Thomas Quinn won accolades for his successful campaign to register Philadelphia 18-year-olds to vote, a volunteer effort he launched in addition to a busy schedule teaching social studies at Central High School.

But with a month to go before last fall’s election, Quinn was jolted — and briefly stopped in his tracks — by an accusation from an unlikely person. Then-Pennsylvania Republican Party Chairman Val DiGiorgio said Quinn was engaging in “liberal indoctrination."

Quinn had never met DiGiorgio, but the 1985 Central graduate said he had evidence of Quinn’s engaging in partisan political activity in violation of Philadelphia School District policy. DiGiorgio wrote to Superintendent William R. Hite Jr., calling Quinn’s conduct “a very serious matter” and took his story to the media, showing a photo of what the GOP chair said was an anti-Republican flier Quinn handed out to students.

But the photo DiGiorgio circulated, Quinn said, was a cropped shot of several political posters hanging in a Central staff room. The poster admittedly had a liberal bent, Quinn said, but it hung in a space that has featured others praising President Ronald Reagan and President Donald Trump, and it was never circulated to students.

Quinn was cleared by the district of any charges of political indoctrination, but did receive a disciplinary memo for hanging a partisan poster in a school space.

These days, DiGiorgio has lost his political position after The Inquirer reported that he traded sexually explicit messages with a Republican candidate for Philadelphia City Council. And Quinn is decrying DiGiorgio’s “smear campaign," which he said was “destructive” and “an abuse of his considerable power.”

“The lesson for me is that teachers can’t become political targets for doing their jobs,” Quinn said. “All teachers should encourage their students to vote, regardless of if they live in the city or country, or their political beliefs.”

DiGiorgio did not respond to requests for comment.

Quinn said the former GOP chairman’s actions were an attack on all Philadelphia teachers, timed to coincide with the height of Quinn’s Philly Youth Vote campaign, which organized teachers in every city high school to register eligible seniors to vote and encourage political engagement.

DiGiorgio’s actions attracted national media attention, created enormous personal and professional stress for Quinn, and caused, at least for a time, a chilling effect on the voter registration push.

Still, hundreds rallied to support Quinn in public and in private, and ultimately, his campaign was successful.

The number of Philadelphia 18-year-olds who voted in the November midterm elections jumped by 157 percent, the largest increase of any age group, city officials said. And four Philadelphia schools — Masterman, Central, Dobbins, and Bodine — won Pennsylvania governor’s civic engagement awards for registering high percentages of 18-year-olds.

“We have the power to dramatically and permanently increase teenager voter turnout, so this has undoubtedly gotten the attention of political operatives; however, our campaign was and remains nonpartisan," Quinn said.

Asked to comment on DiGiorgio’s abrupt resignation and the circumstances surrounding it, Quinn declined.

He did, however, say the district ought to “back us up by promoting voter registration in all high schools,” calling for a formal policy encouraging voter registration.

Lee Whack, district spokesperson, noted the school system’s involvement with voter registration efforts, but stopped short of espousing a formal policy on the issue.

“In our school communities, it is important that we strike a balance,” Whack said, “encouraging young people to become engaged citizens while not elevating specific political views.”