since general mattis left. there's a lot of, again, long-term planning and extern things that the secretary of defense can do when he or she is confirmed by the senate. a lot better communication with congress, for instance. congress can hold the secretary of defense to what the secretary says in those confirmation hearings and also externally and internationally we have the nato summit this week, a number of ministers of defense will be meeting in brussels. the acting secretary will be there, mark esper with who's expected to be nominated by president trump for the permanent position. but what defense experts tell me it's different. the sense of temporary never really leaves the mind of people dealing with an acting secretary of defense. >> the president's pick right now, at least the acting secretary mark esper, talk about the leadership changes that would have to come if he is d nominated and confirmed by the