I have had rival gang members in the same class, and I saw that as an opportunity to impose some sanity — to help those guys see that their enemy might not be whom they thought they were. I have had students who disliked students of other ethnicities, and I appreciated the chance to help them get along. It isn’t easy, but it’s my job. If I had a white student who felt entitled to use the N-word to refer to his African-American peers, I would appreciate that opportunity, too.

Those of us who want our country and our world to be better than it is should know that won’t happen as long as we will only enlighten those whose values we share. No child or young adult ought to be considered beyond hope, at least not by an educator. I haven’t been successful at helping to transform every young person I’ve taught, but I’ve always tried, and I’ve never asked anyone to make a student go away because that student was a problem or because that student had offended me or another student.

In Kashuv, Harvard accepted a student who met its academic criteria but lacked the values it promotes. That was an opportunity — a teachable moment — that Harvard should have embraced.