Reformers have traditionally assumed that agencies can combat corruption through controls such as tighter oversight, increased regulation, internal audits, reorganizations, and performance accountability mechanisms. But this case study of the New York City school custodial system shows how a corrupt agency can derail these devices. New York City's $500,000,000 custodial system, responsible for maintaining its 1,200 schools, has been unleashing scandals since the 1920s despite decades of regulations, multiple reorganizations, and layers of oversight. Its history shows that a deviant culture—a management “captured” by special interests—and an infrastructure enmeshed in abusive policies will resist controls, no matter how well-crafted. True reform requires tackling institutionalized corruption through strategies like overhauling management, eradicating special interests, and aggressively punishing misconduct.