Here's why James Comey didn't recommend prosecution for Hillary Clinton

Republicans are puzzled about why it is FBI Director James Comey declined to recommend prosecuting Hillary Clinton, but they'll have a chance to ask him about his reasoning Thursday, when he testifies before Congress.

Count Paul Ryan among the confused. "What I don't really understand is after he lists this laundry list of violations, he comes to that conclusion," said Ryan Wednesday.

But prosecutors have a different view. The standard they use is willfulness. Comey himself said Tuesday that the cases the FBI has historically prosecuted have involved one or a combination of the following:

• "clearly intentional and willful mishandling of classified information;
• or vast quantities of materials exposed in such a way as to support an inference of intentional misconduct;
• or indications of disloyalty to the United States;
• or efforts to obstruct justice."

It's that first standard -- willfulness -- that sets the high bar. "The most difficult element to satisfy is the willfulness requirement," said veteran prosecutor James Melendres, a partner at Snell & Wilmer.

To prove that any crime was committed, he explained to CBS News, you have to show willfulness in the mental state of the defendant. In Clinton's case, that means proving that she "had an evil intent" and that she knew what she was doing was wrong. And based on what Comey said, "the FBI team did not uncover any evidence that would satisfy them that there was proof of willfulness," Melendres surmised.

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In court, before a jury, it's incumbent on the prosecutor "to prove the defendant intentionally and voluntarily committed a crime," former federal prosecutor Jon Lenzner, now the CEO of Investigative Group International, told CBS News.

Comey's conclusion led presumptive GOP nominee Donald Trump to complain that "the system is rigged" in Clinton's favor, and that Gen. David Petraeus (Ret.) "got in trouble for far less."

But the case against Petraeus was, in fact, far more clear. Melendres, who was the lead prosecutor against David Petraeus, compared his case to Clinton's. In Petraeus' case, "the FBI uncovered an audio recording that included a conversation between the former CIA director and his biographer [Paula Broadwell] about the classified information that he ultimately shared with her." In that recording, Broadwell asked Petraeus when he would show her the information, and he explained to her that it was highly classified. And then, he told her he'd share it with her. Petraeus then went on to lie to the FBI when he was asked about it.

In Clinton's case, on the question of whether there was intentional misconduct, indications of disloyalty to the U.S. or obstruct justice, Comey concluded, "We do not see those things here."

There is a lower standard that the FBI director mentioned, however, which is that of gross negligence. "Our investigation looked at whether there is evidence classified information was improperly stored or transmitted on that personal system, in violation of a federal statute making it a felony to mishandle classified information either intentionally or in a grossly negligent way," Comey said Tuesday.

He was referring to part of the Espionage Act, section (f), says Melendres. To meet that standard, according to Lenzner, prosecutors could be looking for instances of large-scale transmission of classified documents, for instance. The classified emails might have been delivered to improper entities like foreign government actors, members of the media, or, say, your biographer, Lenzner said, referring to the Petraeus case. "Just sending between Clinton and her staff might not meet the standard," he added.

Theoretically, a felony prosecution could be based on this, but it's not likely, Melendres said. "It is exceedingly rare for the department or FBI to base a felony prosecution on that lower standard. I have no knowledge of it being used before."

Neither Melendrez nor Lenzner seemed surprised by the brief time that elapsed between Clinton's FBI interview Saturday and Comey's announcement Tuesday. When the interview comes at the end of the investigation, that "formal interview is unlikely to be the thing that the case turns on," said Lenzner. The case, he said, would have been made on objective, independent evidence like the emails. If the FBI has gone through all of that evidence over the past year -- as Comey indicated they had -- "the interview with her is not going to be as crucial." Typically, investigators would be leaning in one direction or the other before that interview began, Lenzner added.

That interview with Clinton, rather, was likely the time to answer questions that had been deferred to her by other people who were interviewed -- to confirm facts and to be comprehensive, suggested Lenzner. If evidence had led them to believe she had committed a crime, Clinton would have been interviewed earlier in the investigation.

On Wednesday afternoon, Attorney General Loretta Lynch received and accepted the FBI's "unanimous recommendation that the thorough, year-long investigation be closed and that no charges be brought against any individuals within the scope of the investigation."

In:
• Federal Bureau of Investigation
• James Comey
• Hillary Clinton