Jomini pointed out (“Art de la Guerre,” Vol. ii., chap, vii.), and Clausewitz (“On War,” Book V., chap, v.) endorsed his view, that, for armies up to 100,000 strong, a Divisional organization was best. This strength represents five or six Divisions, and one or two Cavalry Divisions, which may therefore be considered as the maximum number which an army should comprise, if organized in Divisions only.
The advantages of the Army Corps organization of armies are that the Supreme Command is facilitated by there being fewer Units to direct, and that a few important Commanders can be better selected than a number. This organization also provides a large independent force, under a Senior Commander, available for any special mission. There were periods in the South African War when the temporary employment of several Divisions for a special purpose would have been more effective had they formed a permanent organization like an Army Corps, with its own Commander and Staff. At the same time it is undoubtedly true that, except when unavoidable, the addition of another step in the gradation of Command is undesirable for many reasons. It is wasteful in Staff; it tends to delay the transmission of Orders; and the large strength of the Army Corps gives their Commanders so much importance as to lead to considerable independence in their action, which may weaken the Supreme Command.
In large armies, however, organization by Army Corps is unavoidable. We therefore naturally find the forces of the great military powers of Europe—Germany, France, Russia, Austria, Italy—organized by Army Corps, while the forces of Turkey, Japan, Great Britain, and the smaller nations of Europe are organized by Divisions only. Switzerland is about to comply with this principle by transforming her present Army Corps into Divisions.
COMPOSITION OF AN ARMY CORPS
An Army Corps is generally composed, after the German model, of two Divisions, in spite of the ruling of Clausewitz that a division of any Unit into two parts is the worst possible. This is admitted by von der Golz in his “Nation in Arms,” and also by von Schellendorf in his “Duties of the General Staff.” Both agree that an Army Corps should have three Divisions, but think that it would be difficult to alter a system so deeply rooted in Germany. This criticism applies also to the bipartite organization of both Cavalry and Infantry Divisions and Brigades, which exists in most Continental armies. The Austrians have therefore adopted a Corps of three Divisions, and the Germans and French think of adding a Reserve Division to the two forming their Army Corps. To have three Divisions would undoubtedly strengthen the Command of the Corps, and, by reducing the number of Corps, facilitate that of the Army.
Besides the Infantry Divisions, there are other troops in an Army Corps—namely, Cavalry, Artillery, Engineers, and Administrative Services.
Corps Cavalry.—The French have a Brigade of Corps Cavalry, the Russians a Division. This is probably a better arrangement for providing “protective Cavalry” than to rely only on the few squadrons of Divisional Cavalry, as in Germany and Austria.
Corps Artillery.—German and Russian Army Corps have no Corps Artillery; other armies have two or more Brigades, organized in Regiments.
Heavy Artillery is likely to be allotted to Army Corps or perhaps to Armies, in foreign armies, as it is in England to the Division.