He can fire most of them at will. Except that he's dependent on them to protect his very hide. Or in the case of the heads of military and intelligence agenci

He can fire most of them at will. Except that he's dependent on them to protect his very hide. Or in the case of the heads of military and intelligence agencies, he's desperate just to have someone he can talk to. That's why he keeps hanging on to Brennan, for example.