I think you mean why has NOT POTUS left the White House. My gut tells me, the threat level has gone up, since December.  First trying to kill him at the Christmas Tree Lighting Ceremony.  Then a marine that went rogue, at Christmas and he to be put down by Secret Service.  And NOW, it appears more threats under way.  Can't wait till these satanic psychopaths get cuffed and hauled off to GIMO!