The Indirect Approach.—Thus we see that the mere fact of marching indirectly towards the enemy and on to the rear of his dispositions does not constitute a strategic indirect approach. Strategic art is not so simple. Such an approach may start by being indirect in relation to the enemy's front, but by the very directness of its progress towards his rear may allow him to change his dispositions so that it soon becomes a direct approach to his new front.
Because of the risk that the enemy may achieve such a change of front, it is usual, and usually necessary, for the dislocating move to be preceded by a move or moves, which can perhaps best be classified under the term "distract" in its literal sense of "to draw asunder." The purpose of this "distraction" is to deprive the enemy of his freedom of action, and it should operate in both the physical and psychological spheres. In the physical, by causing a distension of his forces or their diversion to unprofitable ends, so that they are too widely distributed and too committed else where to have the power of interfering with one's own decisively intended move. In the psychological sphere, the same effect is sought by playing upon the fears of, and by deceiving the opposing command. "Stonewall" Jackson realized this when he framed his strategical motto—"Mystify, mislead, and surprise." For to mys tify and to mislead constitutes "distraction," and surprise is the essential cause of "dislocation." And it is through the "distrac tion" of the commander's mind that the distraction of his forces follows. The loss of his freedom of action is the sequel to the loss of his freedom of conception.
Realizing how the psychological permeates and dominates the physical sphere, we begin to see what Napoleon meant by his famous dictum that "the moral is to the physical as three to one." This realization warns us, too, of the fallacy and shallowness of attempting to analyze and theorize about strategy in terms of mathematics. To treat it quantitatively, as if the issue turned merely on a superior concentration of force at a selected place is as faulty as to treat it geometrically as a question of lines and angles. Yet voluminous works have been devoted to a "com partmented" analysis of strategy under such headings as "the rela tion between the fronts of opposing armies and their respective lines of communication with their base," "Case of both armies forming on a front parallel to the line of communication with the base," and so on.
But a prolonged abstract analysis of psychological strategy would be wearisome without being helpful, for it is only possible to probe into the mind of a commander through the medium of historical examples. Lack of space here forbids even an outline of strategical history, and all that can be done is to give some indication of the examples most worthy of study and of the main developments in methods and conditions. But while the means of strategy change and develop, so that there is progress in the physical sphere, in the psychological sphere it is no more possible to talk of the evolution of strategy than it is to talk of the evolution of painting. The history of strategy is an arid waste— of reliance upon sheer force—illumined by the genius of occasional masters for playing upon the mind of their opponents.
In ancient warfare the absence of "lines of communication" limited the scope for strategy. Hence the use of the indirect approach is mainly seen in grand strategy or in the immediate prelude to a battle. In one case, however, the scale and range of the effort compelled the adoption of what was virtually a "line of communication" for its maintenance. This was in the first "Great War" of European history—the Great Persian War. The indirect approach which dislocated the Persian invasion of 481 B.C. was made by sea, and it is noteworthy that the power of strategic mobility at sea was realized much earlier than on land. In land warfare true strategy, and the indirect approach, are first manifested when Thebes challenged Sparta for the supremacy which she had wrested from Athens. Epaminondas might well be called the "father of strategy" was it not that the term suggests the idea of subsequent evolution. Certainly in strategy as in tactics he was the first master, and the operations which preceded the battle of Mantineia reveal the ripening of his art. Until his final campaigns on the Indian border, the strategy of Alexander is devoid of subtlety. The cause would appear to be, first, that in the youthful Alexander, bred to kingship and triumph, there was more of the Homeric hero than in the other great cap tains of history; and, still more perhaps, that he had such justifi able confidence in the superiority of his instrument and his own battle-handling of it that he felt no need to dislocate prepara torily his adversaries' strategic balance. His lessons for posterity lie at the two poles—war-policy and tactics.