The My Lai Massacre, in which American Army soldiers killed between 300 and 500 civilians in the village of My Lai, Vietnam, clouded perceptions of the U.S. military for years.
Photograph by Ronald L. Haeberle, from the Report of the Department of the Army Review of the Preliminary Investigations into the My Lai Incident (Peers Report)

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  • On March 16, 1968, U.S. Army troops killed between 300 and 500 civilians in the My Lai hamlet, part of the larger village of Son My, Vietnam. Unfortunately, the My Lai Massacre became one of the most significant symbols of U.S. involvement in the Vietnam War.
    American soldiers claimed to be acting on orders from their commanding officers. Only one man, Second Lieutenant William Calley, a platoon leader, was convicted for the crimes at My Lai. He served three years of a life sentence before being paroled. 
    The My Lai Massacre, the Army’s initial concealment of the event, and the failure to hold any high-ranking officers accountable appalled both military and civilian critics. Many drew attention to the Nuremberg Trials, where following orders was rejected as a defense for committing war crimes. Evidence of the My Lai Massacre emerged in late 1969. Calley was sentenced in 1971 and paroled in 1974. The U.S. withdrew from Vietnam in 1975.
  • Term Part of Speech Definition Encyclopedic Entry
    accountable Adjective

    responsible or answerable for something.

    appall Verb

    to horrify, shock, or disgust.

    civilian Noun

    person who is not in the military.

    conceal Verb

    to hide.

    convict Verb

    to find someone guilty of an illegal act.

    crime Noun

    unlawful activity.

    evidence Noun

    data that can be measured, observed, examined, and analyzed to support a conclusion.

    hamlet Noun

    very small village.

    initial Adjective


    massacre Noun

    mass killing of large number of people.

    military Noun

    armed forces.

    parole Verb

    to conditionally release an inmate from prison prior to the end of their sentence.

    platoon Noun

    small military unit usually commanded by a lieutenant.

    significant Adjective

    important or impressive.

    symbol Noun

    something used to represent something else.

    troop Noun

    a soldier.

    village Noun

    small human settlement usually found in a rural setting.

    Encyclopedic Entry: village
    war crime Noun

    severe acts of violence, violating international law, committed against civilians, enemies, prisoners of war, or others during an armed conflict.