A 13-year-old girl was jumped in Cleveland last month. This week, charges were filed against her alleged assailants — all 18 of them.

According to authorities quoted in the Cleveland Plain-Dealer, the girl’s heritage was the catalyst for the beating. She’s white and, apparently, some kids in Cleveland have a bizarre tradition that May 1 is Beat Up A White Kid day.

I’m not making this up. The unnamed girl is recuperating and her accused attackers — 12 girls, six boys, all black or Hispanic between the ages of 9 and 15 — are facing charges of felonious assault, aggravated riot and ethnic intimidation.

I hope no one uses racial oppression to defend the 13-year-old’s alleged attackers. It would be an affront to decency, logic, and, not coincidentally, black and Hispanic people, if anyone sought to justify this event on the basis of some past racial transgression, real or imagined.

What happened in Cleveland was an act of hatred. It offers visceral proof, should any be required, that this contagion is not limited to white folks.

My purpose in bringing it up, though, is not to belabor that obvious point. Rather, it’s to make another point. But first we must turn to the Texas town of Tulia. There, to great media attention, 12 convicted drug dealers were released this week after grave questions were raised about the investigation that landed them in prison.

In 1999, 46 people — published reports say 39 of them are black, seven white but with ties to the black community — were arrested after a one-man sting operation conducted by an itinerant lawman named Thomas Coleman. For his work, he was named Texas’ narcotics officer of the year.

But Coleman was more Barney Fife than Joe Friday.

He kept no notes of his alleged drug buys, unless you count those he claims to have scribbled on his legs. He had no videotape, no fingerprint evidence, no witnesses, no corroboration of any kind other than his sworn word, to indicate that he bought cocaine from whom he said he did. And no drugs were ever found.

Yet the jurors, almost all of them white, sent 38 people — 36 of them black — to prison for terms ranging up to 90 years.

It turns out, though, that Coleman had a shady past. Arrested in 1998 on charges of theft. Reportedly stole more than 100 gallons of gas from county pumps and once skipped town on $7,000 worth of credit debt, for which he later made restitution. Perhaps most telling, he was given to referring to black people by noxious epithets.

Called before an appeals court in March to defend his “investigation,” Coleman was reportedly vague and evasive, leading a judge to name him “the most devious, non-responsive witness this court has witnessed in 25 years.” He was indicted on a charge of perjury.

Yet it was on his word that a diabetic hog farmer who lived in a shack with a dirt yard was imprisoned as a drug kingpin.

I’m often challenged by white readers to explain what I mean when I use the term “systemic racism.” For the record, I mean the difference between a group of idiot kids who allegedly beat up some poor white girl and a system that throws away black life like tissue paper. I mean the difference between converting prejudice into policy and converting it into petty violence. I mean this, right here.

No, we cannot condone what happened in Tulia or Cleveland. But neither can we pretend the effects are the same.

And if my fear for Cleveland is that race will be used to mitigate accountability, my fear for Tulia is that its lesson will go right over our collective head.

Consider: Multiple studies prove to anyone who cares to look that every major system in this country — judicial, educational, medical, financial — is weighted against black people. Yet people are debating whether this debacle means Coleman was racist, or Tulia was or Texas was.

Somehow, they never considered the likelihood that seems most obvious. Maybe it happened because America was.