Just to give the non-educated a slight understanding of security procedures, You can read this article by Kurt Schliechter (who knows of which he speaks), but before you start thinking that Hillary's email troubles are a mistake, an accident, or a lapse in judgement, know that you're wrong. It's simply impossible for any of this to be a mistake or an oversight. Impossible.
After you read Col Schiechter's article, let me tell you a story about a low-ranking officer, myself. Known as Major D by my subordinates, one of my myriad duties during Desert Storm was to provide an MP presence at the post classified document facility. No one got in there without a clearance, and no one brought in or left with papers, notes, briefing books, anything. Occasionally we'd hold briefings there and all the slides were produced on-site. (Old warriors will remember slides and a program called Harvard Graphics, which preceeded PowerPoint, but I digress.)
IDs were checked, coming and going, and my MPs kept the book that logged personnel in and out. Once a week or so, I'd have business there, and I'd park my vehicle in the lot, then walk over to a chain link/barbed wire gate with a TV camera on it, and push the button. The MP at the desk would buzz me through, then I'd get to a steel door, where I'd push another button, and the MP would again buzz me though. Entering that door, I was faced with my MP. I knew these guys by name, and by face, and the conversation went something like this:
MP: "Good afternoon, Major D!:
Me: "How are you, young warrior? Are they treating you okay?"
MP: "Yes, sir. How can we help you today?"
Me: "I need to see Captain McClung. Is he in?"
MP: "Yes, sir, he's in the back. If I could just see your ID."
Those guys worked for me, and knew me by name and face and asked to see my ID before I could proceed into the facility. No papers, no notebook, and yes, by God, I would produce an ID. And this was at a piddling little Army post. The only secrets we kept were large troop movements.
Secrets at the level that the Secretary of State keep are levels of magnitude above the ones I was trusted with. The very idea that classified material was mistakenly sent to her server is an impossibility. That doesn't happen unless some is ready to go to jail.