trilateral tie-up are China and North Korea, both of which have criticized increasing US-South Korea-Japan security cooperation. Given this antagonistic context, it is unsurprising that Washington-Pyongyang relations did not improve over the May-August 2023 period. To the contrary, in fact. The Kim Jong Un regime instead exacerbated a growing Korean Peninsula and Northeast Asia arms race with multiple ballistic missile tests and demonstrations, including both the (second) successful launch of the Hwasong-18 solid-fuel intercontinental ballistic missile (ICBM) in July and failed military satellite launches in May and August. A July military parade—celebrating 70 years since the signing of the Korean War armistice—featured ICBMs (both Hwasong-17 and Hwasong-18 models), drones, (UAVs), and other high-tech weaponry in violation of UN Security Council sanctions. The presence of Chinese and Russian delegations at the parade indicated both that North Korea was re-opening post-COVID (a re-opening made official in August) and that the Kim regime is potentially interested in ramping up armaments sales to Russia, which, according to US intelligence, are continuing to take place and likely will further support Russia in its war against Ukraine, which is backed by the US. The New York Times reported (in early September) that the US government believes Kim Jong Un is scheduled to travel to Vladivostok to meet Russian President Vladimir Putin to make final progress on a Pyongyang-Moscow arms deal.

US-South Korea-(Japan!) Relations: Three’s Company

An already full 2023 in US-South Korea diplomatic relations continued in May with the G7 summit in Hiroshima, to which South Korea was invited as an observer. There was no significant Biden-Yoon sideline bilateral, as the G7 came on the heels of a Biden-Yoon summit during Yoon’s pomp-and-circumstance state visit to fête the 70^th anniversary of the US-South Korea alliance. However, Biden used the sidelines of the G7 to hold a short trilateral meeting with Yoon and Japanese Prime Minister Kishida Fumio. This meeting was the opportunity for Biden to invite his counterparts to come to the US for a trilateral summit in late summer, which became the historic Camp David summit in August.

A tripartite summit at Camp David is historic in and of itself. It was the first standalone US-South Korea-Japan leader-level summit, the prospect of which for decades seemed highly unlikely due to historical animosity and domestic politics in Seoul and Tokyo. Precisely this rocky background animated a significant part of the summit desiderata—namely, the institutionalization of cooperative mechanisms agreed upon in the Spirit of Camp David joint statement. Biden, Yoon, and Kishida each seemingly realized that a superficial statement of principles and political agreement to cooperate—as denoted in the gauzier Camp David Principles statement—would be vulnerable to both adverse domestic political conditions (e.g., future presidents with less belief in alliances) and challenges from international actors (e.g., wedge strategies by China or North Korea). Consequently, a major component of the Camp David outcome was the establishment of annual trilateral leader-level meetings; annual trilateral meetings of foreign ministers, defense ministers, national security advisors, and commerce and industry ministers; an annual trilateral Indo-Pacific Dialogue at vice-minister level; and multi-year trilateral military exercises.

Figure 2 South Korean President Yoon Suk Yeol, left, speaks during a joint news conference with President Joe Biden, center, and Japan’s Prime Minister Kishida Fumio on Friday, Aug. 18, 2023, at Camp David, the presidential retreat, near Thurmont, MD. (AP Photo/Andrew Harnik)

No practice of international affairs is irrevocable, but the rhetorical investment and practical/planning commitment to realizing these projects in the mid-term future means that future leaders in Washington, Seoul, and Tokyo will have a harder time abrogating participation in this trilateral quasi-alliance, just as adversary states will have a harder time breaking apart cooperation externally.

These institutionalized meetings were accompanied by pledges—peppered throughout the Spirit of Camp David—to cooperate in a range of areas: security/defense, Indo-Pacific regionalism, economy and technology, and public health.

Aside from the aforementioned multi-year trilateral military exercises, the security/defense dimension of the Spirit of Camp David statement covers ballistic missile defense cooperation, a working group on North Korean cyber activities, enhanced information sharing (improving TISA (Trilateral Information Sharing Agreement) and GSOMIA (General Security of Military Information Agreement) utilization), and discussion on countering disinformation campaigns. Taken together, the US-South Korea-Japan security/defense cooperation outlined at Camp David is an ambitious project aiming at enhancing deterrence against both North Korea and China. Both states responded (as expected) with ire, and although Beijing was more muted in its rhetoric than Pyongyang, Xi Jinping cannot help but notice that Camp David’s security/defense areas touch on the Three Nos that China extracted from South Korea as a partial resolution to the diplomatic dispute over the installation of a US THAAD battery on South Korean territory in 2017.  (The three noes are: No more THAAD batteries in South Korea, No integrated US-South Korea ballistic missile defense system, No trilateral alliance with Japan). Raising the stakes even higher was the fact that South Korea signed on to the Spirit of Camp David statement including its direct reference to the collective need to defend the rules-based international order in and around the Taiwan Strait, which China clearly considers a red line.

The economic and technology counterpart to Camp David’s security/defense component both anchors the US-South Korea-Japan “minilateral” in multilateral frameworks, and dovetails with much of the trade/technology de-risking/de-coupling vis-à-vis China that the US has emphasized over the last six years. On the multilateral side of the equation, trilateral effort to protect the rules-based international economic order gets its obligatory shout-out, as does both APEC and Indo-Pacific Economic Framework (IPEF) more regionally. The US, South Korea, and Japan also pledged to work together to improve uptake into international economic institutions of (still to be determined) standards for emerging technologies (e.g., artificial intelligence). On the de-risking/de-coupling side, future trilateral Economic Security Dialogues promise to support the Minerals Security Partnership, an Early Warning System for supply chains, export controls on advanced technology, and information/best-practices sharing (as well as domestic law enforcement cooperation) related to disruptive technologies. Women’s economic empowerment and trilateral scientific laboratory cooperation also featured in the economic/technology section of the Spirit of Camp David.

Cooperation on the Indo-Pacific region made it into the summit joint statement as well, with a focus on trilateral development financing cooperation, maritime security capacity building (notably for Southeast Asia and the Pacific Islands), and the establishment of a humanitarian response policy dialogue. In the realm of global health, the Camp David Spirit document mentions trilateral cooperation on a cancer “moonshot,” while the three states also pledged to set up a Global Leadership Youth summit and a technology leadership training program to promote people-to-people contact.

Arguably, the feature that got the most attention at Camp David was the Commitment to Consult. The signatures of Biden, Yoon, and Kishida on the Commitment to Consult document represent a significant step in strengthening the US-South Korea-Japan trilateral toward a partnership that resembles an alliance. In fact, it is a Type III alliance by the Correlates of War definition (“a commitment obligat[ing] members to consult in times of crisis or armed attack”). The Camp David Commitment to Consult even requires consultation on matters short of “crisis or armed attack”—namely, “challenges, provocations, and threats that affect their collective interest and security.” This seemingly emphasizes the importance of continuous consultation among the three states, an institutionalization of the consultation practice that will be backed up by the regularization of high-level meetings and summits fed by greater (aforementioned) intelligence sharing. To be sure, the Commitment to Consult is not a mutual defense treaty, and does not contain an actionable collective security and defense requirement, but the trilateral does reach the status of a “quasi” or “soft” alliance.

The North Korea nuclear threat is the obvious referent for the trilateral Commitment to Consult—North Korea is referred to multiple times as a threat in the summit joint statement, and denuclearization of North Korea as a key for Korean Peninsula and regional stability. But China is clearly also operating in the background of the consultation commitment, a prospect for Washington-Seoul-Japan quasi-alliance coordination that surely worries Beijing.

Figure 3 In support of the Washington Declaration signed earlier in the year, the US dispatched a nuclear-powered guided missile submarine, which arrived in Busan on June 16, 2023. Photo: Deutsche Welle

Actions accompanied words. The diplomatic flurry of the May-August period was backed up by both US-South Korea and US-South Korea-Japan military exercises. Mid-May set the stage for a summer of high-tempo alliance military cooperation, with major US-South Korea live fire drills to mark the 70^th anniversary of the alliance, followed at the end of the month with an F-16 “elephant walk” display. The US, South Korea, and Japan also publicized plans to link radars to reduce blind spots against North Korean missile launches. June featured US-South Korea joint logistics and live fire drills (the latter in response to a North Korean short-range ballistic missile (SRBM) launch). The US and South Korean militaries also cooperated to successfully salvage components of a failed North Korean satellite launch vehicle (SLV), which has now doubtless been subject to intelligence collection by US and South Korean authorities. This salvage success was not simply fortuitous, as the alliance militaries practiced salvage operations in May, during the lead-up to Pyongyang’s satellite launch. And in an effort to support the Washington Declaration—which, inter alia, commits the US to greater rotation of strategic assets into the Korean Peninsula region—the US dispatched a nuclear-powered guided-missile submarine to South Korea. This was a first since the fire-and-fury tensions of 2017, which indicates the parlous nature of security in Northeast Asia. June finished with the US again following up on its Washington Declaration pledge to enhance extended deterrence, as US and South Korean air forces held combined air drills featuring B-52 nuclear bombers. The emphasis on extended deterrence extended into July, with the inaugural meeting of the Nuclear Consultative Group established in the Washington Declaration and, in addition, US-South Korea air drills with B-52s. These drills followed the July 12 North Korean launch of a solid-fuel ICBM (Hwasong-18)), which led to US-South Korea-Japan trilateral military exercises and missile defense drills. Although perhaps already planned in support of the Washington Declaration, Pyongyang’s successful solid-fuel ICBM launch was followed by the first South Korean port call of a US SSBN (nuclear ballistic missile submarine) since 1981. The US and South Korea also carried out joint air drills with F-35s and F-16s, as well as anti-submarine warfare exercises including the USS Annapolis nuclear-powered fast-attack submarine. Finally, the May-August reporting period finished with US-South Korea-Japan trilateral missile defense exercises and the annual US-South Korea Ulchi Freedom Shield combined military exercises, which this year included the first wartime deployment drills since 2017 and a civil defense component requiring the population of South Korea to shelter in place for a brief period.

Figure 4 South Korean president Yoon Suk Yeol makes a surprise visit to Ukrainian president Volodymyr Zelenskyy in Kyiv on July 15, 2023. Photo: AP/Jae C. Hong

Also on the security/defense front, as a part of Yoon’s participation at the 2023 NATO summit (as a member of the so-called Asia Pacific4 or AP4), South Korea announced indirect ammunition sales for Ukraine (passing through the US), increased intelligence sharing with NATO, and a new suite of 11 cooperation areas with NATO (which will presumably be advanced through the Individually Tailored Partnership Programme that South Korea signed with NATO during the summit). During his swing through Europe for the NATO summit, Yoon took the occasion to visit Ukraine and show solidarity with Kyiv’s war effort. July also saw the US and South Korea sign a new agreement bolstering defense supply chain cooperation.

Beyond security/defense, the US and South Korea engaged in the typically thick set of exchanges—along axes of bilateral/multilateral coordination, economy/trade, countering North Korea, etc.—that are necessary parts of alliance management; thus the typical series of senior officials meetings throughout the May-August reporting period (see chronology below). One notable discussion was US Secretary of State Tony Blinken briefing his counterpart, Foreign Minister Park Jin, both before and after Blinken’s visit to Beijing in an attempt to put a floor under a deteriorating US-China relationship that has major consequences for South Korea. South Korea also won a seat as a nonpermanent member of the UN Security Council for the 2024-2025 term, an effort that was doubtless aided by US diplomatic support.

Diplomacy implies friction also, and a persistent area of tension in US-South Korea relations has been economy/trade, as the US has tried to spur partners to participate in the US-led effort to contain China in high-technology areas, resulting in knock-on effects for South Korea, which is reliant on China as both an input source and export market in several high-tech sectors (in addition to simply being its number one overall trade partner, accounting for about 20% of Korea’s trade volume by value). Throughout the summer US and South Korean trade representatives and other senior officials met to discuss and clarify policies and expectations on semi-conductor exports, critical mineral supplies, the evolution of the US-led Indo-Pacific Economic Framework (IPEF), and the status of the Inflation Reduction Act (IRA). The US and South Korea also discussed further cooperation (both bilaterally and within larger groupings) on high-tech supply chains. No doubt some of these discussions were substantive in and of themselves, but they were also important for clearing up potential disagreements in advance of the Camp David summit, whose joint statement included language on some of these sensitive economic issues.

With a raft of international investments, the private sector did its part to contribute to summertime good vibes, with Hyundai and LG pledging $4.3 billion in a US battery plant, SK Signet announcing completion of its first US factory, Samsung SDI and GM finalizing a battery plant joint venture in Indiana, and Samsung Biologics signing a $400+mn deal with Pfizer, among other deals. In the culture industry space, BTS continued to garner US mind share, as the group’s book Beyond the Story became the first Korean book to top the New York Times bestseller list, while BTS member Jung Kook’s solo album topped the Billboard Top 40. Netflix’s CEO visited Seoul in June, indicating how important South Korea has become as a content source for Netflix series.

A staple of Washington-Seoul diplomacy is the ritual condemnation of North Korea for its many malign acts, including missile tests and other sanctions violations, cyberattacks, and human rights abuses. There were plenty of occasions during the May-August 2023 period: failed SLV launches in May and August; a successful solid-fuel ICBM test in July; SRBM demonstrations in June, July, and August; an August cruise missile demonstration; revelations of Pyongyang’s ongoing cyberattacks to steal cryptocurrency to fund the Kim regime; possible North Korea-Russia rocket sales for use in the Ukraine war; and the lead-up to a UNSC hearing on North Korean human rights violations all occasioned in-person and telephone/video discussions on possible responses (sanctions, condemnation, etc.) between senior administration officials in Washington and Seoul (with numerous discussions including Japanese counterparts as well).

US-North Korea Relations: (Un)happy Days

US-North Korea relations—such as they are—continued their abysmal trajectory during the summer of 2023. A failed end of May SLV launch by Pyongyang opened the summer season, while late August featured an unsuccessful re-do. In principle these SLV launches are intended to allow North Korea to place military satellites in orbit, which might (depending on the satellite’s camera resolution, inter alia) give the Kim regime better awareness of US-South Korea military developments. The SLV failures are expensive setbacks, but not unexpected. Pyongyang publicly acknowledged the failures, indicating a certain comfort with admitting SLV program growing pains and/or a strategy of “normalizing” the use of SLV technology. Pyongyang likely has learned from the failures, bringing them closer to functioning military satellites.

Pyongyang’s misbehavior led to the standard coordinated US-South Korea response (along with Japan) noting the SLV launches as violations of international sanctions; investigating and implementing new sanctions; attempting to rein in North Korean cybersecurity breaches (notably cryptocurrency theft) that fund the regime’s military activities; and condemning the launches at the UNSC (as well as at the NATO summit), albeit fruitlessly given Chinese and Russian support for North Korea at the UNSC. Beyond an alliance military riposte (including trilateral drills with Japan), Washington and Seoul also cooperated in salvage operations of components of both failed SLVs, which splashed down in the Yellow Sea. Technical analysis of the SLV may give the US and South Korea a better idea of the state of North Korea’s rocket and satellite technology, as well as an idea of where parts nonindigenous to North Korea may have originated.

Figure 5 North Korea successfully conducted a second flight test of the Hwasong-19 solid-propellant intercontinental ballistic missile on July 12, 2023. Photo: Korean Central Television

North Korea’s weapons development programs also proceeded apace during summer 2023. Although the long-speculated seventh nuclear test remains unexecuted, Pyongyang did launch numerous SRBMs and cruise missiles, as well as a successful solid-fuel ICBM (Hwasong-18) that in principle gives the Kim regime greater reliability, survivability, mobility, and flexibility in its ability to attack intercontinental-range targets (such as the US) with nuclear weapons. Although the usual caveats apply—unknown guidance system, re-entry vehicle reliability, penetration aids, deployment status, etc.—the Hwasong-18 likely represents a meaningful, if marginal, improvement to North Korea’s nuclear arsenal. Wanting to avoid the appearance of normalization of Pyongyang’s weapons development, the US and its East Asia alliance partners were in lockstep in condemning the missile demonstrations/tests and imposing new sanctions, which naturally occasioned fiery rhetoric from the Kim regime, lambasting the US for imperialist policies of regional domination, castigating South Korea for its supposed “lap dog” status, and promising development of increasingly powerful nuclear weapons.

North Korean missiles were not the only game in town in terms of weapons. Pyongyang’s annual Armistice Day parade featured drones (strikingly similar to US-made Reapers and Global Hawks) both on display and in demonstrations. Kim Jong Un toured munitions factories, announced updated military actions plans against the US-South Korea alliance, and visited the KPA Navy to pledge nuclear weapons for that service branch. Presumably in part as a tit-for-tat in the context of US-South Korea Ulchi Freedom Shield combined military exercises, late August also saw North Korea drill for offensive military operations against South Korea, including both cruise missile tactical nuclear strikes and occupation of South Korean territory.

Armistice Day welcomed to Pyongyang two international delegations from China and Russia. This was, on the one hand, a standard diplomatic gesture among like-minded, aligned states. On the other hand, the presence of international delegations for the festivities functioned (a) to signal that North Korea was slowly re-opening after 3+ years of COVID shutdown, and (b) to provide an opportunity for North Korea and Russia to discuss weapon sales from Pyongyang to Moscow. North Korea has apparently re-opened in a limited fashion (including regularly scheduled flights and ground transportation, currently only for returning citizens), with trade with China and Russia likely to pick up. At least some of that trade is slated to involve weapons, as US intelligence has reported ongoing Russia-North Korea negotiations for the former to purchase artillery and other arms from the latter. US intelligence believes that Kim Jong Un is to travel to Vladivostok to meet with Russian President Vladimir Putin to make critical final progress on the arms deal, which might include, from the Russian side, food assistance, satellite technology, and perhaps even nuclear-propulsion technology for submarines. Such a deal would doubly vex the US: Russian use of North Korean artillery in Ukraine could make it harder for Washington to assist Ukraine in winning enough militarily to force Moscow to the negotiation table, while Russian satellite and submarine nuclear-propulsion technology in Pyongyang’s possession could provide it with qualitative military improvements that would complicate US-South Korea deterrence and warfighting strategies around the Korean Peninsula.

Finally, in the various and sundry category, an apparently troubled US enlisted soldier—Travis King—fled over the military demarcation line (MDL) at Panmunjom and was taken into North Korean custody. His precise whereabouts and condition are unknown (at least publicly), as is the motive for his actions. Diplomatic efforts to secure his release and return have not born fruit.

Conclusion: Good Times vs. The Bad News Bears

Washington-Seoul relations are arguably at a high point in history, even to the point of the bilateral alliance flirting with transformation into a trilateral structure. There is no guarantee that the institutionalization of US-South Korea-Japan cooperation will continue, as there are still unresolved historical issues (for Seoul and Tokyo) and potential domestic political pitfalls (for all three states). However, threats from China and North Korea have developed such that the US, South Korea, and Japan have sufficiently overlapping security fears to move forward on security and defense cooperation that was hard to imagine even two years ago.

For its part, North Korea finds itself in a closer constellation with China and Russia. Speculation, over the last several years, that a China-North Korea-Russia bloc would emerge from the regional/global destabilization caused by increased US-China great power competition and Russia’s war of aggression again Ukraine has been born out. Not only does this tightening of authoritarian bonds make US-North Korea relations even harder to jump-start than they already are, but it potentially represents a force multiplier for the various interests of Kim, Putin, and Xi. This both increases the regional threat to the US-South Korea alliance, and makes that alliance (and its trilateral transformation) all the more critical.

Chronology by Olena Guseinova