Last month, a New Mexico teacher was Last month, a New Mexico teacher was caught on tape denouncing President Trump in class. “If you have a history teacher teaching you that Trump is good then I feel really scared for you,” the teacher said, in response to a 10th-grader’s question.

The school district’s superintendent said he was “very concerned” about the teacher’s comments, but he had “no problem” with a student recording her.

I’ve got a problem with both. The teacher should be disciplined if she was trying to slant her students against President Trump, which violates her professional duty to educate rather than propagandize. But students should also be prevented from surreptitiously recording in our schools, which deprives teachers of their professional discretion.

It’s a vicious circle. We don’t put enough trust in our teachers, so we empower students to spy on them. And every time a teacher violates her professional trust, the campaign to spy on teachers gets stronger.

In June, a New York high school teacher was reprimanded by the city’s Department of Education for In June, a New York high school teacher was reprimanded by the city’s Department of Education for calling Trump a “rapist” and a “dictator.” The teacher also criticized a student who wore a pro-Trump “Make America Great Again” hat. How do we know? A student recorded him, of course, and sent a tape of his remarks to school investigators.

In North Carolina, meanwhile, a teacher was In North Carolina, meanwhile, a teacher was caught on tape last year telling her class that “the only people who seem to be safe” from Trump are “white Christian males.” The tape caused an uproar when it was posted online, and the teacher resigned.

It’s not just anti-Trump teachers who have been secretly recorded. Last fall, a few days after Trump was elected, a tape surfaced of a Los Angeles substitute teacher gleefully telling students that their parents would be deported.

In all of these cases, school officials noted — correctly, of course — that the teachers’ behavior was inappropriate. But nobody pointed out that it was also inappropriate for students to record them.

If you believe otherwise, consider what happened to California teacher Virginia Franklin in 1963. With the Cold War still blazing, Franklin had come under fire from the American Legion for assigning articles that criticized as well as praised U.S. nuclear policy vis-à-vis the Soviet Union. “She tells the students, ‘Here’s democracy and here’s communism. Choose what is right,’” a local Legion commander complained. “I don’t believe we should do that in this country. There’s too much chance of influencing the wrong way in the classroom.”