trying to bring order to a chaotic administration. the president clearly taking his departure personally. >> boris, thank you so much, really appreciate it. for more on the early departure of the defense secretary, cnn's barbara starr. what do we know about patrick shanahan? >> reporter: he's been fulfilling the traditional role of the number two at the defense department, working on the organization of the pentagon, budget, funding, acquisition, innovation, getting that space command set up that the president wants. these are all the business executive issues very close to the president's heart. shanahan comes from a 30-year career at boeing, so he's very familiar with these kinds of things. it's interesting, kate, he hasn't been in the position of having to say no to the president, and that may be the big difference now, as shanahan steps on the world stage.