An issue that rarely—if ever—gets play during presidential elections might give Hillary Clinton a surprising leg-up in Pennsylvania.

That’s what was indicated by feedback from a swing-voter focus group that Frank Luntz conducted during the debate. Attendees gave Clinton sky-high feedback during the debate when she criticized private prisons, and said afterward that it’s an important issue in their state. And, of course, that means the issue could help Clinton excite her supporters there and pick up some votes.

Twenty-seven people participated in the focus group (it would have been 28, but Luntz kicked one guy out when he said he planned to vote Trump), and Luntz’s team tracked their responses to the debate as it progressed. A screen visible to the handful of reporters observing the focus group showed when participants felt positively or negatively about what the candidates said.

The lines tracked particularly high for Trump when he bashed the NAFTA trade deal and promised to renegotiate trade agreements. His numbers dropped, and dramatically, when he tried to explain his refusal to release his taxes and his rationale for demanding to see President Obama’s birth certificate.

Clinton had her fair share of ups and downs as well; the Democratic nominee’s favorability among the completely undecided participants fell when she went on a lengthy riff about Trump’s birtherism, and nosed up when she talked about her dad’s small business.

But her numbers among completely undecided voters went high and higher during her discussion of overhauling the criminal-justice system. When she pointed out that crime isn’t nearly as high as Trump suggests and that the system punishes black and Hispanic men more harshly than white men, the favorability number kept going up. And it went even higher when she praised the Department of Justice’s announcement that it would phase out Bureau of Prisons contracts to stop doing deals with private prison companies. And the number went up even more when Clinton reiterated her position to end all federal contracts with the for-profit corporations.

After the debate wrapped up, focus-group participants explained why they liked Clinton’s answer on private prisons so much: Over the last few years, a “Kids for Cash” scandal has rocked Pennsylvania. In 2011, a Pennsylvania judge got a 28-year sentence for accepting bribes from a private prison company owner. The owner paid him to send children to his prison, often violating their rights to have an attorney. Because of the scandal, the AP reported, Pennsylvania’s state supreme court tossed about 4,000 juvenile sentences.

The scandal affected a massive number of people; not just children wrongfully sentenced in violation of their constitutional rights, but also their families, friends, and, well, anyone who reads the news in Pennsylvania. And even though the judge’s sentencing was several years ago, the Kids-for-Cash scandal is still fresh in the minds of swing voters.

A number of Luntz’s focus-group attendees said Clinton’s opposition to private prisons made them think more highly of her. And none saw it as a negative.

Clinton didn’t focus heavily on private prisons during the debate. But it might help her. Though she has led Trump in every public poll of Pennsylvania voters since July, her lead has slimmed. The RealClearPolitics average gave her a 6.6 percentage-point lead as recently as Sept. 22, but now shows her leading Trump by just 2.4 points.

And Trump’s backers hope that lead will vaporize over the next few weeks. If he picks up the Keystone State’s 20 electoral votes, it will be tough for Clinton to forge a path to the White House.

But if Clinton keeps bashing the companies that profit from mass incarceration, it may be a little tougher for him to do that.