Amidst the growing U.S. rift with various allies in Europe and even the Indo-Pacific, such as Japan and Australia, South Korea must reassess its national security. With North Korea ever more emboldened, the Republic of Korea (ROK) must prepare concrete contingencies to defend the country from future war.
With lukewarm messaging from Seoul’s top ally and political turbulence, the ROK needs a concrete strategy and doctrine to promote deterrence and diplomatic peace through strength. With growing global threats in Europe, the Middle East, and the Indo-Pacific—particularly on the Korean Peninsula—Seoul should adopt a new foreign policy of strategic ambiguity toward Pyongyang, keeping the North guessing what the Republic’s future moves could be.
Growing American Turbulence in Foreign Policy
Russia’s full-scale invasion of Ukraine in 2022 changed foreign relations for the better and worse, as many of the world’s top military powers reassessed national security concerns. Under the Biden Administration, relations improved with South Korea, and historical summits between Washington, Seoul, and Tokyo occurred.
However, the slow trickling of military aid to Ukraine and then-President Biden’s lack of a concrete strategy made countries worry if America would truly back its allies. Those fears so far have come to fruition under President Trump, who is not only struggling to bring Russian autocrat Vladimir Putin to the negotiating table with Ukraine but whose cabinet has engaged in diplomatic incidents in both Europe and Asia, as noted in an April 2025 article by the Center for American Progress.
Already suffering from political turbulence in the aftermath of former President Yoon’s attempted coup and martial law, Seoul should also be wary of the lack of American indecisiveness towards its allies, even when the US-ROK alliance remains steadfast.
An Ever-Emboldened North Korea
While the U.S. and its allies fluctuate between steadfast support and diplomatic conflicts, its adversaries become more emboldened by the day. One of the primary beneficiaries of American indecisiveness is North Korea. Not only has Pyongyang self-sabotaged reunification efforts with Seoul, but the Kim regime is also actively preparing for an armed conflict.
During the past couple of years, North Korea has ramped up ballistic missile tests and drone production and ordered the Korean People’s Army (KPA) to have capabilities for war. Furthermore, Pyongyang came to Moscow’s aid, both through logistics and boots on the ground, which both the DPRK and Russia acknowledged.
In the late Autumn of 2024, North Korea sent several thousand KPA contingents to Russia to use their operations to take back the Kursk region, in which Ukraine established a foothold that same summer. Wanting combat experience and valuable data, the KPA rushed forward at any chance during assaults, albeit taking heavy casualties due to a lack of experience and language barriers with the Russian forces.
In a March 2023 analysis with NK News, Chris Monday, a specialist in Russian strategy, noted the Kim regime approved of using North Korean troops in Kursk to gain a reputation as ‘skilled warriors.’
Despite significant casualties, KPA troops helped Russian forces enough to regain the Kursk region, and DPRK forces could take part in further operations inside Ukraine if requested. In an April 2025 article by Stimson Center’s 38 North, Kim Jong Un’s acknowledgement of direct intervention in Kursk was to solidify the growing mutual defense pact between the DPRK and Russia, which is an increasing threat to stability in Ukraine and South Korea.
Should South Korea Reconsider a Nuclear Deterrence?
Amidst North Korea’s rising capabilities and political turmoil in the South and the United States, Seoul must prepare for possible provocations by Pyongyang, which could test the waters of American commitments to its allies, with relations fractured over the past several months. However, South Korea could counter a potential surprise attack from the North by potentially moving forward with plans for nuclear deterrence.
Initially, in the 1970s, South Korea started to develop nuclear weapons, and historically, society saw their use in a positive manner that ended brutal Imperial Japanese rule. Under U.S. pressure, Seoul ceased nuclear ambitions fully under the 1992 Summit, but Pyongyang continued to secretly proliferate until it achieved nuclear weapons itself in the late 90s, nonetheless.
The tide of the world has changed as Russia has strong-armed the world over the past few years with nuclear threats, which its new security partner, North Korea, would attempt to replicate over the Korean Peninsula.
Suppose Ukraine were to be forced to cede territory over the threat of Russian nuclear weapons hitting Europe and America. What could stop the same thing if China conducted the same strategy towards Taiwan, Japan, or the South China Sea, and North Korea towards South Korea?
Here lies the conundrum of nuclear extortion, where non-nuclear states facing aggression from nuclear powers would feel inclined to gain their weapons of mass destruction as a last-ditch deterrence.
Arguments Against Nuclear Weapons for South Korea
Growing alliance shifts could make Seoul reassess whether Washington would protect the Republic with a counterstrike if the North launched a first strike. For this reason, arguments are being made for a potential independent proliferation program. Nevertheless, if the ROK’s government moves forward with a program, there will be questions and concerns.
Firstly, if the production of nuclear weapons takes place, North Korea would realize it would lose its edge on weapons of mass destruction. Because of those fears, Pyongyang may be inclined to conduct military and clandestine operations to prevent a new program in Seoul. South Korea’s government could also encounter international pressure and further diplomatic coercion by the United States to impede the program.
Lastly, former President Yoon’s activities showed the need for further checks and balances, as his actions nearly led to not only a renewed military dictatorship in South Korea’s history but also a probable all-out war. Fears of another rogue and despotic government, this time with nuclear weapons, could stoke fears and contingency planning towards proliferation.
South Korea’s younger generation is more politically active for unification and has now witnessed limited martial law. Fears of growing militarism could push for internal political pushback by Generation Z and millennials.
Adopting Strategic Ambiguity Going Forward
Despite domestic challenges, growing regional threats, and turbulence among allied partners, South Korea can maintain its edge in defense and deterrence by officially enacting strategic ambiguity as its foreign policy progresses.
Pyongyang and much of the world see Seoul as a rational actor who would never commit the unthinkable. Even when Yoon attempted to enact martial law, as military officers testified during the former President’s trial, South Korean citizens and parliament fought back—but what if the government capitalized on this with the North?
North Korea and Russia are directly benefiting from the unwillingness of various nations to confront their belligerent actions with empty words and hollow rhetoric, which South Korea was intertwined in as the KPA gained combat experience in Kursk.
Enacting strategic ambiguity, Seoul could keep Pyongyang guessing whether it will or will not decide to pursue its independent nuclear program. Still, this type of foreign policy would have to include breaking norms.
Recommendations
In a world of ever-changing alliances, regional wars in Europe and the Middle East, and brewing conflicts in the Indo-Pacific, South Korea should prioritize strategic ambiguity as a foreign policy priority. By matching or eclipsing North Korea’s unpredictability, Seoul can match its top existential threat while restoring domestic democratic order.
While maintaining top-level diplomacy and soft power, Seoul should carry a foreign policy equivalent to Teddy Roosevelt’s, with ambiguity regarding future movements. Adopting this policy could dislodge the Kim regime from its plans as it tries to decipher what the ROK is planning, as the North would assume Seoul is still reeling from political instability, and this could play into the Republic’s hands in guessing the ROK’s next moves instead of vice versa.
Recommended policy implications should include growing trilateral intelligence between South Korea, Japan, and the United States regarding North Korea’s missile tests and briefings on Russia’s partnership with the DPRK. Strengthening democratic safeguards and simultaneously preparing the military and civil defense for external and internal instability on the Korean Peninsula is tantamount to regional security in the Indo-Pacific.
