The failure of the international community to act on the legal and moral imperative to stop, punish, and prevent genocide and other mass killings has led to the establishment of genocidal regimes that institutionalize genocide as a tactic of repression and power consolidation. One such repeat offender regime was the New Order government of Indonesia, which committed mass killings of known and alleged communists throughout Indonesia in 1965–1966 and later carried out a genocidal, colonial occupation of East Timor. I demonstrate parallels between the actors, tactics, and discourse of the communist killings and the Timorese Genocide. The failures of domestic resistance and international pressure to punish the New Order after 1966 allowed génocidaires to retain power and reinforced their belief in the acceptability and effectiveness of genocidal tactics. The Indonesian case illustrates the necessity of punishment for genocide to preclude a culture of impunity that encourages both previous and new offenders.