The past few decades have seen the proliferation of new laws criminalizing certain transnational activities, from money laundering to corruption; from insider trading to trafficking in weapons and drugs. Human trafficking is one example. We argue criminalization of trafficking in persons has diffused in large part because of the way the issue has been framed: primarily as a problem of organized crime rather than predominantly an egregious human rights abuse. Framing human trafficking as an organized crime practice empowers states to confront cross border human movements viewed as potentially threatening. We show that the diffusion of criminalization is explained by road networks that reflect potential vulnerabilities to the diversion of transnational crime. We interpret our results as evidence of the importance of context and issue framing, which in turn affects perceptions of vulnerability to neighbors’ policy choices. In doing so, we unify diffusion studies of liberalization with the spread of prohibition regimes to explain the globalization of aspects of criminal law.