South Korea 2025 Presidential Election

About 297 personnel were deployed within ten minutes of the declaration on the night of 3 December 2024: roughly 10 to the NEC headquarters in Gwacheon, 130 to the NEC training centre in Suwon and 47 to the National Election Survey Deliberation Commission in Seoul. The Constitutional Court found that the deployed troops controlled access, seized staff mobile phones and photographed the IT systems, and that these searches and seizures without a warrant violated the warrant requirement and infringed the independence of the commission as a constitutional body.

In a televised address on 12 December 2024 Yoon Suk Yeol said that 'the NEC's capability of managing elections is questionable' and that he 'was wondering if voters would trust the election results when its cybersecurity is so vulnerable to cyberattacks and hacking', citing the National Intelligence Service's 2023 checkup as his basis for sending troops to commission premises. The Constitutional Court recorded his contention that martial law was declared to dispel suspicions of electoral fraud and held that simply having such suspicions did not mean that a serious crisis had actually occurred, noting that the commission had already taken security measures before the election.

The Constitutional Court unanimously removed Yoon Suk Yeol from office on 4 April 2025, holding that the constitutional and statutory conditions for emergency martial law were not met and that simply having suspicions of electoral fraud did not mean a serious crisis had occurred. On 19 February 2026 the Seoul Central District Court convicted him of leading an insurrection and sentenced him to life imprisonment, holding that his justification 'confuses motive with purpose' and that 'a desire to address a perceived national crisis may explain intent, but does not justify unconstitutional means'. That criminal judgment was delivered at first instance and is not final.

The National Intelligence Service reported that in April 2021 the North Korean group Kimsuky used malicious code against an NEC computer and stole classified documents. Its joint inspection with the Korea Internet and Security Agency between July and September 2023 found weaknesses in the voter register management, ballot counting and early voting systems and said North Korea could breach the network at any time. The commission accepted that one programme had a password management deficiency and said most identified vulnerabilities were remedied and re-inspected with NIS participation before the April 2024 National Assembly election.

The Supreme Court, the only court competent to hear a challenge to a presidential or National Assembly election, gave judgment on 28 July 2022 in cases 2020Su30 and 2020Su5028, the lead suits seeking annulment of results of the 15 April 2020 National Assembly election, and dismissed the plaintiffs' claims; the press release records the cases as those in which recount allegations were examined. Fact-checking of the whole set of suits found that all 126 were dismissed and that the irregularly printed 'cabbage leaf' ballots offered as evidence were held by the court to be minor mistakes and simple mechanical errors that could not be evidence of fraud changing an outcome.

Claims circulating after the martial law declaration held that United States and Korean forces had arrested Chinese hackers at a National Election Commission training facility. United States Forces Korea issued a statement saying that the descriptions of and claims about the United States military in those reports were 'entirely false'. The record of the training centre for that night accounts for the people staying there as 96 in total, 88 public officials on promotion and posting courses and eight external auditors.

The central quantitative claim of the fraud narrative is that early voters and election-day voters split too regularly between the parties to be genuine. Fact-checkers, citing a former statistics official, point out that early and election-day voters are different populations rather than random samples of a single population, because participation rates in early voting differed by candidate preference, so their shares are not expected to match. Arguments of this kind were among the grounds raised in the nullification suits over the 2020 National Assembly election, and the Supreme Court dismissed those claims.

The National Intelligence Service said simulated attacks could manipulate voter registrations and ballot counts, mark early voters as not having participated, and print ballots without authorisation. The National Election Commission replied that even if hacking the system is technically possible that does not necessarily lead to a rigged election, because manipulating an outcome would be almost impossible without organised assistance from insiders, and it added in December 2024 that the tests had been run with its security systems partially disabled and that most identified vulnerabilities had been remedied and re-inspected with NIS participation before the April 2024 National Assembly election. No official body, court or inspection has found that any Korean election result was changed.