One of President Barack Obama's top lieutenants, 2008 campaign manager David Plouffe officially endorsed Hillary Clinton on Saturday. "Now, to be honest, during the most intense days of the 2008 primary, I would never have imagined writing this piece. And I doubt Team Clinton felt any differently about me," Plouffe wrote in a post on Medium. Other top Obama officials, most notably David Axelrod, have not endorsed. "Americans still need a president who will wake up every day, prepared to overcome any obstacle on their behalf. Hillary Clinton should — and I believe will — be that president," he wrote. Plouffe has reportedly been involved behind the scenes on the Clinton campaign.