On September 1, 1975, James was promoted to the four-star rank of general (O-10), becoming the highest ranking African-American in the history of the United States military to that date. He was assigned as commander in chief of NORAD/ADCOM at Peterson Air Force Base, Colorado. In these dual capacities he had operational command of all United States and Canadian strategic aerospace defense forces. On December 6, 1977, he assumed duty as special assistant to the Chief of Staff, U.S. Air Force.