 Our chief White House correspondent, Mary Bruce, who, of course, is at the White House. She has been reporting on this for weeks now. Mary, these are extremely fast moving developments. The president now saying that he's going to step aside. He's officially endorsing Vice President Kamala Harris. We're learning that the DNC expected to hold a call later this afternoon. This has to move extremely quickly. And we're also learning that even some of the president's aides and advisers were caught off guard by this announcement.