This policy research paper examines post-war Security Sector Reform (SSR) in South Korea, focusing on strategies of external and internal balancing in a prolonged context of geopolitical tension.

Externally, South Korea relied on a military alliance with the United States to deter aggression from North Korea. This alliance provided strategic security guarantees and allowed South Korea to invest in economic development and post-war reconstruction without excessive militarization. However, it also required South Korea to compromise some sovereignty through a joint military command.

Internally, South Korea strengthened its defense capacity through reforms that transitioned from a troop-intensive to a technology-intensive military structure. Civilian control over the military was gradually institutionalized, though occasionally challenged by military coups in earlier decades. Democratic accountability was eventually reinforced through constitutional and institutional reforms.

South Korea’s post-war reconstruction has been widely regarded as remarkable due to its successful transformation from the ashes of the Korean War to one of the world’s major economic and military powers.

Despite persistent threats across the Military Demarcation Line, South Korea has balanced deterrence and democratic governance, avoiding the full transformation into a garrison state.

The South Korean experience illustrates how sustained external support, combined with internal reforms aimed at efficiency and accountability, can help post-war states like Ukraine maintain sovereignty and democracy in the face of militarization pressures. Lessons from South Korea offer important insights for SSR in similarly vulnerable post-conflict environments.