Ashton Carter was confirmed as US secretary of defense Thursday, taking on the job of supervising the war against Islamic State jihadists in the final two years of Barack Obama's presidency. The Senate - by a vote of 93 to five - easily confirmed Carter, an accomplished defence technocrat, to replace Chuck Hagel as head of the Pentagon. Despite deep divisions between the White House and many Republicans over foreign and US military policy, Carter's nomination encountered negligible resistance and he sailed through the confirmation process with bipartisan support.