Now that the strike is over and teachers are back in school, it's a good time to visit the story of David Corral, the UNO charter school teacher summarily fired after he notified officials of a "mock rape" in the boys' locker room.

That's UNO, as in one of the state's fastest-growing charter school operations, whose CEO, Juan Rangel, is a close political ally of Mayor Rahm Emanuel's, as he was of former mayor Richard Daley's. Which helps explain its rapid expansion. Corral's story may give you an idea of what our school system might be like if the mayor's anti-union allies succeed in stripping teachers of their rights—that is, a place where administrators have the unlimited ability to fire teachers for any reason they choose.

In the summer of 2008, Corral, after answering a help-wanted ad on Craigslist, signed a one-year, $47,000 contract to teach gym at UNO's Garcia High School in Archer Heights on the southwest side.

Corral, 37, seemed ideal for UNO. Like many of his students, he was born in Mexico and raised on the southwest side, where he still lives. He graduated from Farragut high school, got a degree from UIC, and worked for several years at a Boys & Girls Club in Bridgeport.

His first year at UNO went so well that Rangel signed him to another one-year contract, raising his salary to $52,000.

As he soon discovered, teaching for UNO presented some curious contradictions. On one hand, UNO's students—like teenagers everywhere—could be obnoxious, or worse. In one instance, when Corral was absent, some boys called the substitute teacher the n-word.

On the other hand, Rangel keeps teachers in line with a host of rigid rules and regulations, like mandating that teachers record attendance no more than five minutes after class starts.

To comply, Corral gathered students in the gym for attendance before sending them to change in the locker rooms. While they changed, he filed the attendance into UNO's system using a wireless computer.

But on November 24, 2009, his computer was low on batteries. So he walked into his office—a small room just off of the gym—to plug his computer into the socket and record attendance. At most he was in his office—roughly 40 feet away from the lockers—for about two minutes, he says.

Afterward, he started class. That's when he noticed that one boy—call him Jerry—was missing, though he'd been in the gym for attendance.

Corral went into the locker room and found Jerry standing shirtless—his eyes watery, as though he'd been crying. "I asked him, 'What happened?' He said, 'Nothing,'" says Corral. "But I knew something was up."

As he went back to the gym to begin class, Corral texted a school counselor: "Someone was bullying [Jerry] and he's not talking. He was dragging in the locker room and when I walked in, his back and chest were all red, like he was fighting."

That text set off a chain reaction that eventually led to several students being called to the office. This was taking place on the Tuesday before Thanksgiving. Josephine Gomez, the school's director—the title UNO gives its principals—was out of town. Rangel was on vacation in Cancun, Mexico.

Before the day was out, school officials pieced the story together. One boy—call him Sam—had held Jerry's arms behind his back while another boy—call him Ishmael—had rubbed his genitalia against Jerry's body.

Ishmael was clothed, so it wasn't skin on skin—one student called it a "mock rape." In resisting the attack, Jerry fell on the ground and feigned injury so the boys would stop.

School officials called police and Ishmael and Sam were handcuffed and arrested. But Jerry didn't press charges and the cases were dropped. Both boys were back in school after two-day suspensions.

At first, school officials praised Corral, noting he'd followed the law, immediately reporting a potential incident of sexual abuse. "Thank you for all you are doing to help us understand what occurred in the locker room today," Gomez e-mailed Corral and two other staffers. "I thank you for the dignity that you have in attending to the matter respectfully and privately. I am here for you, whatever you need. Do not hesitate to call. Know that you have my respect."

But within several days, school officials flip-flopped. On December 4 Corral was called to a meeting with Gomez and Sister Barbara McCarry, UNO's director of academics. "Sister Barbara stated that I was being terminated because UNO felt the incident could have been prevented if I would have spent more time supervising the locker rooms," says Corral.

Corral pleaded his case. Yes, he'd stepped into his office. But it had only been for about two minutes. Even if he'd remained in the gym, he wouldn't know what was happening in the locker room because the students weren't screaming. He couldn't "supervise" the boys' locker room without leaving the students who'd already gotten dressed and come back into the gym. And he couldn't supervise the girls' locker room at all.

In short, he was fired for not doing what couldn't be done. "It's physically impossible to be in the boys' locker room, the girls' locker room, and the gym at the same time," he says.

But the decision was final, McCarry told him. Security guards escorted Corral out of the building as students, parents, and other teachers watched.

Within a few months he hired a lawyer, Elaine Siegel, and on June 2, 2010, he filed a suit claiming he'd been fired "for reporting suspected child abuse." He asked for back pay plus damages. The case has been dragging on in federal court ever since.

But some illuminating details have surfaced in discovery. Siegel got a copy of an e-mail in which McCarry said she'd notified Rangel of the locker room incident two days after it happened, when she'd finally tracked him down in Cancun on Thanksgiving. "Juan is ready to fire the gym teacher," McCarry wrote. In other words, Rangel dismissed Corral without hearing his side of the story, then or since.

During a deposition, Siegel asked Rangel why Corral had been terminated for not doing what he couldn't do. "If somebody set up classes so that it was physically impossible for the students to be under direct supervision at all times, is that a violation of UNO policy?"

"Like a teacher going into their office to do attendance?" Rangel responded.

"No, like a teacher not being in two locker rooms at the same time?"

"While they're in their office taking attendance, I think that would be a violation of UNO policy," Rangel said. "They're not supervising the children, they're doing something else."

Corral says Rangel used him as a "scapegoat" to send a message to the staff. "I believe Rangel fired me because the police came to school and took those kids in handcuffs," says Corral. "That was an embarrassment—someone had to pay."

Rangel did not respond to a request for comment.

Had Corral been a unionized teacher in a regular public school, he couldn't have been summarily fired without an official investigation in which he could testify. In fact, one reason the union struck was to protect teachers like Corral, who claim autocratic bosses have unjustly punished them.

But UNO, like most charters in Chicago, is nonunion, though it receives more than $30 million a year in public funds. As such, its teachers are at-will employees, who can be fired "at any time for any legal reason or for no reason, with or without prior notice," as Corral's contract stipulates.

As I said, UNO's one of Mayor Emanuel's favorite charter school networks—they have 13 branches throughout the city, including two that opened this year. Rangel supported Emanuel in the 2011 mayoral election. The mayor appointed Rangel to the Public Building Commission, which doles out the money for publicly funded construction projects, like new schools. As a matter of fact, Mayor Emanuel and Governor Pat Quinn showed up when UNO opened its latest publicly financed school in the northwest side's Galewood neighborhood. Rangel won the zoning approval even in the face of community opposition.

As he hands out more contracts to nonunion charters, Mayor Emanuel also vows to replace "bad" teachers with "good" ones.

Let's hope he knows which one's which.