There has been a recent trend in several states to consider and adopt state constitutional amendments or statutes that attempt to prohibit state courts from considering or applying foreign law in their judicial decisions. The first effort of this kind occurred in Oklahoma in 2010, and similar laws have been enacted in several other states in ensuing years. One aim of these provisions (which was made explicit in Oklahoma) is to prevent state courts from incorporating “Sharia” (Muslin law) into judicial decisions. Another aim is to assert a broad principle of American exceptionalism that supports exclusion of all foreign law regardless of its source. This article addresses the questions whether such a limitation on state judicial decisions is constitutional, and if so whether it represents a desirable restriction on the judicial process. In Awad v. Ziriax, Oklahoma’s attempt to prevent judicial use of foreign and international law was struck down as a violation of the First Amendment’s Establishment Clause. This result was justified by the law’s explicit attempt to single out Sharia for specific legal …