During the past decade and a half, armies have been progressively striving to capitalize the machinery of movement, to integrate the armored land cruiser and the motored transport vehicle into a mobile striking force of high military potential. Out of these studies, experimentation, and development have slowly emerged doctrines that promise to profoundly influence the conduct of so much of the next general war as will be fought on land.
The accelerated tempo of movement to which every important army is today attempting to accommodate itself is an outstanding characteristic of modern life—one so implicit in the present era of civilization as to profoundly influence the arts of war as well as those of peace. Peoples accustomed to air travel and impatient of 40-mile speed on highways have forced, for better or worse, an acceleration of thought upon their military leaders. The nation on wheels is no longer content to have its army afoot or even on horseback.
Suppose armies take to wheels, much as navies, years ago, took to steam. (The parallel is by no means exact, yet it will serve.) Then the land forces, or at least so much of them as are rolling, must thumb back some pages of military history to relearn the lessons of rapid maneuver. Or they may regard the mobility of even Genghis Khan, Tamerlane, and Alexander as totally outmoded, and seek to apply directly certain principles of naval tactics to land warfare.
For the proponents of extreme mechanization foresee fleets of machines swiftly traversing the countryside, seeking or evading combat, striking where victory is promised, imposing constantly over wide areas the threat of a fleet in being, operating in general with much the influence of naval force.
Such a conception will of course never be completely realized. Movement cannot be capitalized in land operations to the extent it is habitually made use of in naval warfare. The space-annihilating elements of armies can be no more than echelons of the complete land force; yet if they lack ability in themselves to compel the final decision, they at least offer fascinating possibilities for contributing to that end.
History fails to disclose what race of warriors first curbed the fleetness of the horse and bound his limbs to the service of military movement. At least we are certain that, since the days of the Assyrian Empire, soldiers moved either afoot or by the aid of animals. This classical distinction of “marching troops” and “riding troops” has survived for not less than 40 centuries, and it is as vital today as ever, with the qualification that during the last quarter-century the development of the self-propelled vehicle has profoundly modified the manner in which the riding elements of military forces shall be transported.
The first appreciable use of motor trucks by the U. S. Army occurred no longer ago than 1916. During the same year, and in the same operations—the Mexican Punitive Expedition—the first airplane to be flown on a combatant mission in America, took the air. Almost simultaneously, in Europe, the first tank action was taking place. Thus 20 years ago appeared in rudimentary form the three elements that are now so confidently regarded as freeing armies from the tyranny of constrained movement.
Today the horse, which so recently as our own Spanish-American War was indispensable to military maneuver, has become almost entirely superannuated. In place of the draft animal we now have the motor carrier; instead of the cavalry charger, the mechanized fighting unit.
This dual groupment of vehicles has added two terms to military vocabularies, each with its specific technical connotation: motorized force and mechanized force.
By a motorized force is meant a body of troops which habitually uses motor vehicles for transporting both personnel and impedimenta. Not many years ago the automobile was regarded as a flexible supplement to the railroad for troop movement. Today motorized units may be and often are wholly independent of rail carriers.
Motorized forces have strategic mobility, considering that strategy relates to movements of troops prior to their commitment to action. But the motorized force leaves its vehicles as it nears the scene of battle, and attends to its fighting on foot, just as an over-seas expedition debarks from its troop transports preparatory to engaging the enemy.
A mechanized force, on the other hand, fights as it travels; in tanks, armored and combat cars, or—an extreme application of the term—in airplanes.
Hence mechanized forces possess tactical mobility. The term envisages the combination of fire and movement into a man- operated machine (a definition which serves equally well to describe the warship). It is used to herald the return of shock action to the battlefield from which it was frightened years ago by the rifle bullet.
So it is in combat that motorized and mechanized forces radically differ. On the approach march both may move at similar speeds, just as do troop transports and transport convoys on ocean voyages. But once within hostile artillery range, vehicles become an impediment to the motorized unit, so that they must be left in parks well beyond the enemy’s reach.
The mechanized unit, on the other hand, deploys at this point and proceeds confidently onward to fulfill its highest mission in direct contact with the hostile force. Its similarity in action to the naval fleet is here apparent.
But can the mechanized force effectively accomplish these two ends? Can it negotiate open terrain in deployed formations and then successfully attack? When it has satisfactorily demonstrated these abilities, the mechanized force will profoundly modify present conceptions of land warfare.
Protection, striking power, maneuverability—these are the characteristics which must blend into mechanized land forces. Their proper proportion is, in essence, but a variation of the naval problem of armor and armament versus speed. These requirements give rise on land just as they do at sea, to a variety of units, including continental prototypes of battleships, cruisers, and destroyers.
As to maneuverability, the first requirement of mechanized land force is that it shall be able to operate with ease in open country. The highway is here a strategical factor which has no tactical importance. The open road is merely an avenue for fast approach to the general vicinity of the battle area; once within the zone of hostile artillery fire, it becomes a liability.
So the mechanized force nears its objective across open country and so dispersed as to render ineffective the enemy’s long range interdicting and harassing fires.
At this stage of its action, the mechanized force is more concerned with static than with dynamic opposition. It must be able to overcome accidents of terrain and, to a limited degree at least, face such obstacles as land mines and emplaced barriers. It will be obliged to pass small streams, traverse hills and ravines, and detour wooded patches. Its vehicles must be able within themselves to overcome most of the inequalities of nature which are compensated for on a leveled highway. In a word, they must possess “land- worthiness.”
Of course it can never be expected that armored vehicles will traverse all types of open country. Just as rocky reefs and sandy bars are obstructions to navigation at sea, so must certain types of mountainous and desert country be eliminated from consideration by mechanized forces.
The British, who have developed armored vehicles probably further than any other foreign power, are inclined to group terrain into three general classes: that in general ideally suited by nature to combat vehicle action; that adapted only in part to such action; and that the predominant character of which is such as to preclude the use of automotive equipment other than on specially built roads.
This no doubt is a rational approach, since it immediately eliminates the impossible and delimits consideration to reasonably open country where accidents of terrain may be regarded as not insurmountable. Gently undulating plains and broad alluvial valleys form the natural arenas for the action of armored land forces; and such country is readily recognized as the stage setting of the really important land battles of history.
The scene of successful mechanized maneuver therefore is, in the nature of things, restricted to areas which are either, (1) wholly, or (2) partially, adapted by nature to ready passage.
For areas of the first category—say such country as the plains of eastern Wyoming—automotive science can today produce equipment substantially suitable to all the requirements of cross-country maneuver. Still further attention must be directed, however, to the problems presented by terrain of what might be termed medium ruggedness, such, for instance, as much of the country recently fought over in Ethiopia. Here carefully integrated reconnaissance, both aerial and terrestrial, can accomplish much in finding paths of relative ease; yet the ingenuity of the engineer must still be invoked for the design of vehicles to insure ambulation where these are wanting.
If there is any doubt as to the possibilities in this direction, one has only to visit the logging camps of the Northwest, where automotive equipment is regularly and efficiently employed, far from railroads and highways, to move great loads of lumber across most broken country.
The knee-action spring is one recent development that has done much to free the automobile from its dependence on the paved highway. This principle had already proved its value in tank design, where for some years it has served to endow that vehicle with a comparatively remarkable rate of speed. Improvements in 4-wheel-drive machines (first used by the Mexican Punitive Expedition) also contribute to the practicability of open- country maneuver. Dual tires are now in universal use; a new casing filler promises to make them free from both road and bullet punctures. Yet full-track and halftrack vehicles continue to compose the backbone of mechanized force, and further refinements in their design must be anticipated as the most important future contribution to the development of combat vehicles.
Once enabled to move freely over a wide variety of terrain, these vehicles must be capable of a cruising speed of up to 50 miles per hour on roads and not less than 10 miles per hour across country, these speeds of course varying, as with various units of the fleet, according to different tactical missions. The present development of motor design is such as to practically assure such open speeds as may be found tactically appropriate to these combat vehicles.
How then will the fleet of land vessels approach its objective, and what type of hostile formation will it engage? Partial answers to these questions may become evident from a more careful examination of the types of craft which compose the land fleet.
Besides the airplane, these include the tank, the armored (or combat) car, and the fast unarmored scout car. Each of these latter terms is now understood to designate a type of land vehicle as distinctive as is each component of the battle fleet.
Consider first the tank, the capital ship of the mechanized force.
This vehicle is today quite different from the crude contrivance that the British brought on the battlefield of the Somme in September, 1916. Not only have details of design been vastly improved; the conception of the tank’s station in the line of battle has also been radically modified.
Initially the tank appeared in response to the demand that the infantry soldier be protected in his advance from the murderous fire of machine guns. The best protection was obviously the crushing out of the machine gun itself, a purpose for which the tank soon proved its value. But throughout the war the tank, with rare exceptions, worked in close co-ordination with foot troops. It was much as though the use of ironclads during the Civil War had been limited to such operations as Porter’s against the Mississippi forts. The opportunity for independent missions never arose because maneuver space was never available, and particularly because a balanced fleet of mechanized vehicles to support and supplement the tank did not exist.
The conception of the tank as the capital ship of a land fleet is therefore a postwar theory that has never been subjected to the trial of battle. For this reason, experience as to the most effective tank speeds is wanting. So long as the tank acted in close conjunction with foot troops, its speed was a secondary consideration; but a wider radius of action and the presence of accompanying vehicles has necessitated a new balance between armament and horsepower.
These factors have directed thought toward two types of tanks for independent operations with mechanized force—one unit weighing 15 tons and another of half that weight, the heavier capable of in the neighborhood of 40 miles per hour on roads and at least 10 miles across open country.
The protection of these vehicles must be such as to ward off projectiles up to calibers of 37-mm. They can scarcely be made to withstand the direct impact of shell from the 75-mm. field gun, which are as distasteful to the mechanized force as are the emplaced guns of a well-organized harbor defense to naval force. But the tanks should have no fear of machine-gun or small caliber armor-piercing bullets.
Whether the two weights of tanks now under tentative consideration are the most practicable may have to await the outcome of battle experience. At least the need for two distinct types is in close parallel to the naval requirement for battleships and battle cruisers, each having similar striking power, one sacrificing and the other gaining speed at the expense of armor.
The combat car occupies, in the line-up of mechanized vehicles, a position somewhat analogous to that of the cruiser. Actually it is a lightly-armored, high-speed tank, conceived to function with cavalry much as the early tanks were designed to accompany infantry. This hybrid arrangement may or may not survive the impact of war, depending on the future efficacy of horse cavalry, but at least the importance of the 8,000-ton cruiser with the fleet suggests the possible employment with armored land force of the vehicle now known as the combat car.
The armored car is another distinctive vehicle, similar in fundamental design to the destroyer. It is a tired car, in contrast to tanks and combat cars which employ full tracks. The most favored design at present includes a weight of 5 tons, carried by 6 wheels at a road speed of some 60 miles, with good cross-country maneuverability. The armor is relatively light, capable of countering the rifle bullet but vulnerable to cannon fire.
The scout car is the pawn of the mechanized force. It consists of an unprotected chassis normally carrying two passengers. Its peculiar characteristics are speed and lightness. These requirements appear to be met in the British service by the Austin car, although opinion on this side of the Atlantic inclines toward a more sturdy design. In any event, the scout car must be able to maneuver quickly across open country, extricate itself when stuck, act as an outer screen, and not infrequently offer itself as a sacrifice.
Here we have, then, the salient outlines of the mechanized force as it appears today across the military horizon. Starting with the path-finding scout cars to reconnoiter and develop hostile dispositions, the armored cars follow not far behind with the dual missions of breaking up incipient opposition and covering the advance of the tanks, while the latter approach to close the attack. Add observation airplanes, from one of which the force commander may direct the operation by radio telephone, and it is possible to visualize a military fleet which fundamentally is not dissimilar to its high seas model.
There is as yet, however, little basis for supposing that the highest mission of mechanized units is in seeking and destroying corresponding units of the enemy. The clash of tank against tank, while it may eventualize, appears at present to offer less promise than does the attack of lightly organized positions, the seizure of commanding terrain features, disruption of lines of communication, and similar actions against elements possessing little or no mobility. For such actions the mechanized force, properly organized and handled, possesses advantages corresponding to those of battleships when engaging merchant vessels.
While an important purpose of mechanized force is to seize objectives of strategic worth, these it is incapable of holding for long against extended counterattack. This task is therefore delegated to motorized force, which moves quickly to the scene and furnishes the personnel needed for the organization of the position. Then, moving more slowly as befits dismounted troops, will come the backbone of the Army, the foot soldier, who will relieve the motorized force, consolidate the position, and prepare to hold it against all comers.
This, briefly, is a conception of the opening scenes of the next war as visualized by those who insist that the utmost military use must be made of modern automotive transportation. And, if their predictions are confirmed, if the seize-hold- occupy theory can be applied initially on a large enough scale and over a wide enough area, then the first act will include the crisis of the show, which will be followed shortly by a denouement representing the opponent’s capitulation.
For such an echelonment of force the Army of the United States is well suited. The regular Army can supply the mechanized or initial striking force. The National Guard, the great reservoir of partially trained personnel, can provide the motorized force. And the remaining man power of the nation, the National Army, may be expected to furnish the supporting divisions organized along lines essentially similar to those in effect during the World War.