President Obama officially nominated former Pentagon official Ashton Carter as his pick for defense secretary today, replacing Chuck Hagel. Carter, who has a degree in physics from Yale, has served in a number of roles at the Defense Department, mostly focusing on things like budget and military acquisitions. Carter called the nomination an "honor and a privilege"
The White House had wanted Hagel to hold off on publicizing his departure until Obama had picked his successor, and Hagel refused, CNN reported Tuesday. But on Thursday, Hagel waved off discord with the president, saying there were "no major differences" that led to his resignation. --Peter Weber