I like to assume that educators chose their line of work not because they enjoy wielding arbitrary power over children or because education is an easier major than theoretical physics, but because deep in their hearts they are idealists. And so I wonder how they feel when instead of teaching they find themselves running internment camps for political dissidents.

My daughter Emma, a ninth-grader, was suspended from school this week for joining an anti-war march. On March 20, the day after hostilities in Iraq began, the school’s principal, Joseph Freed, received word (from student informers) that a walk-out was to take place. He announced that anyone who joined was subject to suspension and that the leaders would be recommended for expulsion.

When the group of local university and high school students arrived at the school, he posted teachers at the doors, to block students and to make a list of escapees. Only one student actually got away and joined the march: Emma. She was suspended, along with a student who had left earlier in the day. Another student was sent home, though not officially disciplined, for calling the principal a “fascist.”

Such scenes have been common in America’s schools since preparations for war began. In New Mexico, a teacher was suspended for allowing his students to read anti-war poetry on the school’s closed-circuit television. Students were suspended in Red Hook, NY for participating in a march. Students in Michigan, Chicago, Colorado, and elsewhere have been disciplined for wearing anti-war t-shirts or posting anti-war messages.

The administrators at Emma’s school emphasized that they were required to take the action they did for the safety of the students. And they were reasonably nice about the whole thing: though they pressed Emma to say she was wrong, they did not pound on her to recant, as did the apparently Stalinist administrators of my junior high when I led a walkout during the Vietnam war.

But this just cannot be the way we prepare children to live in a democracy. Whether children have first amendment rights is a vexed legal question, but what is not in question is that they someday will. Constraining them from expressing their views is no preparation for exercising those rights.

The whole thing comes with the traditional blah-blah of American mega-education, about “disruption” and “permanent records”: the empty threats, the ideological mumbo-jumbo, the informers, the files, the claims of bureaucrats that they are just doing their jobs.

An assistant principal pointed out to me that if Emma had just waited a half hour, the school day would have been over and there would have been no problem. But it is important to walk out of school precisely because of the sort of authority that school officials claim over children.

Blocking the doors, making threats over speaker-systems, jotting down names: these are local manifestations of the same sort of authority that is twisting the arms of countries to join our “coalition” and that, ultimately, is lobbing missiles into Baghdad.

That’s why, first of all, schools can’t allow protest. And that’s why defiance is required.

Crispin Sartwell teaches philosophy at the Maryland Institute College of Art.