Two days from the inauguration, President-elect Joe Biden and Vice President-elect Kamala Harris are pitching in on Martin Luther King Jr. Day service projects. Their work comes as a militarized and jittery Washington prepares for a swearing-in that will play out under extraordinary security. Biden and his wife, Jill, joined an assembly line in a Philadelphia parking lot, filling food boxes for people in need. Vice President-elect Kamala Harris also took part in a service event in Washington. Some 25,000 National Guard troops were being dispatched across the city to bolster security. Monuments — including the King memorial — are closed to the public until after Wednesday’s inaugural events.