This dissertation examines the role of discourse and domestic structure in the diffusion of norms and the conditions under which the policy recommendations of transnational advocates transplant to the domestic law of a target state. In particular, it examines contemporary episodes of transnational pressure that either succeeded or failed to bring a country's legal commitments more closely in line with the constitutive and regulative norms of international society. This research challenges mainstream international relations literature on the subject, which relies on either a rationalist logic of norm diffusion or the constructivist logic of norm localization. In addition, this work expands beyond sociological institutionalist literature that leaves largely unexamined the agency of domestic actors in the promotion and resistance of normative change. Instead, I explore the communicative interactions among transnational actors, domestic reformers, and domestic reactionaries (so-called "legal nationalist rebels") to show that normative change is determined not only by coercion or emulation, but also by the discursive practices of these actors. Through a study of legal development in a civil law state-China-and common law state-South Africa-this dissertation demonstrates that transnational discourse can both create and block channels for the diffusion of ideas about best practices, legitimacy, and perceptions of policy problems. More specifically, it addresses the problematic conflation between discourse and norms by incorporating insights from communication theory and social psychology research. By speaking interchangeably of "grafting onto a norm" and "appealing to resonant discourses," norm localization theorists often ignore the observation that the more strongly held a belief or deeply engrained a practice, the less an actor can articulate his or her reasons for holding that belief or engaging in that practice. It follows that entrenched beliefs and practices are especially vulnerable to discursive challenge, whereas contested practices are more likely to have already generated an active discourse that can be readily employed in their defense. The vulnerability of deeply entrenched norms thus suggests that transnational advocates and their domestic counterparts may not be as bound by "local values," as some scholars have suggested, and are instead capable of affecting legal rules previously thought too entrenched for reform.