The conflict developed out of the political and social upheaval that followed Korea’s liberation from Japanese colonial rule in 1945. Tensions intensified under the U.S. Army Military Government in Korea (USAMGIK), amid police crackdowns, torture, and terrorism by right-wing groups such as the Northwest Youth League. An armed uprising began on Jeju Island on April 3, 1948. The uprising opposed, among other things, the May 10, 1948 election for South Korea’s new Constitutional Assembly and the establishment of a separate government in the southern half of the peninsula. On Jeju, the election failed in two of the island’s three electoral districts, where voter turnout fell below the level required for valid results. The failure was followed by an increasingly severe campaign of suppression, culminating in the scorched-earth operations of late 1948 and early 1949.

A U.S. military intelligence report cited by Heo Ho-joon estimated that 14,000 to 15,000 Jeju residents were killed in 1948 alone, at least 80 percent of them by the security forces. Heo describes Jeju during the scorched-earth campaign as an “island of death—a killing field” and argues that the slaughter can be understood in genocidal terms. The author traces American involvement from the USAMGIK period into the years after the establishment of the Republic of Korea, when U.S. military advisers and diplomatic officials continued to exercise significant influence over the suppression. Drawing on American and Korean military and government records, contemporary reports, archival materials, and interviews with former U.S. military advisers, he reconstructs what American authorities knew and the forms their participation in the suppression took.

Heo identifies the right-wing Syngman Rhee government and its security forces as bearing primary responsibility for the massacres, while documenting the knowledge, influence, and direct and indirect involvement of American authorities. The book is the product of more than thirty years of research and reporting by Heo Ho-joon on the Jeju April 3 Incident, beginning with his work as a Hankyoreh reporter based on Jeju-do in 1989.