Mark Halperin wants to spend more time writing – “perhaps another book and possibly for a publication.” So he’s stepping down as ABC News political director and becoming “political analyst.”

This will make it possible for us to continue to draw upon Mark’s unparalleled political analysis and knowledge while at the same time giving him some new venues in which to use his talents,” David Westin wrote in a memo to staffers today.

David Chalian is ABC’s new political director. Here’s the full memo…