How did Joe Clark become a hero, praised by President Reagan, lauded by students and parents, and held up as an example by Education Secretary William Bennett?

He did it by ousting a few hundred nonperforming, disruptive students from the "blackboard jungle" that was Eastside High School when he took over as principal some six years ago, and by improving the discipline, the academic performance and the physical safety of that Paterson, N.J., institution.

How did Joe Clark become a target of the school board that recently voted to begin drawing up charges of insubordination and unbecoming conduct against him, charges that could lead to his ouster as principal?

He did it by "expurgating" (his word) another 60 students last month.

Clark, interviewed by Ted Koppel on a recent "Nightline" telecast, comes across as almost a caricature of a tough-guy principal. He has the manner of a Hollywood Marine drill sergeant, the diction of a Howard Cosell impersonator and the uncompromising self-righteousness of a Mitch Snyder: not an endearing combination of traits.

But as the hundreds of parents, students and faculty insist, his bitter medicine was what Eastside needed, and continues to need.

Is it?

The newly elected school board clearly doesn't think so. More interestingly, neither does another principal credited with the turnaround of a violence-ridden inner-city high school. Koppel, who presided over the perfectly cast confrontation between Clark and George McKenna, principal of George Washington Prep in Los Angeles, didn't resolve the question. But he got the issue squarely on the table.

McKenna, who also has been cited by the president and the secretary of education, came to George Washington when it was rated as perhaps the worst high school in Los Angeles. "The ambulance services used to park outside the school, because they got $200 every time they took somebody to the hospital," one man familiar with the school told me.

But McKenna eschewed the tough-guy approach, choosing instead to persuade his students that he was on their side against "the system" -- that he understood their frustrations, respected their humanity and, yes, even loved them. It worked.

Clark's idea of kicking out nonperforming students, "miscreants, malcontents and blood-sucking leeches . . . who are just eroding the basic fabric of this nation" appalls McKenna.

"A student should exit because they have become a detriment to the safety and welfare of other students," McKenna said, "not simply because they are reluctant learners or, in fact, victims of the system. . . . If students are deficient, it is because they need more help, and it is up to us to give them more help."

I confess a certain sympathy with both points of view. Like Clark, I worry about a philosophy that says to minority youngsters that nothing is their fault, that "the system" is to blame for all their shortcomings. It is too easy to plant in their minds the devastating notion that their fate is in the hands of those they perceive as the enemy.

But like McKenna, I believe that it isn't enough simply to get rid of nonperformers. Instilling discipline and kicking out the undisciplined are two different things, even though Clark insists that he is simply referring his ousted students to other educational alternatives.

The trouble with the "Nightline" confrontation is that it will lead too many of us to choose between McKenna's liberalism and Clark's no-nonsense conservatism. It is a false choice. Some coaches manage to produce winning teams by intimidating their players; others who achieve success do so by appealing to pride and instilling self-discipline. It's the same with principals. Some succeed with the tough-guy approach, others with respect and persuasion. It's largely a matter of personality. I doubt that Clark could succeed with the McKenna approach, or McKenna with Clark's. (I also doubt that the one is as understanding or the other as uncompromising as their reputations would have it.)

But despite the fact that I'd prefer a McKenna to teach my own children, I can't condemn Joe Clark, who, like his California opposite, has managed to transform a disaster into a successful school.

Whether Clark has violated the rules is for the school board to determine. But his success at Eastside has convinced me of one thing: tough love works too.