As Pennsylvania Attorney General Kathleen G. Kane has been speaking out against a sting investigation aimed at corrupt politicians, defense lawyers in other high-profile cases have been listening.

They hope to use her words against her.

In vigorously defending her decision to shut down the sting, Kane has taken aim at everything from the legal theory behind the case to the motives of the prosecutors who ran it.

In the process, the defense lawyers say, she has raised issues they could use to challenge two of the highest-profile cases her office is handling: one alleging corruption at the Pennsylvania Turnpike Commission and another a cover-up of sex abuse at Pennsylvania State University.

Jeffrey M. Lindy, a Philadelphia defense lawyer who does not have a client in either case, said Kane had been making "monumental policy announcements" that have undermined her own side.

"Look, I'm on the defense side," Lindy said. "But the system doesn't work unless both sides are equally armed. Right now, I believe what she's doing is giving a lot of ammunition to the defense."

Since The Inquirer revealed the aborted sting on March 16, Kane has said she had no choice but to end the investigation without bringing criminal charges, even though sources say the operation captured five Philadelphia Democrats pocketing cash or gifts.

Kane said the inquiry never nailed down what she called "the critical criminal element" of a quid pro quo: money "directly in exchange for official action."

Critics of the investigation point out that the sting's undercover operative paid his targets to vote against a bill they already opposed.

In the turnpike case, defense lawyers have seized on the attorney general's statement, even coining a phrase for it: the "Kane doctrine."

If the "Kane doctrine" requires a prosecutor to document a clear quid pro quo in corruption cases, they say, their clients should have all charges dismissed because the state cannot show they steered specific contracts in return for gifts.

Kane says her analysis of the sting case has no bearing on the turnpike prosecution. In the turnpike case, prosecutors allege seven defendants - politicians, turnpike administrators, and businessmen - traded campaign contributions and gifts for contracts.

"This is apples and oranges," her spokesman, J.J. Abbott, said last week.

"An 85-page grand jury presentment detailed an elaborate scheme by the defendants to enrich themselves in exchange for turnpike business. These arguments by the defense are a desperate attempt to distract from the alleged crimes of their clients."

The stakes are high in the turnpike case and the pending trial in which Penn State's former president and two former administrators are charging with trying to cover up former coach Jerry Sandusky's wrongdoing. The cases involve prominent defendants, powerful institutions, and an attorney general whose record will be shaped by their outcomes.

David Shapiro, who represents former Turnpike Commission Chairman Mitchell Rubin, said Kane was right to call for an explicit quid pro quo in corruption cases. He said that was precisely what was lacking in the turnpike case.

"The issue is the quid pro quo evidence. We have no idea what it is," Shapiro said at a hearing last month crowded with defense lawyers. "Not anybody on this side of the room has any clue as to what the link is between the contributions and the contracts."

William Fetterhoff, another defense lawyer in the case, said last week the Kane doctrine might influence how the judge instructs the jury.

"It's a question of the jury being made aware of the fact that these two isolated acts - campaign contributions on the one hand and contracts on the other - don't establish bribery," Fetterhoff said.

The prosecutor in the turnpike case, Senior Deputy Attorney General Laurel Brandstetter, has argued that the Attorney General's Office need not draw such a tight connection.

The defense's "emphasis on quid pro quo and bribery is a very narrow view," Brandstetter said at one hearing last year well before the sting case ignited a public debate.

Michael J. Engle, lawyer for a contractor charged in the turnpike case, said the defense would highlight Kane's remarks in legal filings next month seeking to have the case dismissed ahead of trial.

Although the judge in the case has so far not endorsed their analysis, Engle said, "it's completely relevant and will be raised again. We're not done with it."

Engle said Kane had undercut Brandstetter, the prosecutor in the case.

"It would seem to be a more difficult argument now that the chief law enforcement officer of the commonwealth is saying something directly opposite," Engle said.

But Daniel Richman, a former federal prosecutor who is a law professor at Columbia University, said the contradiction might be more apparent than real.

He said corruption cases invariably turn on the nitty-gritty interactions between politicians and their benefactors. He said Kane could have plenty of reason to find a quid pro quo in one context and not another - in one criminal investigation, but not another.

Bruce Ledewitz, a law professor at Duquesne University, also criticized the defense arguments. He said defense lawyers would likely fail if they sought to use Kane's public remarks in a courthouse.

He predicted prosecutors could brush the challenges aside as irrelevant, saying, "Your honor, that may play well in the court of public opinion, but this is a court of law."

In the case against three Penn State administrators - former university president Graham B. Spanier, former athletic director Tim Curley, and finance aide Gary Schultz - Kane finds herself in an awkward position.

In her successful 2012 election campaign, Kane, a Democrat, won votes by raising questions about the investigation into Sandusky and Penn State. She suggested that as attorney general, Republican Tom Corbett had put the brakes on the inquiry for political reasons.

After taking office in January 2013, Kane hired former federal prosecutor Geoffrey Moulton to, in effect, investigate the investigation - led by Frank G. Fina, the former chief deputy attorney who also handled the sting case.

Fina is now an assistant district attorney in Philadelphia. Before he left his state position, he oversaw corruption investigations, including the turnpike case.

If Moulton produces a report that suggests politics tainted the probe, it could cast a shadow over the prosecutions of Spanier and his two ex-colleagues.

Moulton's work has already complicated the prosecution of Spanier, Curley, and Schultz.

In February, Kane announced the Moulton report had been delayed, in part by an effort to obtain e-mail sent by Fina and others during the original Sandusky probe.

Now, defense lawyers in the pending Penn State cases want that e-mail, too.

And they have listened intently as Kane has lambasted Fina's work on the sting to see if they can use her assessment to derail the prosecution's case. Kane has suggested Fina so badly bungled the undercover sting he rendered it "not prosecutable."

Shortly after The Inquirer revealed the aborted sting, Spanier filed a lawsuit in federal court. His allegation: that Fina engaged in prosecutorial misconduct in the Penn State case.

In that case, Kane's office has fought against the challenge to Fina's work and asked a judge to dismiss the suit.