Racially tinged discord flared before Memphis' City Council as it voted to change park names with Confederate-linked names.
"Our military is more capable, and our force is more powerful, when we use all of the great diverse strengths of the American people," Panetta said.
Looking to historians for guidance in taking full advantage of occasion to set more optimistic tone for next four years.
Obama plans to use a Bible that belonged to the Rev. Martin Luther King Jr. as he takes his oath of office on the holiday honoring the slain icon.
Dr. King discusses the importance of the civil rights movement.