Over the past year, several state legislatures have proposed measures that would restrict the consideration of religious law in domestic courts. In November 2010, voters in Oklahoma definitively approved a state constitutional amendment that would prohibit the use or application of Islamic law (sharia) in state courts, which led to a lawsuit challenging the constitutionality of the amendment under the First Amendment of the U.S. Constitution. This report will discuss various legal issues related to the role of religious law in U.S. courts. Finally, the report explains the role that foreign law generally may have within the U.S. legal system and potential unintended consequences that may arise from restrictions on the consideration of religious and foreign laws. Potential limitations on particular religious beliefs may run afoul of the Free Exercise Clause if they impose restrictions on the ability of individuals to practice their religious faith. Establishment of Religion

The Establishment Clause prohibits the government from taking actions that would benefit one religion or religion generally. The Court noted its long-standing principle in Establishment Clause cases "that the First Amendment forbids an official purpose to disapprove of a particular religion...." However, the Court explained that Establishment Clause jurisprudence typically involved cases that allegedly benefited some religion and that challenges to laws that allegedly disfavor religion are more appropriately addressed by the Free Exercise Clause, as a government action that infringes upon the exercise of the targeted religion. Others propose broader bans on religious law or foreign law generally. Consideration of foreign and international law by domestic courts has been a controversial matter for various reasons in recent years. Constitutional Amendment Banning Sharia and Reference to Other State Laws That Apply Sharia (Wyoming)
In January 2011, Wyoming proposed an amendment to its state constitution that would bar courts from considering international law, sharia law, or the laws of other states if those states' laws include sharia law:
When exercising their judicial authority the courts of this state shall uphold and adhere to the law as provided in the constitution of the United States, the Wyoming constitution, the United States Code and federal regulations promulgated pursuant thereto, laws of this state, established common law as specified by legislative enactment, and if necessary the law of another state of the United States provided the law of the other state does not include Sharia law.
Controversy has surrounded attempts by several state legislatures to limit the consideration of Islamic religious law (commonly referred to as sharia) or religious law generally, in domestic courts. In one of the most publicized examples, Oklahoma voters definitively approved a state constitutional amendment that prohibited state courts from considering "sharia law," but the amendment has not taken effect pending the outcome of a lawsuit challenging its constitutionality. Other states have introduced variations of this limitation, with some generally prohibiting the use of religious principles in domestic courts.
Critics have questioned the constitutionality of several recently proposed or enacted measures under the religion clauses of the First Amendment of the U.S. Constitution. The Establishment Clause prohibits the government from establishing an official religion or showing preference among religions or between religion and non-religion. The Free Exercise Clause prohibits the government from burdening an individual's ability to exercise his or her religious beliefs if the burden does not arise from neutral law of general applicability but instead infringes upon a particular set of beliefs. Any bill that would specifically ban sharia may be challenged as a disapproval of Islam in violation of the Establishment Clause or as an infringement on the ability of Muslims to freely exercise their beliefs under the Free Exercise Clause. Broader proposals that address religion generally would not necessarily comport with the First Amendment either, however.
This report discusses proposals to limit the consideration by domestic courts of religious principles in general, and Islamic law in particular. It explains the role that religious law and beliefs may play in U.S. courts and analyzes the constitutional protections for religion in the First Amendment. Finally, the report also addresses the role of foreign and international law generally in U.S. courts and potential unintended consequences of restrictions on the consideration of religious or foreign law.