[Former Secretary of Defense James Mattis] sought to focus on the merits and substance of issues the way a wonk or military officer would. Often, that meant ignoring the wishes of the president or the political feasibility of his proposals.
[Defense Secretary Mark Esper's] job is a lot tougher than Mattis’s was in the first two years. He’s gotten a generous budget from the Congress and . . . now has to turn this vision on paper into reality.