Today the Supreme Court hears oral arguments in what the Becket Fund for Religious Liberty is calling “the most important religious liberty case in twenty years.”

Hosanna-Tabor Evangelical Lutheran Church and School v. EEOC involves a lawsuit between a church and one of its teachers who was required to teach religion, lead prayer, and fulfill other important religious duties at the school operated by the church. The church sought to resolve a dispute with the teacher using an internal resolution procedure informed by the church’s religious beliefs. The teacher refused to abide by the church’s teachings on dispute resolution and, instead, filed a lawsuit with the Equal Employment Opportunity Commission (EEOC). Both the EEOC and the teacher then sued the church.

According to the Becket Fund, which represents the church, the issue in this case is “the extent to which the government can control a church’s selection of religious leaders.” The teacher, who originally wanted the government to force the church to reinstate her as a teacher, seeks an award of monetary damages. The church claims that religious freedom means it should be permitted to select the teachers who will instill the faith in the next generation of students and that it should not have to pay monetary damages to someone it has determined should not fulfill these duties.

Resolution of the issue turns upon how the Supreme Court will apply a legal doctrine known as the “ministerial exception.” Even non-lawyers can easily understand the Becket Fund’s succinct explanation of the doctrine:

[F]or forty years, the lower courts have uniformly held that there is something called a “ministerial exception” to employment laws. The ministerial exception is a constitutional rule that says when someone performs important religious functions—like a pastor, priest, or rabbi—that person cannot sue the church and force it to reinstate him as a minister. Churches have freedom to pick who their ministers are, and the government cannot interfere in that relationship.

The difficult question is how far down the hierarchy the ministerial exception extends. Priests and rabbis are obviously covered; secretaries and janitors are not. What about all the positions in between—like choir directors, school teachers, and leaders of religious charities?

That is where the new Supreme Court case comes in. The employee in Hosanna-Tabor Evangelical Lutheran Church and School v. EEOC is not a rabbi, and she is not a janitor.

She is a fourth-grade teacher at an elementary school. She has some secular duties and some religious duties. She teaches typical secular subjects, like reading, writing, and arithmetic.

But she also teaches daily religion classes, serves as a commissioned minister within the Church, and regularly leads students in prayer and worship.

The question is whether a lawsuit by this sort of employee is barred by the ministerial exception.

In addition to the narrow legal issue, the case raises broader questions. Will government choose individuals who teach religion? Or will churches have the freedom to choose for themselves who teaches their faith to the next generation?

How the Supreme Court answers those questions “will have a profound impact on every religious group in the country.”