This dissertation explores different aspects related to the protection of marginal populations - here sex workers. Universally accepted norms on this protection are expressed in international conventions, translated into domestic policies, and implemented in everyday policing. The aim of this dissertation is to arrive at an answer to whether, and if so, through which mechanisms, these three steps may provide protection. My research is situated at the intersection of the anti-trafficking norm, prostitution policy, and policing practices for the protection of people in the sex industry. The three research chapters look at who gets to speak and who is silenced in international norm-making, analyze apparent binaries of protection and repression, and theorize which policing practices best protect those at the margins. I set the stage through a critical reading of the anti-trafficking norm from the early 20th century until today. I analyze how local police forces translate the Geneva prostitution law into everyday practices by drawing on my fieldwork in Geneva (November 2015 to November 2017). Finally, I combine these findings with others from another field study in San Francisco, United States (April to October 2018) and from previous studies to code a simulation on the effects of different prostitution policy types on sex workers' willingness to report an assault.