This paper explores the persistent significance of the My Lai massacre. It also analyzes far and immediate causes of the massacre: the unique but atrocious American way of war in Vietnam, the National Liberation Front’s ‘people’s war,’ and the psychological disorientation of the American soldiers. The My Lai massacre led the American leaders to step back from the American ‘quagmire,’ radically shifting the fog of the war. This shift of policy led by Johnson and Nixon administrations ultimately fails, however, and America loses the war, making American exceptionalism seriously dismantled. America’s uniquely resilient collective narrative which Richard Slotkin calls the ‘regeneration through violence’ finally survives, however, and, though seriously wounded, American empire revives its collective illusion as a special nation with a manifest mission. The My Lai massacre supplied America a rare opportunity to reroute its imperial trajectory, but it unfortunately keeps imagining itself as an exceptional nation, as we can see even now around the world after its engagements in Vietnam more than 50 years ago.