‘Tis the season for “holiday” parties in public school classrooms and “holiday” concerts in the auditoriums. These celebrations may give a nod to Hanukkah and Kwanzaa, but, particularly in schools where most teachers and kids are Christian, they sometimes end up looking a lot like celebrations of the birth of Christ.

How can schools figure out where the line is between letting students and teachers express their beliefs and violating the First Amendment’s Establishment Clause? Writing for The Phi Delta Kappan in 2003, Joanne E. Marshall, an education and policy scholar, offered some advice in the form of a short quiz.

Marshall asks school officials to consider twelve scenarios. Imagine these, for example:

• A Jewish teacher lectures on the Five Pillars of Islam.
• During a class discussion on the Middle East, students claim the U.S. should “protect the Holy Land because America is a Christian nation.”
• A student wears a T-shirt to class reading “Hell will keep you warm” on the front and “Are you saved?” on the back.
• A student gives a speech about the Dalai Lama’s influence on her life, discussing Buddhist teachings.
• A teacher tells his class that he is fasting for Ramadan.
• After polling the class and finding that all of the students identify themselves as Christian, a teacher holds a party and plays Christmas music.

Marshall writes that the key question in each case is whether the school as an institution is encouraging (or inhibiting) the exercise of religious expression. So, lecturing on the tenets of Islam is fine—and, in fact, an important element of a humanities or social sciences education. But the teacher can’t advocate for or attack the Muslim faith.

Since students aren’t official representatives of the government, they have much more leeway than teachers in expressing their own faith. In that discussion of the Middle East, students can make a religiously motivated argument. But a teacher moderating the discussion should point out that U.S. Constitution prevents the country from being an explicitly Christian nation.

It’s also acceptable for the student to wear that T-shirt, as long as it’s subjected to the same school dress code as any other piece of clothing. When it comes to the speech about the Dalai Lama, Marshall writes that it’s fine as long as the student doesn’t use the “captive audience” provided by the class to harass students who don’t share her beliefs.

What about the teacher talking about his fast? He probably shouldn’t bring the subject up out of nowhere, Marshall writes. That could look like endorsing a particular religious activity in his official capacity as a government employee and authority figure. But if students ask why he’s not eating lunch, it would be appropriate to explain the Ramadan tradition without going into personal detail about his beliefs.

Finally, according to Marshall, playing Christmas music at the classroom party should definitely not be permitted. Religious celebrations—even ones that are largely secular—ought not to be official school activities. That’s worth remembering this “holiday” season.