Kent Greenawalt discusses the permissibility, scope, and rationale for law to provide exemptions to protect religious and nonreligious conscience in the United States. It may be difficult for the law to determine which sentiments amount to conscience given differences in individuals’ perception and the strength of their convictions. Even the notion of a religious conscience is complex. Religious citizens’ conclusions about matters of interest to religion may proceed from both religion and reason, or only from reason. It is not clear what should count as religious, given differences between denominations and their ideas over time. There are a host of factors bearing on the permissibility and wisdom of granting exemptions, determining their scope, and deciding whether to extend protections to nonreligious conscience. A first principle is the importance of respect for others and for tolerance in a democracy. These questions about exemptions can be considered by looking closely at contested issues, like objection to the military draft, laws governing the manner of killing animals, ingestion of banned substances, abortion, and objection to insurance mandates concerning contraceptives.