We need to understand better the political barriers to prison-based harm reduction programs. In this paper, I examine the situation in the Correctional Service of Canada (CSC), a federal prison agency with a zero-tolerance drug policy and general opposition to prison needle and syringe programs (PNSPs) and safer tattooing initiatives.This study draws on 16 interviews with former CSC senior officials, former frontline staff, and external stakeholders; CSC policy and practice documents; and testimony from a House of Commons Standing Committee public study. Thematic coding and comparison of texts were used to examine emergent themes of interest.Four interrelated issues were central for understanding the political barriers: a narrower definition of harm reduction used in corrections, both in principle and practice; the Conservative government's tough-on-crime agenda; strong union opposition; and stakeholder perceptions that political constraints will likely persist, including the view that litigation may offer the only way to introduce PNSPs.The system is at an impasse and key questions remain about the importability of harm reduction services into federal prisons. Despite a highly challenging policy environment, moving forward will demand asking new, critical questions and devising more strategic ways of entering the political-operational dialogue that opposes evidence-based programs.