While political science scholarship recognizes that the effectiveness of international law often rests on its domestic implementation, relatively little attention has been given to the national legal rules that govern this process. These rules, which govern matters such as treaty-making, how treaties and custom are received and interpreted, and their status vis-à-vis other sources of domestic law, differ substantially across countries and over time. In this paper, we examine these rules and their role in shaping the state’s engagement with international law by allocating authority among political actors and institutions. We incorporate empirical insights from an original dataset, which captures in detail the domestic rules that govern the creation, implementation and interpretation of international law for 101 countries for the period 1815-2013. We contrast our data with existing proxies used in the literature, such as legal traditions, explicit constitutional provisions, and the monist-dualist classification, and show that our dataset offers more fine-grained and precise information on international law’s place in national legal orders. 

Pierre-Hugues Verdier & Mila Versteeg, Modes of Domestic Incorporation of International Law, in Research Handbook on the Politics of International Law, Edward Elgar, 149–175 (2017).