Growing field of GOP candidates in dash to White House

The Republican presidential field is set to expand this week to six candidates. Former Arkansas Gov. Mike Huckabee, former Hewlett-Packard CEO Carly Fiorina and retired pediatric neurosurgeon Dr. Ben Carson are all entering the race. CBS News political director and future "Face the Nation" host John Dickerson joins "CBS This Morning" to discuss the race for 2016 and the impact of new book "Clinton Cash."