The huge bureaucracy of the U.S. government relies on scads of political appointees to implement policies across all the various agencies. When a new administration takes power, the president is responsible for appointing more than 4,000 government officials, and the Constitution requires Senate approval for 1,212 of these positions.
Donald Trump has been slow to nominate and confirm appointees, compared to his predecessors, and he's even vowed that he won't fill all of them (he did promise to "Drain the swamp"). But just because a position is vacant doesn’t mean someone isn’t doing the job; the government continues to function under the stewardship of career civil servants and appointed holdovers from the previous administration.
These acting officials, however, are essentially substitute teachers and lack the political capital to make serious policy changes. And they can only serve in an acting capacity for a limited time — about 10 months — before they must hand off duties to the appointee or another acting official. Any acting official who starts after the first 90 days of a new administration gets a 210-day term before they must give up the reins.
Check out the video below to see how this could affect Trump’s ability to successfully manage the government and follow through on his agenda.