Inter-Korean Relations

A reunion meeting of divided families, courtesy of Divided Families Foundation via Wikimedia Commons

Author: Daniel Wertz

Last Updated by Andrew Yeo
September 2023 & June 2026

Background and Introduction

Korea claims a history that goes back thousands of years, despite past invasions by its neighbors including the Chinese, the Mongols, and the Japanese. Although there have been several periods of competing kingdoms co-existing on the Peninsula over the course of Korea’s long history, Korea’s last dynasty, the Choson Dynasty (1392-1897), ruled over a unified and highly ethnically homogeneous state for over 500 years. Facing pressure from Western powers and Japan in the late 19th century, however, Japan eventually annexed Korea in 1910, subjecting Korea to 35 years of colonial rule until the end of World War II.

In the closing days of World War II in August 1945, the Soviet Union and the United States agreed to a temporary division of the Korean Peninsula at the 38th Parallel until a provisional government could be established. However, plans for placing a unified Korea under international trusteeship were scuttled by the emerging Cold War politics. Elections held in the South led to the establishment of the Republic of Korea (ROK) on August 15, 1948, headed by President Syngman Rhee. Communists in the North followed suit, forming the Democratic People’s Republic of Korea (DPRK) a month leader led by Premier Kim Il Sung. The modern division of the country at the 38th Parallel was based on geopolitical considerations and not on any pre-existing geographic or cultural divisions within Korea.
 

Inter-Korean Relations During and After the Cold War

War broke out on June 25, 1950, with the North Korean People’s Army (KPA) invading and quickly occupying much of the southern half of the Peninsula. The United States soon intervened in the conflict under the aegis of the United Nations Command (UNC), which was followed by the intervention of the Chinese People’s Volunteer Army. Peace negotiations began in 1951 as the war stalemated roughly along the 38th Parallel. After more than three years of fighting, on July 27, 1953, the UNC (represented by the United States), the KPA, and the People’s Volunteer Army signed an Armistice Agreement establishing a demilitarized zone (DMZ) across the Peninsula.1 While the Republic of Korea was represented in the Armistice as a member of the UNC, its military was not a direct signatory. The Armistice left several issues unaddressed, such as a maritime boundary between the two Koreas and a peaceful settlement to the Korean War. 

The scale of destruction and brutality of the Korean War intensified the enmity between the two Koreas. In the years after the war, North and South Korea competed for legitimacy and international recognition abroad, with a developmental dictatorship emerging in the South and a highly centralized personalist regime in the North. For the next few decades, government-to-government contact between the two Koreas was almost nonexistent. In the late 1960s, a number of clashes along the DMZ, and the attempted assassination of ROK President Park Chung-hee in January 1968,2 increased inter-Korean tensions to their highest point since the war.

However, with U.S.-China rapprochement fundamentally changing the security architecture of East Asia in the early 1970s, Seoul and Pyongyang found it in their interests to begin a dialogue with one another. Inter-Korean talks, initially held under the auspices of the Red Cross, led to the first Joint Statement on reunification, issued on July 4, 1972. Yet this détente on the Peninsula was short-lived. In August 1974, the ROK’s First Lady, Yuk Young-soo, was killed during another unsuccessful assassination attempt on Park, carried out by a Japanese-born North Korea sympathizer.3 North Korean agents also attempted to assassinate Park’s successor, President Chun Doo-hwan, during a state visit to Myanmar that killed seven South Korean senior officials in October 1983.4 In November 1987, North Korean terrorists bombed Korean Air Flight 858, resulting in 115 fatalities.5 Although episodes of cautious inter-Korean engagement took place in between crises, notably brief reunions of a small number of separated South and North Korean family members in Seoul and Pyongyang in 1985, such periods of dialogue failed to produce sustained rapprochement.6

Significant inter-Korean dialogue resumed under South Korea’s first democratically elected President, Roh Tae-woo (1988-1993). Roh’s policy of Nordpolitik led to South Korea’s establishment of diplomatic relations with North Korea’s traditional major allies, the Soviet Union and China. As part of this policy, the Roh administration also reached out diplomatically to North Korea, permitting direct inter-Korean trade in 1989 for the first time (see figure 1) and initiating inter-Korean sports exchanges.7 In December 1991, the two Koreas signed a “Basic Agreement” on reconciliation, nonaggression and exchange and cooperation.8 Shortly afterward, the two Koreas issued a Joint Declaration on the Denuclearization of the Korean Peninsula, pledging not to possess, produce, or use nuclear weapons and prohibiting uranium enrichment and plutonium reprocessing.9  

Inter-Korean relations remained turbulent under Roh’s successor Kim Young-sam (1993-1998). Initially taking a hardline position as the first North Korean nuclear crisis mounted in 1993, Kim changed course and planned a summit meeting with North Korean leader Kim Il Sung. The summit would have been the first meeting of the two Koreas’ leaders since the country’s division. However, Kim Il Sung died a few weeks before the summit was to take place. North Korea's criticism of Seoul for failing to send a condolence message further derailed dialogue.10 North-South relations continued to fluctuate over the next several years over issues including food aid, North Korean submarine incursions, and regional diplomacy.11

The Sunshine Policy 

Kim Dae-jung (1998-2003), a prominent South Korean pro-democracy activist, was elected president of South Korea in 1998 and launched the "Sunshine Policy" to promote reconciliation with the DPRK. As part of this initiative, the ROK government permitted South Korean NGOs, businesses, and private citizens to engage in cross-border exchanges with North Koreans, ramping up bilateral food and fertilizer aid to the North, which was recovering from a devastating famine. Hyundai Asan, a subsidiary of South Korea's Hyundai Group, also began operating tours to Mount Geumgang in North Korea in November 1998.12

The uptick in inter-Korean engagement paved the way for the first presidential summit since the division of the Peninsula (see Table 1). The June 2000 meeting in Pyongyang between Kim Dae-jung and North Korean leader Kim Jong Il in Pyongyang marked a turning point in inter-Korean relations, contributing to a significant shift in South Korean attitudes toward the North and strengthening support for engagement.13 The summit also produced concrete agreements, including plans to hold reunions for separated families and to pursue the development of the Kaesong Industrial Complex (KIC) near the DMZ.14

The Sunshine Policy was premised on separating humanitarian and economic cooperation from political and security disputes. As such, the Kim administration continued engagement with North Korea despite naval clashes near the Northern Limit Line—the disputed maritime boundary between the two Koreas—in 1999 and 2002, as well as the collapse of the U.S.-DPRK Agreed Framework on North Korea’s nuclear program in late 2002. 

Roh Moo-hyun (2003-2008), who succeeded Kim Dae-jung as president of the ROK in 2003, sustained reconciliation efforts with North Korea under the “Policy for Peace and Prosperity.” This policy saw increased bilateral aid and humanitarian assistance from South to North as well as substantial government-sponsored investment in the KIC. However, the Roh administration’s approach to North Korea was complicated by the deepening nuclear crisis on the Peninsula. In August 2003, the first round of Six Party Talks—a series of multilateral negotiations to dismantle North Korea’s nuclear program—was convened in Beijing. Despite some progress in the Six Party Talks, however, the DPRK conducted its first nuclear test in October 2006. In response, South Korea temporarily suspended fertilizer and food shipments to the DPRK, but ROK investment in the KIC continued. 

With the Six Party Talks regaining positive momentum in 2007, President Roh and Chairman Kim held the second inter-Korean Summit in October 2007 in Pyongyang in the final months of Roh’s presidency. The Summit outlined multiple new inter-Korean economic development projects, such as the creation of a West Sea Economic Center in the North Korean port city of Haeju. However, these ambitious projects were never implemented.

Cooling Relations Under Lee Myung-bak

The inauguration of President Lee Myung-bak (2008-2012) on February 25, 2008, marked a significant shift in inter-Korean relations under a new conservative government. Before taking office, Lee signaled that he would adopt a more “pragmatic” approach toward North Korea.15 His "Denuclearization, Openness, and 3000" initiative promised to help raise North Korea's per capita income to $3,000 if Pyongyang abandoned its nuclear program and embraced economic reform. Unlike the Sunshine Policy, the initiative more explicitly linked inter-Korean aid and cooperation to denuclearization. Lee also pledged to place greater emphasis on North Korean human rights as part of South Korea's policy toward the North. 

Upon taking office, the Lee administration sharply reduced aid to North Korea while maintaining inter-Korean cooperation through the KIC and Mount Geumgang tourism project. Relations deteriorated, however, after a South Korean tourist was shot and killed in a restricted area of Mount Geumgang in July 2008. Lee suspended tours to the resort pending a joint investigation, but North Korea refused to participate.16

Inter-Korean relations continued to deteriorate in early 2009. North Korea declared all past inter-Korean agreements “nullified,”17 and the Lee administration condemned the North’s nuclear and missile tests. However, Lee did not shutter the KIC despite the worsening atmosphere between the two Koreas, viewing it as an important channel for maintaining dialogue between the two Koreas.18

A new opening in inter-Korean relations arose in August 2009 when North Korea sent a high-level delegation to Kim Dae-jung’s funeral; the delegation subsequently met with President Lee.19 During this time, North Korea released a South Korean worker who had been detained at Kaesong20 and the two Koreas convened a reunion of separated families for the first time since 2007.21  However, this would prove to be another short-lived episode of détente. 

In November 2009, ships from the North and South Korean navies engaged in a skirmish along the Northern Limit Line, the first such clash in seven years. The following March, a South Korean corvette, the Cheonan, sank after an explosion, killing 46 South Korean sailors. An international investigation of the incident reported that “the evidence points overwhelmingly to the conclusion that the torpedo was fired by a North Korean submarine.”22 North Korea rejected the report,23 and some South Korean and U.S. scholars also questioned the investigation.24 China did not assign culpability to the sinking, a stance echoed in the UN Security Council Presidential Statement issued in response.25 Lee demanded a North Korean apology for the attack, and on May 24, 2010 he announced several new unilateral sanctions: the ROK prohibited North Korean ships from using shipping lanes that crossed ROK territory, and suspended all inter-Korean trade and exchanges outside of the KIC.26 In November 2010, as the ROK conducted live-fire military exercises near the NLL, the DPRK military fired approximately 170 artillery shells at Yeonpyeong Island, resulting in the deaths of two South Korean soldiers and two civilians.27

Inter-Korean relations for the remainder of Lee’s Presidency remained tense. South Korea demanded an apology for the Cheonan and Yeonpyeong incidents as a precondition for resuming dialogue, which North Korea refused to give.28 The two sides held secret talks initiated by the South in April 2011 in Beijing, but this attempt at rapprochement was unsuccessful.29 Following Kim Jong Il’s death in December 2011, the ROK issued a statement “convey[ing] sympathy to the North Korean people,” but did not send an official delegation to Pyongyang.30 After Lee condemned North Korea’s April 2012 launch of a satellite using ballistic missile technology, North Korea began an intense personal campaign against Seoul, signaling the end of any interest in dialogue for the remainder of Lee’s term.31

Park Geun-hye's Trustpolitik and Kim Jong Un's Byungjin

Park Geun-hye was elected President of South Korea on December 19, 2012 and vowed to improve relations with North Korea.32 Park campaigned on taking a more pragmatic approach to North Korea, premised on building trust through renewed dialogue while responding forcefully to any new provocations. She also pledged to build a multilateral institution for regional cooperation, which would include North Korea. In a Foreign Affairs essay, Park Geun-hye outlined her vision of trustpolitik, arguing: 

"North Korea must keep its agreements made with South Korea and the international community to establish a minimum level of trust, and second, there must be assured consequences for actions that breach the peace. To ensure stability, trustpolitik should be applied consistently from issue to issue based on verifiable actions, and steps should not be taken for mere political expediency."33

President Park took office amid heightened tensions on the Korean Peninsula. North Korea conducted its third nuclear test in February 2013 and reacted sharply to U.S.-ROK joint military exercises the following month. Over the ensuing weeks, Pyongyang declared the Armistice Agreement “nullified,” severed the last inter-Korean military hotline, and declared a “state of war” with South Korea, while the United States responded by deploying nuclear-capable bombers to the region in a show of force. North Korea also withdrew its approximately 53,000 workers from the KIC, leading South Korea to withdraw its own personnel from the KIC in turn and temporarily suspend operations at the complex.34

The two Koreas gradually returned to dialogue over the next few months, seeking to reopen the KIC and address other issues such as family reunions and the resumption of South Korean travel to Mount Geumgang. Kim Jong Un had himself begun promoting a policy of simultaneous economic and nuclear development (i.e. byungjin line) and was looking to improve the economy with limited economic reforms.35 The two sides achieved a breakthrough in August 2013, agreeing on measures to prevent future disruptions to the KIC and to take steps to develop it further. The agreement committed both Koreas not to restrict employee access or withdraw workers unilaterally, restored communication links, established a joint committee to oversee the complex, and pledged to attract foreign investment.36

Follow-up discussions on the KIC and other inter-Korean issues continued sporadically. In February 2014, the two sides held a reunion for separated families at Mount Geumgang, but talks on resuming tourism to the resort failed to produce an agreement. Working-level negotiations to implement aspects of the KIC agreement also made limited progress.37

Nevertheless, South Korea initiated other elements of trustpolitik by increasing support for UN agencies and NGOs conducting humanitarian work in the North, and by promoting joint projects in areas such as environmental protection and archaeology.38 In November 2014, three high-ranking DPRK officials briefly visited the ROK to attend the closing ceremony of the Asian Games in Incheon, where North Korean athletes were participating.39 However, the visit did not build any momentum for subsequent high-level talks.    

Beginning in 2014, Park Geun-hye shifted trustpolitik in a new direction by placing greater emphasis on Korean unification. At her New Year’s press conference, Park said that “unification is a jackpot,” framing reunification as both a national and economic opportunity.40 Her subsequent speech in Dresden reinforced this message by calling on enhanced inter-Korean exchanges and repeating the benefits of unification.41 DPRK state media criticized this emphasis on unification, interpreting it as a strategy premised on North Korean collapse and South Korean-led unification through absorption.42

North Korea never warmed to trustpolitik, and the policy rang hollow as tensions escalated in inter-Korean relations. In August 2015, two ROK soldiers on patrol in the DMZ were seriously injured by land mines placed outside of their guard posts. A UN investigation concluded that the mines had been deliberately planted by North Korean soldiers, a charge that North Korea denied.43 The ROK government responded by resuming its loudspeaker propaganda along the border, which both sides had agreed to halt in 2004. The North fired four shells into the South in response to this, and the ROK responded with a barrage of artillery fire. Subsequent high-level talks resulted in a compromise: the DPRK expressed “regret” over the injuries, while South Korea agreed to end the loudspeaker broadcasts “unless an unusual incident occurs.”  The two sides also agreed to arrange a new round of family reunions, which was held in October 2015.

In January 2016, North Korea launched its fourth nuclear test followed by a long range ICBM test in February. Park responded by announcing the immediate closure of the KIC that month. In a speech addressed to the National Assembly, Park argued that funds from the KIC had gone to the leadership of North Korea’s Workers’ Party (KWP) and that the security of South Korean workers at the KIC was under constant risk. She added that it had “become indisputably clear that the existing approach and good intentions will by no means work in countering the North Korean regime’s determination to develop nuclear weapons.”44 In addition to shutting down the KIC, the South Korean government announced plans to tighten sanctions on North Korea. Pyongyang responded by placing the KIC under military control, freezing South Korean assets in the complex, and severing military-to-military communication channels with the South.45

Moon Jae-in and a (Brief) Renewal of Inter-Korean Relations

In the wake of Park’s corruption scandal and eventual impeachment in late 2016/early 2017, South Koreans elected the progressive President Moon Jae-in (2017-2022), a human rights lawyer and son of North Korean refugees, in May 2017 after nearly a decade of conservative rule.46 Consistent with past progressive South Korean leaders, Moon advocated for peace and prosperity on the Korean Peninsula through engagement and dialogue. Although the Moon government also applied sanctions to North Korea in response to missile and nuclear tests, it adhered to an approach of unconditional engagement (dubbed by some as “Sunshine Policy 2.0”) even during heightened geopolitical tensions and periods of diplomatic unresponsiveness.47

Moon’s initial efforts at dialogue with North Korea, including offers for humanitarian aid and calls to resume family reunions, were largely met with silence from North Korea. Tensions on the Korean Peninsula accelerated in 2017 as North Korea conducted a series of missile tests, and U.S. President Donald Trump threatened “fire and fury” against the Kim regime.48 North Korea further ratcheted tensions by conducting a sixth nuclear test in September 2017.49 By November 2017, the Kim regime declared that it had become a full-fledged nuclear state with nuclear-strike capability.50

A Thaw in Inter-Korean Relations 
Despite significant U.S.-North Korea nuclear escalation in late 2017, inter-Korean relations (and later U.S.-North Korea relations) experienced a dramatic thaw in 2018 that would lead to three inter-Korean summits between Moon and Kim. During his annual New Year’s Day speech, Kim Jong Un wished South Korea a successful hosting of the upcoming Winter Olympics and signaled greater openness to dialogue.51 In a rapid series of moves, South and North Korean officials reactivated a transborder hotline for the first time in two years on January 3, 2018.52 Six days later, South and North Korean officials held face-to-face talks for the first time since December 2015. During the discussions, North Korean officials rebuffed South Korean efforts to bring up its nuclear program, but both sides reached a deal that allowed Pyongyang to participate in the Winter Olympics and to resume cross-border military communications.53

The February 2018 Winter Olympics in Pyeongchang provided an opportunity for both sides of the Peninsula to come together in a show of unity on the world stage. North and South Korean athletes marched together under a “unified Korea” flag during the opening ceremony and fielded a joint women’s ice hockey team.54 Kim Jong Un’s sister, Kim Yo Jong, and a high-level North Korean delegation attended the opening ceremony and delivered a rare invitation to Moon to visit Pyongyang for a summit.55

To sustain diplomatic momentum, South Korean National Security Advisor Chung Eui-yong led a 10-member delegation to Pyongyang to meet Kim Jong Un to discuss improving inter-Korean ties and persuade the leader to pursue dialogue with the United States.56 Subsequently, then-U.S. CIA Director Mike Pompeo traveled to Pyongyang in April of 2018 to meet with Kim Jong Un in preparation for a potential summit between Trump and Kim to possibly reinvigorate bilateral nuclear talks.57 Two days later, Kim Jong Un announced that he would stop nuclear and missile testing and shut down the Punggye-ri nuclear test site, but made no mention of giving up nuclear weapons. The declaration came ahead of a meeting with Moon and served as a precursor to a bilateral meeting with Trump.58

Adding to the momentum, on April 27, 2018, Kim Jong Un crossed the border into South Korea for a historic inter-Korean summit held at the Peace House in Panmunjom, becoming the first North Korean leader to set foot on South Korean soil.59 Both leaders agreed to work toward “complete denuclearization of the Korean peninsula” and vowed to declare an official end to the Korean War within a year. They also signed the Panmunjom Declaration for Peace, Prosperity and Unification of the Korean Peninsula, which called for the end of military activities around the region, establishment of a joint-liaison office in the Kaesong area, and the reunification of Korea.60 The Declaration marked a high-point in Moon’s diplomatic efforts and a greater sense of optimism among South Koreans for improved relations with North Korea, even though it lacked a more detailed commitment or timeline from Pyongyang to abandon nuclear weapons.61

Further diplomatic progress was made in the ensuing months. In early May 2018, North and South Korean soldiers dismantled loudspeakers that had once blared propaganda over the armistice line.62 North Korea also changed its time zone to match South Korea’s time as part of “the first practical step” toward unification.63 Furthermore, on May 24, North Korea destroyed the Punggye-ri nuclear test site, along with its surrounding tunnels and buildings, as foreign journalists watched.64 To revive a potential meeting between Kim Jong Un and Trump, Moon and Kim held a second summit inside the DMZ on May 26 to discuss implementation of their peace initiatives and ways to improve relations with the United States.65

The flurry of diplomatic activity between the two Koreas helped facilitate U.S.-North Korean diplomacy leading to the Trump-Kim summit in Singapore on June 12.66 On the military front, the two Koreas resumed ship-to-ship communications for the first time in a decade in July 201867 and restored a military communication line on the western part of the peninsula.68 In August 2018, a group of South and North Korean divided families briefly reunited at Mount Geumgang, the first family reunion since October 2015.69 Ahead of the third inter-Korean summit in September 2018, Seoul and Pyongyang opened a joint liaison office at the site of the former KIC, enabling both sides to directly communicate about issues of concern “24 hours, 365 days” with 20 people on both sides staffing the offices.70

On September 18, 2018, Moon arrived in Pyongyang for his third inter-Korean Summit.71 During his visit, Moon became the first South Korean leader to give a speech to the North Korean public during the Mass Games and called for the permanent removal of nuclear weapons and peace on the peninsula.72 Both leaders signed the Pyongyang Joint Declaration of September 2018. The two sides also adopted the “Agreement on the Implementation of the Historic Panmunjom Declaration in the Military Domain” to further expand cessation of military hostilities. They also promoted inter-Korean economic cooperation such as connecting infrastructure, including roads and railways.73 North Korea stated it would permanently dismantle the Dongchang-ri missile launch and engine testing facilities, and declared it was prepared to permanently close the nuclear production facility in Yongbyon if the United States took “reciprocal steps.”74 Both sides agreed to halt field training exercises and artillery drills in the border area to lower temperatures in the region.75 Following the breakthroughs from the third summit, Moon ratified the recent deals struck with Pyongyang, triggering immediate opposition from conservative lawmakers.76

In the spirit of engagement, a group of South Korean engineers in November 2018 traveled across the border into North Korea by train to research ways to update the North’s track and railway infrastructure to ease cross-border trade and travel.77 South Korea also promised to deliver antiviral medication and other medical supplies to North Korea as part of an effort to combat the spread of infectious diseases, such as influenza.78

The Fragility of Inter-Korean Relations
As rapidly as inter-Korean relations improved in 2018, they quickly hit an impasse and then a downturn following the abrupt end to the Trump-Kim summit in Hanoi in February 2019. Although the Moon government persisted with engagement efforts, inter-Korean relations eventually fell victim to broader geopolitical forces and external shocks, including deteriorating U.S.-North Korea relations79 and the onset of the coronavirus pandemic80 in the final months of 2019. The latter resulted in the regime closing its borders for nearly four years, further isolating the country and decreasing the number of North Korean defectors entering South Korea to a few dozen individuals (see figure 2). While Moon saw the pandemic as an opportunity for “realistic and practical” cooperation with Pyongyang,81 North Korea escalated tensions by exchanging gunfire over the DMZ82 and criticizing ongoing U.S.-ROK military drills in May 2020.83 In a sign of worsening relations in June, Pyongyang severed all communication channels with Seoul84 and later destroyed an inter-Korean joint liaison office in Kaesong, signaling frustration with the lack of progress with Moon and Trump.85

With hostilities rising, South Korea urged the North to suspend a plan to launch propaganda leaflets across the border after threatening to float 12 million leaflets as part of a major psychological campaign.86 To reciprocate, South Korea banned the launch of anti-North Korean propaganda leaflets into the North despite opposition from South Korean human rights activists and prominent defectors.87 Tensions also arose when North Korea shot and killed a South Korean Ministry of Oceans and Fisheries official who had crossed into North Korean waters.88

In 2021, Moon hoped to improve relations with Pyongyang and promised to sit down with North Korea “anytime, anywhere” to discuss cooperation.89 Moon offered COVID-19 vaccines to the North in June 2021.90 Although both countries restored cross-border hotlines in July 2021,91 North Korea stopped responding to the hotline a month later.92 The positive atmosphere in inter-Korean relations were further undermined when North Korea threatened “a serious security crisis” in retaliation for U.S.-ROK joint military drills in August 2021.93 A month later, North Korea successfully tested newly developed long-range cruise missiles.94

During the waning months of Moon’s presidency, North Korea expressed a willingness to return to the negotiating table in exchange for sanctions relief, while Moon pushed for peace and rapprochement on the peninsula.95 In October 2021, North Korea resumed communication through a cross-border military hotline with South Korea.96 However, tensions in U.S.-North Korea relations constrained Moon’s diplomatic outreach to North Korea.    

Defense, Deterrence, and Yoon Suk-yeol's Revised Unification Doctrine

Although Moon continued to pursue diplomatic efforts with North Korea until his remaining time in office in May 2022, North Korea had already begun dramatically increasing the number of missile tests earlier that year, including an ICBM test in March 2022 a few weeks after South Koreans elected conservative presidential candidate Yoon Suk-yeol to office. North Korea would go on to conduct over 90 cruise and ballistic missile tests in 2022, including several long-range ICBM tests.97

President Yoon, who took office in 2022, pursued a markedly different approach from his predecessor Moon Jae-in, emphasizing deterrence, alliance coordination with the United States and Japan, and pressure on Pyongyang rather than engagement-first diplomacy. Yoon, like his conservative predecessors, viewed inter-Korean engagement with greater skepticism, especially with tensions rising on the Korean Peninsula by the time of Moon’s departure. Partly in response to escalated North Korean provocations in 2022, Yoon resumed large-scale joint military exercises with the United States and permitted the deployment of additional U.S. strategic assets on the peninsula, such as U.S. strategic bombers and nuclear submarines.98 South Korean threat perceptions were further heightened in December 2022 when five North Korean drones entered South Korean airspace.99

Despite the absence of diplomatic engagement between the two Koreas during Yoon’s first year in office, the Yoon government unveiled its “Audacious Initiative” in August 2022 to promote inter-Korean relations.100 The Audacious Initiative promised major South Korean economic investment and aid to North Korea should the regime cease developing its nuclear program and take substantive steps toward denuclearization.101 Yoon’s engagement plan was immediately mocked by North Korea as “absurd” with the regime comparing it to President Lee Myung-bak’s “Vision 3000” proposal.102 The Kim regime also criticized Yoon for assuming that North Korea would seek denuclearization in return for economic improvement.

The Yoon government also renewed efforts to address North Korean human rights, appointing an ambassador for international cooperation on North Korean human rights in July 2022, a post that had been vacant throughout the Moon government. Furthermore, the Ministry of Unification also published its first publicly released report on North Korean human rights in March 2023,103 prompting North Korea to publish its own report criticizing South Korean human rights violations.104

Although North Korea had begun easing pandemic-induced border restrictions in North Korea in the latter half of 2023,105 inter-Korean relations had not resumed. The diplomatic momentum generated by the 2018 inter-Korean summits and subsequent U.S.-North Korea negotiations had dissipated. North Korea instead accelerated its missile development while rejecting calls to return to denuclearization talks.106

Inter-Korean relations deteriorated further in late 2023 following North Korea's successful launch of a military reconnaissance satellite. Pyongyang defended the launch as a legitimate exercise of its sovereign right to strengthen self-defense capabilities and announced plans to deploy additional reconnaissance satellites.107 Seoul viewed the launch as a violation of United Nations Security Council resolutions and responded by partially suspending the 2018 Comprehensive Military Agreement (CMA), a cornerstone confidence-building measure negotiated during the Moon administration. The CMA had established buffer zones along the Demilitarized Zone (DMZ) and maritime boundaries designed to reduce the risk of accidental military clashes. North Korea quickly retaliated by declaring the agreement null and void and restoring military activities that had previously been restricted under the accord.108

The collapse of the CMA symbolized the broader breakdown of the inter-Korean détente established in 2018. More significantly, however, the deterioration in relations coincided with a fundamental shift in North Korea's conception of the South. At the December 2023 plenary meeting of the Workers' Party of Korea, Kim Jong Un abandoned longstanding references to national reconciliation and peaceful reunification, declaring that unification under existing circumstances was no longer possible. Instead, Kim characterized South Korea as an enemy state and called for a new framework based on relations between two hostile countries.109

Renouncing unification, in January 2024, the North Korean began removing references to “peaceful reunification” and “great national unity” from websites, media reports, and monuments.110 Kim also ordered the dismantling of organizations responsible for inter-Korean affairs.111 Later that month, authorities demolished the Arch of Reunification in Pyongyang, a monument built in 2000 to symbolize hopes for eventual Korean unity. These actions represented a dramatic departure from decades of North Korean policy, which had traditionally portrayed reunification as a central national objective despite persistent political and military rivalry with the South.                                 

Against this backdrop, Yoon continued to frame unification as a long-term goal rooted in liberal democratic values and human rights. During his March 1 Independence Movement Day address in 2024, Yoon described a "free and unified Korean Peninsula" as both a national aspiration and a source of hope for North Koreans.112 He argued that stronger cooperation with the United States and Japan enhanced regional security and improved Seoul's ability to respond to North Korean threats. Later in August, Yoon used his August 15 Liberation Day address to unveil a new "freedom-based" unification doctrine that emphasized expanding freedom and opportunity for North Koreans while reaffirming Seoul's commitment to peaceful unification.

Yoon’s new vision for Korean unification existed in sharp contrast to Pyongyang’s rejection of a unified Korea. Rather than competing over alternative pathways to reunification, the two Koreas were moving toward fundamentally different understandings of their relationship. Whereas Seoul continued to define peaceful unification as a constitutional objective, Pyeongyang had rather abruptly rejected the decades-long idea of Korean reunification.

Military tensions also intensified throughout 2024. In January, North Korea fired approximately 200 artillery shells into the maritime buffer zone north of the Northern Limit Line near Yeonpyeong and Baengnyeong Islands. This prompted the South Korean government to evacuate island residents and conduct retaliatory live-fire drills in the area, launching close to 400 rounds of artillery.113

Beginning in May 2024, Pyongyang launched hundreds of balloons carrying trash and debris across the border into South Korea, describing the campaign as retaliation against anti-regime leaflets sent by North Korean defector groups. Seoul responded by fully suspending the CMA and resuming loudspeaker broadcasts along the DMZ for the first time in six years.114 The exchange revived a pattern of psychological warfare that had largely disappeared during the period of engagement under Moon. 

Additional tensions emerged in October 2024 when North Korea accused South Korea of sending drones over Pyongyang and threatened military retaliation.115 Days later, North Korea destroyed sections of road and rail infrastructure that once linked the two Koreas, further underscoring its abandonment of reconciliation.116 Kim Jong Un subsequently referred to South Korea as a "foreign country" and a "hostile country," language that reaffirmed the regime's emerging "two hostile states" doctrine.117

On December 3, 2024, President Yoon declared martial law, citing “pro-North, anti-state elements” that had infiltrated South Korean society as part of his rationale.118 Inter-Korean relations had arguably reached the lowest point in years by the time of Yoon’s impeachment at the end of 2025. While the Yoon government sought to strengthen deterrence and maintain pressure on Pyongyang, North Korea had moved beyond merely rejecting engagement and had instead redefined the political basis of inter-Korean relations between two separate states.

The Lee Administration and the Search for Peaceful Coexistence

The election of Lee Jae-myung in June 2025 marked another significant shift in South Korea's approach toward North Korea. Although Lee supported maintaining a strong alliance with the United States and preserving deterrence capabilities, his administration placed greater emphasis on reducing tensions and reopening channels of communication with Pyongyang.

One of Lee's first actions was suspending loudspeaker broadcasts along the DMZ,121  reversing one of the most visible escalatory measures adopted during the Yoon administration. The government also moved to curb anti-North Korean leaflet campaigns conducted by private activist groups, arguing that such activities unnecessarily heightened tensions and increased security risks for border communities.119 Lee presented these steps as confidence-building measures intended to create conditions conducive to dialogue.

The Lee administration provided more clarity to inter-Korean relations during his Liberation Day address in August 2025.120 Lee argued that reducing military tensions and rebuilding trust should take precedence over ideological confrontation. The president called for restoring the 2018 military agreement and declared that the two Koreas should not regard one another as enemies. In September 2025, Lee introduced the END initiative—standing for Exchange, Normalization, and Denuclearization—during his address to the United Nations General Assembly.121 The proposal sought to reduce hostility, encourage cooperation, and gradually create conditions for peace and denuclearization.

Throughout late 2025 and early 2026, Lee increasingly framed South Korea's role as that of a facilitator or "peacemaker" capable of encouraging dialogue among Washington, Pyongyang, and regional stakeholders. His administration emphasized peaceful coexistence, economic cooperation, and crisis management rather than immediate progress toward reunification.

North Korea, however, remained skeptical of Seoul's overtures. Although Pyongyang welcomed some conciliatory gestures, including the Lee government’s expressions of regret following unauthorized drone incursions into North Korean territory, it continued to reject claims that meaningful improvements in inter-Korean relations were underway. In April 2026, North Korean officials confirmed that agencies previously responsible for inter-Korean affairs had been absorbed into the Foreign Ministry, reinforcing the regime's position that relations with Seoul should be treated as state-to-state relations rather than relations within a divided nation.122 Additionally, North Korea revised its constitution in May 2026, omitting references to reunification and a shared Korean national identity while formally describing South Korea as a hostile state.123 The constitutional change further institutionalized the abandonment of reunification as a core state objective.

As of 2026, inter-Korean relations remain defined by a striking paradox. South Korea's political debate has shifted from deterrence-centered confrontation under Yoon to renewed efforts at dialogue and peaceful coexistence under Lee. Yet these policy changes have occurred at precisely the moment when North Korea has moved furthest away from the traditional framework that historically underpinned inter-Korean engagement. The result is a new era in which managing tensions, preventing military escalation, and sustaining stability may prove more achievable objectives than advancing reconciliation or reunification.124 Whether future dialogue can overcome these structural changes remains one of the central questions facing the Korean Peninsula.
 

Table 1: Inter-Korea summit meetings

Source: Andrew Yeo, South Korea’s Grand Strategy: The Rise of a Global Nation (Oxford University Press, forthcoming 2026).   

Figure 1: Inter-Korean Trade

Source: ROK Ministry of Unification

Figure 2: North Korean Defectors Entering South Korea 

Source: ROK Ministry of Unification 

Esther Im and Sung Kim contributed to earlier versions of this Issue Brief. Brookings Research Assistant Hanna Foreman contributed to the August 2023 and June 2026 updated version.