We have seen that the defensive in war generally—therefore, also, the strategic defensive—is no absolute state of expectancy and warding off, therefore no completely passive state, but that it is a relative state, and consequently impregnated more or less with offensive principles. In the same way the offensive is no homogeneous whole, but incessantly mixed up with the defensive. But there is this difference between the two, that a defensive, without an offensive return blow, cannot be conceived; that this return blow is a necessary constituent part of the defensive, whilst in the attack, the blow or act is in itself one complete idea. The defence in itself is not necessarily a part of the attack; but time and space, to which it is inseparably bound, import into it the defensive as a necessary evil. For in the first place, the attack cannot be continued uninterruptedly up to its conclusion, it must have stages of rest, and in these stages, when its action is neutralised, the state of defence steps in of itself; in the second place, the space which a military force, in its advance, leaves behind it, and which is essential to its existence, cannot always be covered by the attack itself, but must be specially protected.
The act of attack in war, but particularly in that branch which is called strategy, is therefore a perpetual alternating and combining of attack and defence; but the latter is not to be regarded as an effectual preparation for attack, as a means by which its force is heightened, that is to say, not as an active principle, but purely as a necessary evil; as the retarding weight arising from the specific gravity of the mass; it is its original sin, its seed of mortality. We say: a retarding weight, because if the defence does not contribute to strengthen the attack, it must tend to diminish its effect by the very loss of time which it represents. But now, may not this defensive