Commercial sexual exploitation and human trafficking are undeniably harmful, and are sustained entirely by the revenue provided by consumers. Prevention of these crimes cannot be achieved without addressing their root cause, and thousands of local law enforcement agencies throughout the U.S. have recognized this fact and have employed tactics targeting consumer-level demand. Yet demand remains the most neglected segment of these illicit markets, particularly at the federal level. This presentation illustrates disconnects in evidence, policy, and practice across the Nation, and examines the role of the decriminalization movement in blocking evidence-based practices that would prevent victimization and reduce harm. We focus specifically on one of the most influential assertions made by decriminalization advocates: removing all legal restrictions on prostitution would produce massive reductions in HIV infection rates. A thorough examination of the research producing that finding found it to be significantly flawed, and the assertion about prevention to be unsupported by evidence. We conclude by discussing the role of these findings in suppressing efforts to prevent sexual exploitation and trafficking.