The talking point has gained steam this week after FBI Director James Comey recommended that the Justice Department bring no charges against Clinton, with presumptive Republican presidential nominee Donald Trump even suggesting a nefarious motive behind the decision.
On Thursday, Comey was given an opportunity to rebut some of those charges during a hearing on Capitol Hill before the House Oversight and Government Reform Committee.
"The Petraeus case, to my mind, illustrates perfectly the kind of cases the Department of Justice is willing to prosecute," Comey told the committee.
Petraeus, the four-star general who oversaw military operations in both Afghanistan and Iraq, resigned as CIA director in 2012 after his extramarital affair with his biographer, Paula Broadwell, became public.
The FBI and Justice Department later recommended felony charges against him for sharing classified information with Broadwell. He ultimately avoided jail time after pleading guilty to a misdemeanor last year, resulting in two years probation and a $100,000 fine. At the time, members of Congress from both sides of the aisle rallied to Petraeus' defense and criticized the Justice Department for pursuing the case.
Republicans have argued that Petraeus' malfeasance was petty, especially relative to Clinton's use of a private email servers.
Trump has made that point repeatedly. In April, he predicted that Clinton would not be indicted.
"I know for a fact that what Gen. Petraeus and others have done was much less," Trump said at the time, adding that Democrats were protecting Clinton from legal fallout.
Trump invoked a nearly identical line Tuesday, after Comey announced his recommendation to bring no charges against Clinton.
"The system is rigged," the GOP nominee said on Twitter.
At the hearing on Thursday, Democratic Rep. Elijah Cummings, the committee's ranking member, invited Comey to counter those claims.
Comey pointed out that Petraeus not only shared the classified information, but also hid the documents in his attic and then lied to investigators.
"So you have obstruction of justice, you have intentional misconduct and a vast quantity of information," Comey said. "He admitted he knew that was the wrong thing to do. That is a perfect illustration of the kind of cases that get prosecuted."
He added: "In my mind, it illustrates importantly the distinction to this case."
Comey was called to Capitol Hill
by Republicans who were left frustrated over his decision to recommend no charges against Clinton.
On Tuesday, Comey said Clinton was "extremely careless" in her handling of classified information, but that "no reasonable prosecutor" would bring a case against the presumptive Democratic presidential nominee.
Rep. Jason Chaffetz, the Republican chairman of the House Oversight Committee, said at the hearing on Thursday that he was "mystified and confused" by the conclusions Comey reached.
"It seems to a lot of us that the Average Joe, the average American, that if they had done what you laid out in your statement, that they would be in handcuffs and they might be on their way to jail," Chaffetz told Comey.