Obama is expected to nominate Ashton Carter as defense secretary . The top names on the White House `` shortlist '' -- which included former high-ranking Pentagon official Michele Flournoy , Homeland Security Secretary Jeh Johnson and Rhode Island Democratic Sen. Jack Reed -- all withdrew themselves from consideration . Carter emerged as the frontrunner after other candidates withdrew . Obama has continued to make second choices for several Cabinet positions .
Obama is expected to nominate Ashton Carter as defense secretary . Carter emerged as the frontrunner after other candidates withdrew . Obama has continued to make second choices for several Cabinet positions .