Concerns the investigation of Christie 's travel expenditures while U.S. attorney . Was included in new book by Christie on presidential campaign , ` ` Double Down '' Christie faces New Jersey voters next week in gubernatorial primary bid . Wolf Blitzer wrote on CNN.com in October 2011 that White House sources told him that the President was `` very high '' on Biden and `` deeply appreciates his advice . '' Book also says Obama has conducted focus groups , talking about replacing Biden with Clinton .
Concerns the investigation of Christie 's travel expenditures while U.S. attorney . Was included in new book by Christie on presidential campaign , ` ` Double Down '' Christie faces New Jersey voters next week in gubernatorial primary bid . Book also says Obama has conducted focus groups , talking about replacing Biden with Clinton .