The German doctrine of the motorized arm is in keeping with the classical conception of the aim of war as defined by Clausewitz a century ago, and reaffirmed by the masters of German strategical concepts--von Moltke, Bernhardi, and von Schlieffen--namely, the destruction of the enemy's armies. This destruction is achieved only after the dissolution of the "animistic cohesion" of the adversary, to use the expression of Ludendorff. In the pursuit of this objective, the blitzkrieg utilizes the new methods placed at its disposal by modern techniques and fully exploits their potentialities. Ultrarapid communications, photography, moving pictures, explosives, and engines both on the ground and in the air are thus militarized far more thoroughly than were the railways by the first von Moltke.
Therefore, from both the strategical and tactical points of view, the question for the different echelons of large as well as of small combat units is to determine the most effective means of bringing about the psychological and material disintegration of the adversary.
German strategists consider the battle of Cannae the supreme example of perfect victory; in that engagement the Carthaginians, under Hannibal, enveloped and completely annihilated the Roman Army. Being skilled in military psychology, the German generals correctly estimated the decisive effect that could be produced on the morale of the fighting troops by the sudden appearance of enemy forces on their flanks or rear.
In modern warfare this maneuver is even more effective than at any time in the past. When moral forces alone were the predominant factors in the struggle, and only rudimentary matériel was required, seasoned troops could risk fighting on a reversed front. Today, fighting armies consume a prodigious quantity of munitions, food supplies, equipment, and combat matériel. To insure a continuous flow of these necessities, the armies must constitute a homogeneous and welded whole with their rear supply units. Hence an army which is obliged to remain on the defensive because of numerical inferiority is absolutely required to constitute and maintain a coherent front. Weak places always represent a grave danger, especially if they become breaches, and all the more so if they give the enemy a chance to cut the lines of communication so indispensable to the life and action of the combatant elements.
The problem facing the assailant is the destruction of the defense. He should accomplish his purpose by an envelopment or a penetration at a judiciously selected point of the front.
For the last hundred years, since the time of Napoleon, an equilibrium has been maintained in Europe between the political powers and their military establishments. The opposing armies had approximately equal means, and attempts at break-through failed, as in the first World War, because there were adequate weapons available for the defense. As a rule, the decision was obtained on the flanks.
The day on which the Third Reich sacrificed the entire economic life of the country to the preparation for a long-premeditated aggression, and constituted such an offensive force that it no longer needed to fear any effective counteraction on the part of the chosen victim, a break-through became not only possible but preferable. However extended it might be, any attempted German envelopment on the right was sure to encounter an Allied front.
Thus the German outflanking doctrine, inaugurated by Frederick II, and applied with such success by his disciples in 1870, progressively made way for the doctrine of the "break-through" and "interior outflanking."
The mechanism of the penetration and subsequent interior outflanking may be summarized as it appeared during the campaign in the West:
1. First, cause the extension, if possible even the overextension, of the opposing force by the threat of a large-scale envelopment. Cause the absorption of reserves and particularly the most mobile reserves of the adversary on the threatened wings (previous attack on Norway and attack on Holland by von Kuechler's 18th Army and the 9th Armored Division).
2. Then attack at a suitable central point chosen for its strategical importance or its tactical vulnerability. Form a mass at this point and assault with the maximum of available means, without regard to the inevitable losses (as in the attack on Sedan by the von Rundstedt Group of Armies and the von Kleist Armored Groupment; Sedan was the "hinge" of the French set-up and whoever held it was master of the shortest roads to Paris or the English Channel).
3. As soon as the break-through is effected, exploit it immediately with the armored forces acting in close liaison with the air reconnaissance and the combat forces.
Assign them objectives in depth that will coincide as far as possible with the sensitive points indispensable to the material life of the enemy army (important crossroads, regulating stations, and depots of every kind), and insist on speed.
Do not slow down the armored forces by requiring them to widen the breach. This role is reserved for the infantry of the normal divisions following after the assault of the fast-moving units. As a matter of fact, armor greatly diminishes the vulnerability of the exploitation forces initially confined in a narrow breach.
Also, do not require the armored units to maintain approximate alinement with other fast-moving units advancing to the right or left on parallel axes; on the contrary, demand that they push forward, seeking the point of least resistance without wasting time at the defensive areas they may encounter.
4. The enemy may endeavor to parry this form of attack by breaking off the battle and reconstituting a new front farther to the rear. Consequently, in order to prevent the enemy from reorganizing such a front, a drive should be made to gain control of important crossroads or bridges over rivers along which it might be organized, and to reach before the enemy does the last obstacles beyond which no maneuvering is possible (for example, the English Channel after Sedan).
Simultaneously, have the entire effort of the aviation concentrated on the assembly areas of reserves and on vital points of the communication system used for the movement of reserves.
5. In spite of the boldness of such a race forward, always insure protection against an eventual counterattack on one's flanks and rear. (Consider the constant flank protection of the von Kleist Groupment in its break-through toward the English Channel: one armored division maintained protection to the south against counterattack by the French, and was progressively replaced in this mission by normal infantry divisions as these came up. Compare this maneuver with the attack of the 4th Armored Division on Le Quesnoy, May 21, to protect the Hoth Groupment then engaged toward Arras in the north.)
6. As soon as the attack has been made in sufficient depth to effect the disruption of enemy formations and the definite isolation of different hostile masses, a defensive attitude should be maintained toward the masses temporarily neglected. This will be done by resisting on carefully selected positions in support of the bridgeheads necessary for the ensuing phases of assault (defensive attitude on the Somme and the Aisne of the German 12th and 16th Armies before the attack of June 5 while the armored groupments continued to the English Channel and reorganized for the drive to the south).
7. Once the objective is chosen, bring all the offensive action to bear upon it; envelope its flank and rear by means of rapid forces (von Kleist Groupment at Boulogne and Calais, May 23: the Germans, having defined the Channel ports as their objective, rushed the von Kleist Armored Groupment towar4l them leaving the following infantry to hold the Somme front on their left flank until the Groupment could be reorganized for the drive to the south).
8. Whenever possible, insure the early relief of the mobile elements which are always needed farther on. (Relief of the 10th Armored Division along the Somme by the infantry of the following armies. Relief of the von Kleist and Hoth Groupments by the 4th Army front of Dunkirk and Lille, May 29, so that they could be reorganized for the drive to the south.)
9. If the enemy offers a strong degree of resistance in a front on which he has massed a dense concentration, then effect anew its break-up and envelopment by making new break-throughs (Cassel and the Mont-des-Cats, during the battle of Flanders; fast-moving divisions were sent as far forward as possible between the retreating French armies after June 8).
10. Thus reduce the sections of the enemy Army one after the other, or simultaneously, according to the means available (group of Allied Armies of the North, then the Armies of the Weygand position, then the Armies of the Maginot Line).
This analysis shows clearly the role devolving upon the armored and motorized arm: to be the advance guard of normal divisions at the points of attack, and the instrument of exploitation and envelopment.
However, one should not lose sight of the fact that this arm--an expensive one, an arm of quality rather than of quantity, an arm subjected to an extreme attrition of man and matériel--cannot do everything. It must be constantly relieved by the armies composed of normal infantry divisions that endeavor to follow it closely. The close union effected between the armored units and these following armies must be emphasized. They are two echelons of one force and not two separate and independent armies. (Typical in this connection, during the first phase of the operations in the Ardennes, was the subordination of the von Kleist Groupment to the von Rundstedt Group of Armies, and that of the Hoth Armored Groupment to von Kluge's 4th Army.)
Furthermore, without denying the strategical effectiveness of the blitzkrieg, it is well to recall at the end of this analysis that a blitzkrieg is feasible only when the enemy does not possess a striking force of equal power. It implies at the very outset a considerable superiority, of the means of attack over those of the defense. It requires uninterrupted supplying; otherwise the rapidity of its advance, an indispensable condition for its success, will be slowed down. In this respect, the use of airplanes for supplying armored units with ammunition and fuel cannot be considered wasteful. Also, it is apparent that a success comparable to that of the German campaign in the West could not be expected in a theater of operations not provided with such a dense road system, nor with such large resources as would permit the invader to live almost entirely off the country.
Finally, if failure is to be avoided, the blitzkrieg demands a long and extraordinarily minute preparation of the contemplated operations. The conduct and especially the supplying of motorized warfare limit the possibility of improvisation. The many details of the indispensable plans for the development of the "drama" of a blitzkrieg imply a long period in which the plan may be secretly prepared before the country to be attacked becomes alarmed.