Ashton Carter Is Sworn In As Obama's 4th Defense Secretary

The cold and snow that walloped Washington overnight didn't stop Ashton Carter from reporting for work Tuesday. Carter was sworn in as the 25th U.S. Secretary of Defense after starting his day with meetings at the Pentagon.

Sworn in by Vice President Biden at the White House Tuesday, Carter formally replaces Chuck Hagel, becoming President Obama's fourth defense chief in the past six years.

Carter's debut at the Pentagon this morning was briefly interrupted when his wife, Stephanie, "slipped and fell on the icy pavement," the AP reports. "She laughed it off, and offici