USA Today reports the Senate Thursday is expected to approve the nomination of Ashton Carter as Defense secretary, installing a long-time Pentagon insider at the top of the nation's war effort. Carter, 60, succeeds Chuck Hagel who never really recovered from a bruising confirmation fight in 2013. Carter, by contrast, easily navigated his confirmation hearing and won unanimous support from the Armed Services Committee. A physicist by training, Carter has served under 11 Defense secretaries and most recently was the No. 2 official there. President Obama passed him over in favor of Hagel two years ago, but returned to him after Hagel offered his resignation under pressure in November.