Managers & Supervisors promote their own.

Tha Best Man?

I read this from Tom Clancy. "Corrupted men only select other corrupter men to be their peers."
That reminds me of my air force career. Drunks promote drunks, cad players promote card players, and golfers promote golfers. It's the same in every business. I expect it's the same at the White House security. Then there's that Ebola farce in Texas.