The creation of state practice through national court decisions can be seen as a way for national courts to play a role in transnational judicial dialogue.  That is, cross-pollination between national court decisions in different countries could harmonize the law in those countries, creating consistent state practice and, hence, customary international law.  This proposition, however, raises doctrinal and practical questions. Do all national court

decisions that deal with customary international law qualify?  Are there practical limitations to the use of national court decisions as evidence of state practice and customary law? This article examines the status of national court decisions as state practice for purposes of the formation of customary international law.  It looks at the role of national courts in both “norm creation” and “norm interpretation.” In terms of norm creation, the major doctrinal or theoretical approaches to customary international law are likely to view at least some national court decisions as state practice.  Decisions of United States courts related to customary law, therefore, may be viewed by other countries as United States practice. As for norm interpretation, consideration of foreign court decisions as state practice faces several difficulties: inconsistencies between courts and practice of other government branches, reliance by courts on national law versions of international law, difficulties in understanding foreign legal systems, and lack of judicial training in conducting surveys of foreign judicial practice. These problems suggest caution in the use of foreign court decisions in determining state practice, dampening the prospects of their use in transnational judicial dialogue.