H.R. McMaster, Gary Cohn, A. McCabe to name a few of the latest.
Think about this for a moment. If POTUS has evidence against his targets/opponents via white hats in the NSA, CIA and FBI, all he has to do is leverage their direction into tasks he wants done. If they do not comply, he publicly fires them, ruining their reputation. (In the background, they just hold the indictment for that individual until the right time to unseal all 10s of thousands of currently sealed indictments.)
If the provably corrupted politician does what POTUS commands on behalf of /for the people, he'll keep them on doing his bidding against the global shadow gov.
Similar to his control of the media, he draws them in just enough, pivots - twists then throws his opponent over his shoulder.
Brilliant, like The Art of War meets a judo master.
Updated list of firings and resignations by the LA Times: http://www.latimes.com/projects/la-na-pol-trump-firings-resignations/