Washington Post opinion writer David Ignatius checked the “overstated” uproar over Hillary Clinton's email use as secretary of state, citing national security legal experts who roundly dismiss the idea that any criminal mishandling of classified information occurred.

In an August 28 post describing “The Hillary Clinton e-mail 'scandal' that isn't,” Ignatius cited legal experts and agency officials to explain how Clinton's use of a private server is “not something a prosecutor would take to court” and how transmitting unmarked, then retroactively classified emails does “almost certainly not” constitute a crime:  

Does Hillary Clinton have a serious legal problem because she may have transmitted classified information on her private e-mail server? After talking with a half-dozen knowledgeable lawyers, I think this “scandal” is overstated. Using the server was a self-inflicted wound by Clinton, but it's not something a prosecutor would take to court.

“It's common” that people end up using unclassified systems to transmit classified information, said Jeffrey Smith, a former CIA general counsel who's now a partner at Arnold & Porter, where he often represents defendants suspected of misusing classified information.

[...]

Clinton's use of a private e-mail server while she was secretary of state has been a nagging campaign issue for months. Critics have argued that the most serious problem is possible transmission of classified information through that server. Many of her former top aides have sought legal counsel. But experts in national-security law say there may be less here than it might appear.

First, experts say, there's no legal difference whether Clinton and her aides passed sensitive information using her private server or the official “state.gov” account that many now argue should have been used. Neither system is authorized for transmitting classified information. Second, prosecution of such violations is extremely rare. Lax security procedures are taken seriously, but they're generally seen as administrative matters.

[...]

Informal back channels existed long before e-mail. One former State Department official recalled the days when most embassies overseas had only a few phones authorized for secret communications. Rather than go to the executive office to make such a call, officers would use their regular phones, bypassing any truly sensitive details. “Did we cross red lines? No doubt. Did it put information at risk? Maybe. But, if you weren't in Moscow or Beijing, you didn't worry much,” this former official said.

Back channels are used because the official ones are so encrusted by classification and bureaucracy. State had the “Roger Channel,” named after former official Roger Hilsman, for sending secret messages directly to the secretary. The Joint Chiefs of Staff had a similar private channel. CIA station chiefs could send communications known as “Aardwolves” straight to the director.

Are these channels misused sometimes? Most definitely. Is there a crime here? Almost certainly not.

Ignatius also knocked down conservative media's oft-repeated refrain that Clinton's email use was akin to David Petraeus' crimes, noting how intent to mishandle classified information is central to culpability:

Potential criminal violations arise when officials knowingly disseminate documents marked as classified to unauthorized officials or on unclassified systems, or otherwise misuse classified materials. That happened in two cases involving former CIA directors that are cited as parallels for the Clinton e-mail issue, but are quite different. John Deutch was pardoned in 2001 for using an unsecured CIA computer at his home to improperly access classified material; he reportedly had been prepared to plead guilty to a misdemeanor. David Petraeus pleaded guilty to a misdemeanor in April for “knowingly” removing classified documents from authorized locations and retaining them at “unauthorized locations.” Neither case fits the fact pattern with the Clinton e-mails.