The Religious Freedom Restoration Act of 1993, Pub. L. No. 103-141, 107 Stat. 1488 (November 16, 1993), codified at 42 U.S.C. § 2000bb through 42 U.S.C. § 2000bb-4 (also known as RFRA), is a 1993 United States federal law aimed at preventing laws that substantially burden a person's free exercise of their religion. The bill was introduced by Howard McKeon of California and Dean Gallo of New Jersey on March 11, 1993. It was held unconstitutional as applied to the states in the City of Boerne v. Flores decision in 1997, which ruled that the RFRA is not a proper exercise of Congress's enforcement power. But it continues to be applied to the federal government, for instance in Gonzales v. O Centro Espirita Beneficente Uniao do Vegetal, because Congress has broad authority to carve out exemptions from federal laws and regulations that it itself has authorized.

This law reinstated the Sherbert Test, which was set forth by Sherbert v. Verner, and Wisconsin v. Yoder, mandating that strict scrutiny be used when determining if the Free Exercise Clause of the First Amendment to the United States Constitution, guaranteeing religious freedom, has been violated. In the Religious Freedom Restoration Act, Congress states in its findings that a religiously neutral law can burden a religion just as much as one that was intended to interfere with religion; therefore the Act states that the “Government shall not substantially burden a person’s exercise of religion even if the burden results from a rule of general applicability.” The law provided an exception if two conditions are both met. First, if the burden is necessary for the “furtherance of a compelling government interest.” Under strict scrutiny, a government interest is compelling when it is more than routine and does more than simply improve government efficiency. A compelling interest relates directly with core constitutional issues. The second condition is that the rule must be the least restrictive way in which to further the government interest. The law, in conjunction with President Bill Clinton's Executive Order in 1996, provided more security for sacred sites for Native American religious rites.

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In the case of Adams v. Commissioner, the United States Tax Court rejected the argument of Priscilla M. Lippincott Adams, who was a devout Quaker. She tried to argue that under the Religious Freedom Restoration Act of 1993, she was exempt from federal income taxes. The U.S. Tax Court rejected her argument and ruled that she was not exempt. The Court stated: "...while petitioner's religious beliefs are substantially burdened by payment of taxes that fund military expenditures, the Supreme Court has established that uniform, mandatory participation in the Federal income tax system, irrespective of religious belief, is a compelling governmental interest."[15] In the case of Miller v. Commissioner, the taxpayers objected to the use of social security numbers, arguing that such numbers related to the "mark of the beast" from the Bible. In its decision, the U.S. Court discussed the applicability of the Religious Freedom Restoration Act of 1993, but ruled against the taxpayers.