"At noon on January the 20th 2017, the President-elect will be sworn in and assume the duties of President of the United States. While the President is feted with an Inaugural Parade and many formal balls, the new Secretary of Defense immediately begins a day filled with briefings, staffing decisions, war-plan reviews, and meetings with the Chair and Vice Chair of the Joint Chiefs of Staff and the combatant commanders. That long day and all those to follow leave little time for the Secretary to set a strategic agenda. If there is to be one, it should be ready before day one. The only time to do that work is between the Secretary Designee's selection and the swearing-in ceremony. The Secretary's first days in office are further complicated by the fact that, in most previous transitions, there were many vacancies among the senior political appointees, leaving insufficient numbers of people in the Pentagon with statutory authority to make decisions and keep the Department operational and running on course. The outgoing Administration's political appointees typically expect to be replaced and have for some time been preparing for life after the Pentagon. Without clear signals of intent from the Transition Team, many of the very best will have found jobs and departed before January 20th, leaving gaps in the Secretary's leadership team. Even as the new team ramps up, many past Secretaries have found themselves initially surrounded by more people with backgrounds focused on developing policy, than with the backgrounds in strong leadership and management; skills that are necessary to manage the Department. This is because the transition is often built from the policy-experienced individuals that support the campaign issue teams. The managerial talent necessary to run the details of an enterprise the scope and scale of the Department are typically only sought later in the campaign or after the election."
Defense Business Board: http://dbb.defense.gov/