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 .
Concerns included investigation of Christie 's travel expenditures while U.S. attorney . Revelation included in new book by reporters on presidential campaign , `` Double Down '' Christie faces New Jersey voters next week in gubernatorial reelection bid . Book also says Obama campaign conducted focus groups , polling about replacing Biden with Clinton .