You are a bad person if you send your children to private school. Not bad like murderer bad—but bad like ruining-one-of-our-nation’s-most-essential-institutions-in-order-to-get-what’s-best-for-your-kid bad. So, pretty bad.

I am not an education policy wonk: I’m just judgmental. But it seems to me that if every single parent sent every single child to public school, public schools would improve. This would not happen immediately. It could take generations. Your children and grandchildren might get mediocre educations in the meantime, but it will be worth it, for the eventual common good. (Yes, rich people might cluster. But rich people will always find a way to game the system: That shouldn’t be an argument against an all-in approach to public education any more than it is a case against single-payer health care.)

So, how would this work exactly? It’s simple! Everyone needs to be invested in our public schools in order for them to get better. Not just lip-service investment, or property tax investment, but real flesh-and-blood-offspring investment. Your local school stinks but you don’t send your child there? Then its badness is just something you deplore in the abstract. Your local school stinks and you do send your child there? I bet you are going to do everything within your power to make it better.

And parents have a lot of power. In many underresourced schools, it’s the aggressive PTAs that raise the money for enrichment programs and willful parents who get in the administration’s face when a teacher is falling down on the job. Everyone, all in. (By the way: Banning private schools isn’t the answer. We need a moral adjustment, not a legislative one.)

There are a lot of reasons why bad people send their kids to private school. Yes, some do it for prestige or out of loyalty to a long-standing family tradition or because they want their children to eventually work at Slate. But many others go private for religious reasons, or because their kids have behavioral or learning issues, or simply because the public school in their district is not so hot. None of these are compelling reasons. Or, rather, the compelling ones (behavioral or learning issues, wanting a not-subpar school for your child) are exactly why we should all opt in, not out.

I believe in public education, but my district school really isn’t good! you might say. I understand. You want the best for your child, but your child doesn’t need it. If you can afford private school (even if affording means scrimping and saving, or taking out loans), chances are that your spawn will be perfectly fine at a crappy public school. She will have support at home (that’s you!) and all the advantages that go along with being a person whose family can pay for and cares about superior education—the exact kind of family that can help your crappy public school become less crappy. She may not learn as much or be as challenged, but take a deep breath and live with that. Oh, but she’s gifted? Well, then, she’ll really be fine.

I went K–12 to a terrible public school. My high school didn’t offer AP classes, and in four years, I only had to read one book. There wasn’t even soccer. This is not a humblebrag! I left home woefully unprepared for college, and without that preparation, I left college without having learned much there either. You know all those important novels that everyone’s read? I haven’t. I know nothing about poetry, very little about art, and please don’t quiz me on the dates of the Civil War. I’m not proud of my ignorance. But guess what the horrible result is? I’m doing fine. I’m not saying it’s a good thing that I got a lame education. I’m saying that I survived it, and so will your child, who must endure having no AP calculus so that in 25 years there will be AP calculus for all.

By the way: My parents didn’t send me to this shoddy school because they believed in public ed. They sent me there because that’s where we lived, and they weren’t too worried about it. (Can you imagine?) Take two things from this on your quest to become a better person: 1) Your child will probably do just fine without “the best,” so don’t freak out too much, but 2) do freak out a little more than my parents did—enough to get involved.

Also remember that there’s more to education than what’s taught. As rotten as my school’s English, history, science, social studies, math, art, music, and language programs were, going to school with poor kids and rich kids, black kids and brown kids, smart kids and not-so-smart ones, kids with superconservative Christian parents and other upper-middle-class Jews like me was its own education and life preparation. Reading Walt Whitman in ninth grade changed the way you see the world? Well, getting drunk before basketball games with kids who lived at the trailer park near my house did the same for me. In fact it’s part of the reason I feel so strongly about public schools.

Many of my (morally bankrupt) colleagues send their children to private schools. I asked them to tell me why. Here is the response that most stuck with me: “In our upper-middle-class world, it is hard not to pay for something if you can and you think it will be good for your kid.” I get it: You want an exceptional arts program and computer animation and maybe even Mandarin. You want a cohesive educational philosophy. You want creativity, not teaching to the test. You want great outdoor space and small classrooms and personal attention. You know who else wants those things? Everyone.

Whatever you think your children need—deserve—from their school experience, assume that the parents at the nearby public housing complex want the same. No, don’t just assume it. Do something about it. Send your kids to school with their kids. Use the energy you have otherwise directed at fighting to get your daughter a slot at the competitive private school to fight for more computers at the public school. Use your connections to power and money and innovation to make your local school—the one you are now sending your child to—better. Don’t just acknowledge your liberal guilt—listen to it.