South Korean President Lee Jae Myung used a cabinet meeting on Tuesday to direct officials to accelerate the transfer of wartime operational control from the United States and to proceed with a nuclear-powered submarine program, framing the moves as a response to President Donald Trump’s decision to sharply reduce joint military exercises.
The Ulchi Freedom Shield drills, which began August 17 and run through August 27, were cut from 22 battalion-level field events last year to 14 this year before Trump ordered further curtailment. Lee’s push comes as Seoul and Washington prepare to evaluate full operational capability for a future combined command in November 2026.
The conditions for transferring wartime command have been sitting on a shelf in Seoul since 2018, waiting for a political moment that never quite arrived. On Tuesday, Lee Jae Myung decided the moment had arrived. Lee told his cabinet that South Korea’s military and industrial strength demanded faster progress on two long-stalled projects: regaining wartime command and building nuclear-powered attack submarines. He did not mention Trump by name. He did not need to. Trump’s order to substantially reduce the Ulchi Freedom Shield exercise, now underway, had already made the case for him.
“South Korea is ranked among the world’s top five military powers and is considered one of the world’s top four defence industry powers,” Lee said, framing the self-reliance push as a natural extension of that standing. The question now is whether Washington will treat Lee’s acceleration as a partner stepping up or as an ally stepping away.
The submarine plan that was waiting for a crisis
Seoul’s Ministry of National Defense adopted a formal roadmap for nuclear-powered submarines on May 26, 2026. The Jang Bogo N project targets a first boat launch in the mid-2030s and operational service by the late 2030s, using domestically built hulls and low-enriched uranium fuel. A special act now before the National Assembly would codify five principles: fuel below 20% enrichment, non-proliferation pledges, no nuclear weapons, indigenous construction of three roughly 8,000-ton attack submarines, and reliance on U.S. consent under the 123 Agreement for fuel supply.
The wartime command transfer follows its own rigid calendar. Seoul and Washington are conducting a three-stage verification process. Full Operational Capability of the future combined command is scheduled for evaluation at the annual Security Consultative Meeting in Washington this November. Defense ministers then intend to propose a specific transfer year to both presidents. The entire sequence is conditions-based: South Korea must prove it can lead the combined defense, the alliance must field a credible response to North Korea’s nuclear and missile threats, and the security environment on the peninsula must support a stable handover.
“The Trump administration treats alliances as transactional investments,” said Leif-Eric Easley, a professor at Ewha Womans University in Seoul. “South Korean leaders must constantly renegotiate economic and security issues, making Seoul cautious but determined to strengthen both self-reliant defense and its U.S. ties.” A South Korean Joint Chiefs official, briefing local media, explained that this year’s combined drills consolidate battalion-level field exercises and spread them across the year, focusing on essential scenarios tied to Ulchi Freedom Shield—a shift toward leaner but more targeted training.
The conditions that have always governed the transfer
The OPCON transfer has been a recurring friction point since the two countries first agreed to a conditions-based plan in 2014. Each time U.S. commitment appeared to waver—during the Trump administration’s first term, during budget fights, during the pandemic—Seoul quietly accelerated its own preparations. The difference now is that Lee has a formal submarine roadmap, a dedicated project team created in August, and a November evaluation that could lock in a transfer year. The 123 Agreement, updated in January 2025, still bars South Korea from enriching uranium or reprocessing spent fuel without U.S. consent, so the submarine program’s fuel supply depends on negotiated approvals that Washington can slow or condition.
Japan is likely to deepen its own undersea and missile-defense investments, citing South Korea’s nuclear-submarine plans as another reason to expand its fleet. China can be expected to condemn the Jang Bogo N program as destabilising and tighten surveillance in the Yellow and East China Seas. North Korea is already portraying reduced drills as evidence of U.S. weakness and will likely use any ROK nuclear-submarine milestones to justify further missile and tactical nuclear deployments.
The November meeting in Washington will be the first test of whether Lee’s acceleration is a partner stepping up or an ally stepping away.
Beyond the headline
The Power Behind It
The real leverage in this shift sits with the bureaucracies that certify capability, not just with presidents’ rhetoric. South Korea’s defence ministry and the U.S. Pentagon can quietly accelerate or slow OPCON transfer and submarine approvals by how they score readiness, interpret conditions, and schedule evaluations, effectively deciding how far Lee’s self-reliance agenda can go regardless of public alliance assurances.
The Timing
Lee is moving just as long-planned milestones converge: a formal nuclear-submarine roadmap adopted in May, dedicated project teams created in August, and the Full Operational Capability check scheduled for November. Trump’s sudden drill cuts arrive into this pre-set calendar, giving Seoul a narrow window in 2026 to lock in decisions before U.S. election dynamics or North Korean provocations reshape the alliance agenda.
The Reach
One non-obvious ripple could run through the U.S. Navy’s Pacific posture. If South Korean nuclear-powered submarines eventually patrol beyond the peninsula—a possibility analysts suggest could emerge from ongoing Seoul-Washington discussions on potential South Korean contributions to regional security—they could alter undersea surveillance patterns and burden-sharing expectations across contested waters, potentially allowing Washington to reallocate some U.S. attack submarines while also complicating deconfliction and intelligence-sharing rules that were designed around a single nuclear-sub fleet in the alliance.
What a more autonomous Seoul means for Washington, investors, and the Navy
With the November evaluation approaching and the submarine legislation pending, the alliance is entering a period where bureaucratic decisions will carry as much weight as political declarations.
- US Defense Contractor with APAC Exposure
Evaluate the potential for reduced sales of major defense platforms to South Korea and identify niche opportunities in combat systems, sensors, or nuclear-safety support for the Jang Bogo N program. Monitor South Korea’s Ministry of National Defense English-language announcements for progress on the submarine program and any special legislation introduced in the National Assembly.
- US Diplomat or Policy Analyst focused on Northeast Asia
Assess the implications of a more militarily autonomous South Korea on U.S. foreign policy objectives in Northeast Asia, including alliance management, burden-sharing, and regional stability. Follow the U.S. Department of Defense updates on Ulchi Freedom Shield and alliance exercises via the Pentagon’s official news releases to gauge how far Trump’s reduction order is implemented and whether combined training patterns change over the next year.
- Investor in South Korean Defense Industry
Research South Korean defense companies involved in naval shipbuilding, nuclear technology, or command and control systems to identify potential investment opportunities or risks associated with these policy shifts. Pay particular attention to firms positioned to supply the Jang Bogo N program or benefit from increased domestic spending tied to OPCON transfer preparations.
- US Naval Strategist or Planner
Analyze how a South Korean nuclear submarine fleet might integrate into or complicate existing U.S. naval strategies in the Indo-Pacific, particularly concerning force allocation and operational coordination. The potential for independent ROK submarine patrols in contested waters could require updated deconfliction protocols and intelligence-sharing agreements.
FAQ
What is the status of discussions about South Korea contributing to freedom of navigation in the Strait of Hormuz?
According to Lee’s office, Seoul and Washington are discussing practical and military contributions South Korea could make to help restore freedom of navigation in the Strait of Hormuz. Officials have not committed to a specific deployment but say options are being reviewed alongside legal and readiness considerations, suggesting any decision would likely involve adapting existing naval units rather than creating a new mission from scratch.
What would OPCON transfer mean in practice for U.S. troops stationed in South Korea?
Under the conditions-based plan, OPCON transfer would put a South Korean four-star in charge of the future combined command in wartime, with the U.S. general as deputy, but U.S. forces would remain stationed in South Korea under American national command. In practice, U.S. personnel would still operate under U.S. law and rules of engagement, while warfighting plans and operational orders would be issued through a command structure led by Seoul rather than by a U.S. commander.
Can South Korea export nuclear-powered submarines or related technology?
The Jang Bogo N program is framed as a domestic industrial project, with construction and reactor development led by Korean firms. However, the U.S.–ROK 123 Agreement and related U.S. export controls bar South Korea from re-exporting U.S.-origin nuclear fuel or sensitive technologies and constrain how much submarine nuclear know-how can be shared with third countries. Any future export of ROK nuclear-powered boats or reactors would require separate clearances, limiting direct spillover into foreign sales.
Explainer
- OPCON
- Wartime operational control is the authority to direct military forces in combat. Since the Korean War, a U.S. general has held OPCON over South Korean troops during hostilities, though peacetime control was transferred in 1994. The two allies have been negotiating a conditions-based handover since 2007, with the current plan requiring Seoul to demonstrate full capability to lead the combined defense.
- Ulchi Freedom Shield
- An annual joint command-post exercise between South Korea and the United States, typically held in August. It replaced the earlier Key Resolve exercise in 2019 and focuses on computer-simulated scenarios to test allied readiness against North Korean threats. The 2026 iteration was planned as an 11-day drill with reduced field training before President Trump ordered further cuts.
- 123 Agreement
- The U.S.–ROK civil nuclear cooperation agreement, updated in January 2025, governs the transfer of nuclear material, equipment, and technology between the two countries. It restricts South Korea from enriching uranium or reprocessing spent fuel without U.S. consent, directly shaping the fuel supply and non-proliferation framework for Seoul’s nuclear-powered submarine program.
- Jang Bogo N
- South Korea’s program to develop and build three domestically constructed nuclear-powered attack submarines, named after a Silla-era admiral. Adopted as a formal plan in May 2026, it targets a first launch in the mid-2030s using low-enriched uranium fuel and requires a special legislative act to codify non-weapons commitments and U.S. consent under the 123 Agreement.
- Conditions-Based OPCON Transition Plan
- The bilateral framework agreed in 2014 that sets three conditions for transferring wartime command: South Korea’s ability to lead the combined defense, the alliance’s capacity to counter North Korea’s nuclear and missile threats, and a stable security environment on the peninsula. Progress is evaluated through phased capability assessments tied to major exercises and the annual Security Consultative Meeting.
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