Updated at 11:19 a.m.
President Obama named Ashton Carter, a former No. 2 Pentagon official, as his pick to succeed Defense Secretary Chuck Hagel.
Obama described Carter today as one of the "nation's foremost national security leaders."
"He was at the table in the situation room. He was by my side navigating complex security challenges that we were confronting," Obama said. I relied on his expertise and I relied on his judgment."
Carter called the nomination an "honor and a privilege."