During World War II, most officers were White, and most Black troops still served only as truck drivers and as stevedores. The Red Ball Express, which was instrumental in facilitating the rapid advance of allied forces across France after D-Day, was operated almost exclusively by African American truck drivers. In the midst of the Battle of the Bulge in late 1944, General Dwight D. Eisenhower was severely short of replacement troops for existing military units, all of which were totally white in composition, so he made the decision to allow African American soldiers to join the White military units to fight in combat for the first time —the first step toward a desegregated United States military. Eisenhower's decision in this case was strongly opposed by his own army chief of staff, Lieutenant General Walter Bedell Smith, who was outraged by the decision, and said that the American public would take offense with the integration of the military units.