He’ll duck behind the “intent” part of the statute which most prosecutors do when the decision is “iffy.” The “intent” part of the statute is pure FOG, no measurement system for it at all. (If you want to hide ...)
Emails: Key security features disabled on Clinton's serverNo intent there!
Clinton's State Dept. calendar missing scores of entries
No intent there!
EXCLUSIVE: Hillary Clinton Posted Names of Hidden Intelligence Officials On Her Email
No intent there!
Hillary Clinton Demanded NSA Change Secure Device Rules to Accommodate Her Secret Server
No intent there!
Hillary Caught Illegally Declassifying Documents. It’s a Felony!
No intent there!
The "willful" and "intentional" standards for the other parts of 793 are reasonably well known, but Comey is playing fast and loose by saying that the only reason a prosecution is unreasonable, is due to absence of intent.
Then there is the misdemeanor offense, which has a "knowing" standard. 18 USC 1924 - that one is also "lost in the FOG."