As a main characteristic of the new structure, NATO decided that its headquarters would be integrated, multinationally and operationally during peacetime. This was a totally new concept. While Alliance decisions were to be taken at the multi-national level, where individual nations would keep their sovereignty, the executive military organisation adopted the principle of "one man's" leadership. Personnel assigned by the nations to allied commands were to be fully subordinated to their allied commanders assuming, therefore, an "international status." As far as national forces were concerned, each nation would decide which to assign to NATO, which to define "earmarked" to NATO and which to keep permanently for national tasks.
The Supreme Headquarters Allied Powers Europe (SHAPE) was formally activated near Paris on 2 April 1951. At the same time the staff and facilities of the Western (European) Union Commanders-in-Chief Committee were placed at SACEUR's disposal. Fourteen to 15 divisions and fewer than 1,000 operational aircraft were available to this command, to deter aggression by the 210 Soviet divisions and their more than adequate air arm.
The next step urgently needed was the creation of regional organisations better able to develop local contingency plans, even if no military forces were at that time assigned to NATO. In the same year, the three European Regional Planning Groups shifted their responsibilities to newly established major subordinate commands: Allied Forces Southern Europe (AFSOUTH), Allied Forces Central Europe (AFCENT) and Allied Forces Northern Europe (AFNORTH). Respectively, these would have been commanded by U.S., French and British officers.
NATO planners, from the beginning, had no doubts that adequate attention was to be paid to the southern flank; not only to comply with the pledge to defend the southern member countries, but also to protect the vital sea line of communication upon which Europe has always depended. In addition, the southern flank was a barrier against Soviet expansionism towards Africa, the Middle East and the Persian Gulf.
European interests in Northern Africa and the Middle East were particularly strong. The United States and Canada also were dependent upon the Mediterranean for shipping from the Indian Ocean, the Far East and, particularly, for the oil traffic from the Persian Gulf. Some of the Allies had a military presence in Morocco, Tunisia, Algeria, Libya and Egypt. However, the area of application of the Atlantic Treaty has never included the North African littoral. The control and defence of the Algerian Department of France, considered French homeland until its independence in 1962, remained a responsibility of France. There were therefore plenty of reasons for creating a specific command to be in charge of such a complex and different area.