South Korea's Continued Political Polarization

Lee Jae-myung’s foreign policy successes
in the shadow of political polarisation

by Daniel Sneider, lecturer in East Asian studies at Stanford University, non-resident distinguished fellow at the Korea Economic Institute of America, and APP Member. First Published January 18, 2026 on the East Asia Forum.

South Korean President Lee Jae-myung came into power in an early unscheduled election in June 2025, under perhaps some of the most trying circumstances to face a South Korean leader in the past decade.

The election followed a failed attempt to declare martial law by then-president Yoon Suk-yeol, followed by his impeachment, deepening a political divide that spilled out into the streets of the capital and beyond. The new leader was immediately faced with a trade war from the United States, South Korea’s security ally led by President Donald Trump, that threatened to upend the economy. At the same time, Lee had to shape a policy to balance relations with China and Japan alongside a belligerent and well-armed North Korea, closely tied to Russia and its war in Ukraine.

Yet Lee has exceeded the expectations of many observers of South Korea’s turbulent politics. The leader of the progressive Democratic Party has proven himself to be not only a consummate pragmatist, as some predicted, but even more surprisingly a deft diplomat as well.

In January 2026, Lee managed a highly successful summit in Beijing, followed shortly by a surprisingly warm and positive trip to Japan hosted by Prime Minister Sanae Takaichi. All along, he avoided getting drawn into the sharpening confrontation between Japan and China.

In the year ahead these diplomatic gains may be overshadowed by the continuing — even sharpening — lines of political polarisation domestically. There is a double divide in South Korean politics. On one level, it exists between the ruling progressives and the conservative opposition People Power Party. Both camps themselves are also split between ideological extremism and more centrist elements.

The South Korean right is increasingly at odds with itself, pitting the hardline followers of former president Yoon, who have adopted the rhetoric and imagery of Trump’s Make America Great Again movement, against the conservatives who crucially broke with Yoon’s martial law bid. On the left, the Lee administration is dominated for now by advocates of pragmatism, not only in the realm of foreign policy but also in fostering the support of chaebols. There are though, more ideological leftists within its ranks and in the membership of the party’s National Assembly bloc.

Those divides are tested by Lee’s increasingly aggressive pursuit to prosecute the leaders and supporters of Yoon’s insurrection, not only through the courts but also via his attempts to regulate conspiracy-driven social media. In the name of defending democracy, the administration has also targeted the Unification Church and other right-wing evangelical movements.

Former US ambassador to South Korea Kathleen Stephens noted that Lee’s actions on these fronts, alongside the perception of his party as being ‘dangerously soft on North Korea’, have led him to be ‘viewed with deep distrust by many [South] Koreans’.

This deepening polarisation will begin to impact not only domestic stability but also the conduct of foreign policy. This is already evident in the difficult job of balancing relations with China, favoured by many on the left but denounced on the right, with increasing unease among progressives over American unilateralism and isolationism.

Lee made significant concessions on trade and investment issues in talks with the Trump administration to preserve the security alliance, though he can claim to have won a better bargain than Japan on both fronts. South Korean negotiators pushed the timetable for the long-sought transfer of wartime operational control of armed forces and made a deal to construct nuclear-powered submarines that could lead to a revision of restrictions on nuclear fuel enrichment and reprocessing. But even within the Lee administration, there is unhappiness over a shift in the focus of US military presence towards contingencies for confrontation with China.

‘Traditional leftist orientations on major domestic and foreign policy issues are colliding with very different geopolitical and geo-economic drivers that Lee has to accommodate’, argues Chung Min Lee. The South Korean right also faces significant challenges, remaining ‘shell shocked and in near-total disarray’ with no ‘viable party leadership and agenda’.

The looming question that may push these divisions to the forefront, not least within the Lee administration itself, is how to respond to North Korea’s growing confidence in its power. Progressive advocates of engagement, led by Unification Minister Chung Dong-young and National Intelligence Service Director Lee Jong-seok, are pushing for more attempts to woo Pyongyang, even towards de facto acceptance of its nuclear status.

But this outreach is frustrated by North Korea’s dismissal of their legitimacy. The administration seeks to use improved ties to China to open dialogue with the North Korean regime but Pyongyang seems to prefer relying on its new alliance with Russia and waiting to see what Trump may offer them. Even if Trump’s Beijing visit in April 2026 were able to help foster inter-Korean relations, there is no guarantee that North Korean Supreme Leader Kim Jong-un will have a dialogue with Seoul.

Policy choices that were deferred will come to the fore in 2026 and bring the double divide of South Korean politics into play. Lee ‘will be walking on a tightrope’ — evidence so far suggests he may be up to the task, but time will tell.