The First Amendment to the Constitution does not impose, as some believe, “a wall of separation between church and state.” That phrase comes from a letter by Thomas Jefferson in 1802 to Connecticut Baptists, cited approvingly by Supreme Court decisions in 1878 and 1947.

The First Amendment begins, “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; . . . .“ In 1940, the Supreme Court, by invalidating a law requiring solicitors of a religion to obtain a license, ruled unanimously in Cantwell v. Connecticut that the free exercise clause was applied to the states by the 14th Amendment.

Other decisions followed in which the Court ruled that citizens could be exempt from otherwise unobjectionable laws because of their right to freely exercise their religious beliefs: A Seventh Day Adventist could collect unemployment benefits even though unwilling to work on her Sabbath (1963); Amish parents could refuse to send their children to school beyond the eighth grade (1972).

In 1990, the Court ruled otherwise in a case involving criminal laws, upholding Oregon’s refusal to provide unemployment benefits to Indians who used peyote as a sacrament. In response, Congress in 1993 passed by near-unanimous margins the Religious Freedom Restoration Act. It required allowing free exercise of religion contrary to an otherwise valid law, unless it was a narrowly tailored regulation serving a compelling government interest.

It was under that law that the family-owned business Hobby Lobby and the Little Sisters of the Poor challenged the regulation issued under the Affordable Care Act requiring health insurance to cover abortion. In Hobby Lobby v. Burwell in 2014, a 5-4 majority of the Supreme Court ruled that the abortion mandate was not the method “least restrictive” of the free exercise of religion by which the government could have sought its goal.

In 2016, the Court unanimously sent the case back to lower courts to give both sides “an opportunity to arrive at an approach going forward that will accommodate the challengers’ religious exercise” while ensuring that their health plans will give equal coverage to contraceptives.

The Court ruled against Blaine Amendments, by a 7-2 majority, in June 2017. Missouri had barred churches from receiving state funds available to other nonprofit organizations, a restriction the majority said infringed on free exercise.