The justices clarified the class of employees who are barred from suing their religious employers, in a case examining when a religious institution is shielded from anti-discrimination law.

It's the latest case to come before the court exploring the relationship between church and state, and represented a win for conservatives arguing in favor of religious freedom. The ruling came on the same day the court sided with the Trump administration and blocked a requirement for employers to cover contraceptives under the Affordable Care Act.

Seven years ago, the court recognized a "ministerial exception" for the first time, holding that under the First Amendment the government could not interfere with a church's employment decisions. The justices said that the teacher in that case could be considered a "minister."

"Requiring a church to accept or retain an unwanted minister, or punishing a church for failing to do so," Chief Justice John Roberts wrote for a unanimous court at the time, deprives the church "of control over the election of those who will personify its beliefs," and "a religious group's right to shape its own faith and mission through its appointments."

The case concerned the scope of that decision and whether it encompassed teachers who said they have limited religious duties.

Agnes Deirdre Morrissey-Berru sought to sue Our Lady of Guadalupe School for employment discrimination. She worked as a substitute teacher for the school in California, and later as a full-time fifth- and sixth-grade teacher. One of the courses she taught daily was religion, and she was required to be Catholic and lead a daily prayer.

But during the 2014-2015 school year, she was moved to a part-time position and the next year the school did not renew her contract. The school said the decision was made because of her teaching performance, but Morrissey-Berru said the school discriminated against her based on her age.

Kristen Biel, who has since passed away, was employed at St. James School as a fifth-grade teacher, including teaching religion a few days a week, from 2013-2014. At the end of the year she informed the principal that she had breast cancer and needed time off. A few weeks later, she was told her teaching contract would not be renewed due to her "classroom management." She sought to sue her school under the Americans with Disabilities Act. Biel's husband is now representing her estate.

In court, lawyers for the teachers told the justices that they were lay teachers and if the schools were to prevail "it would strip more than 300,000 lay teachers in religious schools across the country of basic employment law protections."

"It would blow a hole in our nation's civil rights laws and our employment laws in general to say that categorical immunity applies and so schools can pay people different amounts, use race, sex, other private characteristics even when they have nothing to do with the religion and religious values at stake," argued Jeffrey L. Fisher, one of the law