Before the D-Day invasion in 1944, Harris was ordered to switch targets for the French railway network, a switch he protested against because he felt it compromised the pressure being applied to German industry and using Bomber Command for a purpose it was not designed or suited for. By September the Allied forces were well inland; at the Quebec Conference it was agreed that the Chief of the Air Staff, Royal Air Force (Portal), and the Commanding General, U.S. Army Air Forces (Arnold), should exercise control of all strategic bomber forces in Europe. Harris received a new directive to ensure continuation of a broad strategic bombing programme as well as adequate bomber support for General Eisenhower's ground operations. The mission of the strategic air forces remained "the progressive destruction and dislocation of the German military, industrial and economic systems and the direct support of Land and Naval forces".