Tough-as-nails long-time Clinton adviser Williams (above, left) to formally take over.
Williams has played a more active role after Iowa loss.
Outgoing topper Patti Solis Doyle to stay on as senior adviser to the campaign.
Read Solis Doyle's email message to her staff here.
Read Clinton's statement here.
Swampland's Karen Tumulty, The Fix's Chris Cillizza, and The Swamp's Mark Silva are all talking about the move.
