This article expands the study of the politics of international criminal justice, restoring the crucial but overlooked case of Bangladesh, today the largest population confronting the aftermath of genocide. Bangladesh is one of the most important cases where the prosecution of war criminals was foiled, resulting in a disturbing impunity for one of the bloodiest incidents of the Cold War. Using unexplored declassified Indian government documents from archives in Delhi, this article uses detailed process-tracing to reveal for the first time why India and Bangladesh abandoned their plans to put accused Pakistani war criminals on trial after the 1971 war between India and Pakistan. In the face of Pakistani defiance, the Indian and Bangladeshi governments reluctantly bargained away justice in order to pursue their national security, with peacemaking with Pakistan proving more important than war crimes trials. This episode furthers the general understanding of both the causes and results of impunity for mass atrocities, while extending the study of international justice into Asia. Bangladesh’s tragic experience shows the primacy of international security, while also tentatively suggesting that even when amnesty is necessary for peacemaking, it can leave a toxic legacy for future politics.