What finally forced Joe Biden out?

He’d lost the confidence of his party and many Americans and faced with the growing prospect of Donald Trump returning to the White House, the US President acted.  Joe Biden announced he would not be contesting a second term, endorsing his Vice-President Kamala Harris to take the reins.  Today, Washington Post reporter Mariana Alfaro unpacks another historic day in US politics.  Featured:  Mariana Alfaro, Washington Post political reporter