And they protect the US Secretary of State, too, but look at how hard Colin Powell made their job:
https://wikileaks.org/clinton-emails/emailid/30324
It's in the PDF attached to that. There's always a weak link somewhere. When you have people like this in power, even the smartest spies can't protect them --
"Now, the real issue had to do with PDAs, as we called them a few years ago before BlackBerry became a noun. And the issue was DS would not allow them into the secure spaces, especially up your way. When I asked why not they gave me all kinds of nonsense about how they gave out signals that could be read by spies, etc. Same reason they tried to keep mobile phones out of the suite. I had numerous meetings with them. We even opened one up for them to try to explain to me why it was more dangerous than say, a remote control for one of the many tvs in the suite. Or something embedded in my shoe heel. They never satisfied me and NSA/CIA wouldn't back off. So, we just went about our business and stopped asking. I had an ancient version of a PDA and used it. In general, the suite was so sealed that it is hard to get signals in or out wirelessly."
Take, for example, the leaked emails. They can be shown to have DKIM signatures which are signed by both Google & Hillary's email servers and these can be validated. Or in the physical world, you can show that people were in the right place in the right time. You can find multiple, named witnesses who have proof of being in the right place at the right time and other corroborating evidence.
Sure, it will be disclaimed as being faked. But then you end up like Donna Brazille:
- First you show her denying this: https://www.youtube.com/watch?v=Izl0e4xvgGA
- Now you show a DKIM validated email: https://wikileaks.org/podesta-emails/emailid/5205
- Now you show how to perform the validation: http://blog.erratasec.com/2016/10/yes-we-can-validate-wikile...
At this point, they can deny however they like. It only makes them look more guilty.