To those battling over critical race theory, here is my plea: Don’t stop teachers from seeking the hidden potential of impoverished and minority children, the most important educational movement of the past 40 years.

I have gotten emotional over this because of a just-released University of Virginia doctoral dissertation by Beverly A. Knupp Rudolph: “The Relationship of School Leader Values and Practices to Participation of Black and Latinx Students in Advanced Placement Courses.”

There is some complicated academic verbiage in its 298 pages. But it provides a deep and moving description of how an average suburban high school conquered American education’s widespread bias against students whose families don’t have much money or education.

I have been writing about that problem since 1982. Some would call the issue racism, but it also applies to the inadequate teaching of poor White kids in rural America. A better term might be “classism,” a word I don’t hear or read often.

Rudolph is a North Carolina public high school principal who investigated the transformation of what she describes as “one racially diverse Mid-Atlantic high school.” Following the standard academic approach to sourcing, she gives the school a pseudonym, Trailwood High. She uses made-up names for the educators who over 24 years significantly increased the enrollment in college-level Advanced Placement classes of what she calls “traditionally marginalized populations, including Black and Latinx students.”

According to my data, by 2018 Trailwood had risen to the top 2 percent of U.S. schools in AP and International Baccalaureate test participation despite half of its students being from low-income families. Its enrollment of more than 2,300 is about 44 percent Hispanic, 24 percent White, 19 percent Black and 8 percent Asian.

I stumbled across that school in 1997. I wrote about it often. I thought I had a good idea of what those educators were up to. Rudolph has gone deeper. She describes deft, sometimes ruthless, moves by three successive principals to nudge classists, if I may use that word, out of the way of student progress.

Trailwood students up to then had to pass a test or an interview and get a teacher recommendation to get into AP. Those are among many common barriers to AP participation that signal an emphasis on sorting, not teaching. Some teachers at the school would tell some students to their faces that they were incapable of learning enough to succeed in the class.

In 1987, a new principal arrived who was determined to change that. She was a fearless, shrewd former nun. Her first move was to make the campus disciplined and safe, and collect data on potentially capable students who weren’t being put in courses that led to AP. “When I first got there, I inherited all the assistant principals,” many of whom resisted her ideas, she told Rudolph. So she recruited teachers to help.

They found kids like Katrina Harpe, the real name of a student I knew then. Her parents hadn’t gone to college and did not press that option on their daughter. Her African American father was a computer technician. Her Korean American mother was a retail clerk. Harpe got okay grades in elementary and middle school but was not challenged until the Trailwood High people got hold of her. She took AP and went to Yale. If you are looking for a family physician in Fredericksburg, Va., you will find Dr. Harpe’s website on Google.

At the beginning of the school’s transformation, parents of children long designated gifted expressed fears that the less-advantaged kids coming into AP would lower standards. One staffer told Rudolph that “the superintendent’s office called me and said, “We just want you to know that some people — parents — are saying this isn’t fair to other kids and therefore, they are seeking an attorney.”

There was pressure for teachers to spend more time with students who were already designated gifted than with children who had mere potential. Some parents feared the changes “would subsequently diminish Trailwood’s reputation as a good school,” Rudolph said in her paper.

Her dissertation emphasizes the risks in trying to change that attitude. A staffer told of skepticism “that these kids aren’t able to do the work, that this is all a numbers game, or that all you’re doing is putting kids [in AP classes] just to get higher enrollment — so you look better.”

The principal said at the beginning she didn’t care how the new students scored on the AP exams. “What we cared about is they would take a step into challenging coursework,” she told Rudolph. The difficult lessons produced results. By 2018, Trailwood’s percentage of graduating seniors passing AP tests was nearly three times the national average.

Low-income minority boys triggered even more skepticism than girls like Harpe. “The teacher would say, ‘Uh, I’m sorry, who are you? Why again are you in this class?’ ” a staffer said. A Black counselor organized a weekly lunch, with pizza, for underestimated boys seeking advice and encouragement from peers. A weekly lunch for girls was also organized.

One staffer told Rudolph, “I had to spend a lot of time, not just with the students, but with the teachers, with the counselors, figuring out who my allies were.”

The principal gave the job of guidance head to a counselor from D.C. committed to the plan. That was a way to neutralize Trailwood counselors who were trying to keep students out of AP. Better counselors were recruited. The principal made the head counselor an assistant principal, and made sure that person replaced her as principal when she retired.

The staffers trying to help students into AP found many were reluctant. There were few people with their backgrounds in those classes. They were getting good grades in regular courses, so why make trouble?

The counselor would say, “Hey, the teacher has said you should be in AP English,” and then not take no for an answer. “Here’s the deal,” a counselor said. “We’re going to register you in AP English. And if you have a problem, I’m going to be checking up on you.” The new team provided tutoring and summer classes and persuaded recalcitrant teachers to change their minds or transfer to another school.

This is the heart of what our best schools are doing: showing students how to learn more than we have asked them to learn before.

The resistance to such change may deserve harsh labels such as racism. But in some cases it could be an excessive desire to be kind. Some teachers struggle with a fear that hard lessons hurt kids of all backgrounds.

However we define racism, we should recognize that children of every ethnicity have hidden potential that deserves encouragement. The story of Trailwood shows how difficult, but potentially liberating, that effort can be.