On War

by Carl von Clausewitz

One single moderate march does not wear down the instrument, but a succession of even moderate marches is certain to tell upon it, and a succession of severe ones will, of course, do so much sooner.

At the actual scene of war, want of food and shelter, bad broken-up roads, and the necessity of being in a perpetual state of readiness for battle, are causes of an excessive strain upon our means, by which men, cattle, carriages of every description as well as clothing are ruined.

It is commonly said that a long rest does not suit the physical health of an army; that at such a time there is more sickness than during moderate activity. No doubt sickness will and does occur if soldiers are packed too close in confined quarters; but the same thing would occur if these were quarters taken up on the march, and the want of air and exercise can never be the cause of such sicknesses, as it is so easy to give the soldier both by means of his exercises.

Only think for a moment, when the organism of a human being is in a disordered and fainting state, what a difference it must make to him whether he falls sick in a house or is seized in the middle of a high road, up to his knees in mud, under torrents of rain, and loaded with a knapsack on his back; even if he is in a camp he can soon be sent to the next village, and will not be entirely without medical assistance, whilst on a march he must be for hours without any assistance, and then be made to drag himself along for miles as a straggler. How many trifling illnesses by that means become serious, how many serious ones become mortal. Let us consider how an ordinary march in the dust, and under the burning rays of a summer sun may produce the most excessive heat, in which state, suffering from intolerable thirst, the soldier then rushes to the fresh spring of water, to bring back for himself sickness and death.

It is not our object by these reflections to recommend less activity in war; the instrument is there for use, and if the use wears away the instrument that is only in the natural order of things; we only wish to see every thing put in its right place, and to oppose that theoretical bombast according to which the most astonishing surprises the most rapid movements, the most incessant activity cost nothing, and are painted as rich mines which the indolence of the general leaves unworked. It is very much the same with these mines as with those from which gold and silver are obtained; nothing is seen but the produce, and no one asks about the value of the work which has brought this produce to light.

On long marches outside a theatre of war, the conditions under which the march is made are no doubt usually easier, and the daily losses smaller, but on that account men with the slightest sickness are generally lost to the army for some time, as it is difficult for convalescents to overtake an army constantly advancing.

Amongst the cavalry the number of lame horses and horses with sore backs rises in an increasing ratio, and amongst the carriages many break down or require repair. It never fails, therefore, that at the end of a march of 100 miles or more, an army arrives much weakened, particularly as regards its cavalry and train.

If such marches are necessary on the theatre of war, that is under the eyes of the enemy, then that disadvantage is added to the other, and from the two combined the losses with large masses of troops, and under conditions otherwise unfavourable may amount to something incredible.

Only a couple of examples in order to illustrate our ideas.

When Buonaparte crossed the Niemen on 24th June, 1812, the enormous centre of his army with which he subsequently marched against Moscow numbered 301,000 men. At Smolensk, on the 15th August, he detached 13,500, leaving, it is to be supposed, 287,500. The actual state of his army however at that date was only 182,000; he had therefore lost 105,000.(*) Bearing in mind that up to that time only two engagements to speak of had taken place, one between Davoust and Bragathion, the other between Murat and Tolstoy-Osterman, we may put down the losses of the French army in action at 10,000 men at most, and therefore the losses in sick and stragglers within fifty-two days on a march of about seventy miles direct to his front, amounted to 95,000, that is a third part of the whole army.