DonDiego has discovered an excellent explanation of the proper handling of classified information:
What Everyone with a Top Secret Security Clearance Knows - or Should Know
Some highlights:
__A Clinton spokesperson responded that “Any released emails deemed classified by the administration have been done so after the fact, and not at the time they were transmitted.” Clinton claims unequivocally her email contained no classified information, and that no message carried any security marking, such as Confidential or Top Secret.
The key issue in play with Clinton is that it is a violation of national security to maintain classified information on an unclassified system.
Yet even if retroactive classification was applied only after Clinton hit “send” (and State’s own Inspector General says it wasn’t), she is not off the hook.
What matters in the world of secrets is the information itself, which may or may not be marked “classified.” Employees at the highest levels of access are expected to apply the highest levels of judgment, based on the standards in Executive Order 13526. The government’s basic nondisclosure agreement makes clear the rule is “marked or unmarked classified information.”
__The emphasis throughout the classification system is not on strict legalities and coded markings, but on judgment. In essence, employees are required to know right from wrong. It is a duty, however subjective in appearance, one takes on in return for a security clearance.
“Not knowing” would be an unexpected defense from a person with years of government experience.
__Every email sent within the State Department’s own systems contains a classification; an employee technically cannot hit “send” without one being applied. Just because Clinton chose to use her own hardware does not relieve her or her staff of this requirement.
__Some may say even if Clinton committed security violations, there is no evidence the material got into the wrong hands – no blood, no foul. Legally that is irrelevant. Failing to safeguard information is the issue.