I've represented public school students for 25 years in disputes arising over their constitutional rights and liberties. In these circumstances, the teacher committed an error in judgment, an error likely based in ignorance of the law that governs these issues, an error that was likely made in a kind of good faith.
First things first.
The First Amendment, which is often described as erecting a wall of separation between church and state, limits government actions, not those of private individuals. This means, for example, that Mayor McCheese (or any other government official) may not require the Hamburgler or Ronald McDonald to declare belief in a Deity (or, for that matter, to DENY such belief). It does not mean, however, that Dad or Mom violate the Constitution by requiring their daughter or son to attend church.
The essence of the rule is the distinction between public and private actors. The specific language of the First Amendment makes this clear: "CONGRESS SHALL MAKE NO LAW...." Consequently, a student is LEGALLY INCAPABLE OF VIOLATING THE FIRST AMENDMENT by engaging in religious activities in public schools or elsewhere. That conclusion is evidenced by a decision of the Supreme Court in Westside Community Schools v. Mergens.
That case, from 1990, involved a federal statute, the Equal Access Act. Congress enacted he Equal Access Act because some public schools around the Nation denied students the right to form student initiated, student led religious clubs on campus. Schools that did so often asserted that they were obliged to exclude student religious activities from campus to avoid violating "the wall of separation between church and state." The Supreme Court concluded that the Act was, itself, constitutional despite claims that it violated the separation of church and state. The Court went to some pains in its opinion to explain that religious activities initiated and led by students not only DO NOT violate the Constitution, such activities are PROTECTED BY both the Free Exercise of Religion Clause and the Freedom of Speech Clause.
So how could a situation like this one occur?
As I said, this appears to be a case of teacher ignorance. It could be malicious, but at this point I lack information to assume an anti-religious bias by the teacher. Instead, this teacher is likely no different from the thousands and thousands of others for whom the First Amendment is a distant novelty.
I am linking here to a survey performed by the Freedom Forum that demonstrates how real this problem is. This paragraph from the survey is telling: "Although educators demonstrate greater knowledge of First Amendment freedoms than the general public, roughly one in five can not recall any of the five freedoms. While three out of four educators recall freedom of speech, fewer than one in four can identify each of the other freedoms." FEWER THAN ONE IN FOUR EDUCATORS SURVEYED COULD IDENTIFY EACH OF THE FUNDAMENTAL FREEDOMS GUARANTEED BY THE FIRST AMENDMENT.
Now, if the teacher is not ignorant of the law then the actions of the teacher can only be described as malicious. There is a clear body of agreed on statements about how to effectuate students' rights in the classroom context. The consensus of those statements is that a student may express religious ideas and opinions in response to school assignments, as part of classroom discussions appropriately.
What does this mean? Well, it means teachers can't downgrade or reject student work because of their inclusion of religious ideas and themes so long as doing so is within an assignment's boundaries. For example, if the teacher assigns all the odd-numbered algebra problems at the end of chapter five, the teacher can downgrade a student who writes, "Buddha, Buddha, Buddha" as the answer to each problem, just as a teacher can downgrade a student that gets the answers wrong but clearly attempted to solve the problem according to the principles set out in the chapter.
On the other hand, if a teacher assigns students to write an essay on the person most influential in the student's life, and provides no other parameter (living person, deceased person, fictional person, factual person, related person, etc.), then the teacher cannot downgrade the student assignment that describes why Mahatma Gandhi or Mohammed or Jesus is the most influential person in that student's life on the claim that the essay's religious content is inappropriate as a violation of the separation of church and state. Doing so reflects a misunderstanding of the law: teachers CAN violate the separation of church and state that the Establishment Clause delineates; students are not government actors and so cannot do so.
