The President whose cabinet James Mattis served on assumed office on what date?
Cabinet of Donald Trump This article lists the members of President Donald Trump's Cabinet. Trump assumed office on January 20, 2017.
Timeline of the presidency of Barack Obama (2012) The following is a timeline of the Presidency of Barack Obama, from January 1, 2012 to December 31, 2012. For his time as President-elect, see the Presidential transition of Barack Obama; for a detailed account of his first months in office, see First 100 days of Barack Obama's presidency; for a complete itinerary of his travels, see List of presidential trips made by Barack Obama.