When can a priest not be considered a priest? It depends on what his “primary” duties are. That is a question answered by a federal appellate court and one that has potentially wide implications for religious employers.

Indeed, the question is significant enough that the Supreme Court has been asked to weigh in on the issue.

The facts of the case, called Hosanna-Tabor Evangelical Lutheran Church and School v. Equal Employment Opportunity Commission, are relatively straight forward. The federal EEOC brought a case against Hosanna-Tabor, an evangelical Lutheran church and affiliated school, for firing one of its teachers. The EEOC claimed that the firing violated the Americans With Disabilities Act (ADA) because the teacher suffered from a medical condition.

The church argued that the teacher was not simply an employee, or what the church called “lay teacher.” Rather, she was one of a category of “called” teachers. She had received a commission as a minister in the church, whose responsibilities included both teaching secular subjects and engaging in religious activities. Therefore, the ADA did not apply to the teacher’s termination because of a legal doctrine known as the “ministerial exception.”

The lower federal court found for Hosanna-Tabor, but an appellate court reversed and found for the EEOC. That court ruled that the employee did not fit within the ministerial exception, and so, therefore, the requirements of the ADA applied to the church’s employment relationship with the teacher.

The ministerial exception is a doctrine that is meant to protect religious institutions from too much interference from secular authorities. In 1972, one of the first courts to adopt the doctrine stated, “The relationship between an organized church and its ministers is its lifeblood”; allowing the state to interfere in that relationship — effectively allowing judges and juries to pick ministers — would produce “the very opposite of that separation of church and state contemplated by the First Amendment.”

Yet the Hosanna-Tabor court took the position that as long as the teacher’s duties were “primarily” secular, the exception did not apply. To come to that conclusion, the court tried to determine whether the teacher was a minister by examining the teacher’s responsibilities under the “primary duties” test.

Under this test, “an employee is considered a minister if the employee’s primary duties consist of teaching, spreading the faith, church governance, supervision of a religious order or supervision or participation in religious ritual and worship.” The court found that the teacher was not subject to the ministerial exception because “she spent the overwhelming majority of her day teaching secular subjects using secular textbooks.”

Further, the court did not see any substantive difference between the duties of the law and “called” teachers.

The case may have troubling consequences, especially as there are a number of federal courts around the country that have adopted the “primary duties” test, which other federal courts have denounced as “rigid” or “arbitrary.”

The problem with the test is obvious: The courts should not be determining who is primarily a “minister” and who is not. Such a test would require the court to distinguish between “secular” and “religious” activities. This is difficult enough.

The task is made more difficult when the person, like the teacher at Hosanna-Tabor, is called to serve as a teacher in a formal manner. The court dismissed this distinction, finding that “the title of commissioned minister does not transform the primary duties of these called teachers from secular to religious in nature.”

There goes the concept of a vocation recognized by a community to inhere in the person’s actions and very being. A vocation to religious life and being called “Father” is not the same as having the title “vice president.”

Or consider the case of a lay brother in a religious community: not ordained, doing perhaps physical — not “religious” — tasks, yet one whose calling is explicitly religious. Indeed, the court was reduced to counting the number of times the teacher brought “religion” into her teaching of religious subjects.

Enforcing legislation like the ADA will have another harmful effect: It will place even greater burdens on small congregations and religious schools that do not have the infrastructure to withstand costly legal battles over whether they can convince a court that someone qualifies as a “minister.”

This decision is potentially so important that lawyers for Hosanna-Tabor, including the Becket Fund for Religious Liberty, which is one of the stalwarts in protecting religious liberty worldwide, have recently petitioned the Supreme Court to hear the case and clarify that courts should not determine how a religious institution controls its internal affairs.

Gerald J. Russello is a fellow of the Chesterton Institute at Seton Hall University.