When it comes to security items that's a entirely different thing than typical criminal cases. To prosecute her it's not just intent but the type of items and if it affected national security and to what degree. Having worked in Govt and having had a security clearance I can tell you that violations occur all the time and for typical cases it's handled administratively meaning the person's security clearance is revoked which means termination if it's permanent. Unfortunately in this case politics is getting in the way.

A case like Petraeus is different because he knowingly gave away security items and that's serious stuff.