The placing of an army on a war footing and its transport to a frontier are political acts of the gravest moment. They are therefore usually controlled almost as much by political as by military considerations, and it is impossible rightly to appreciate them without taking into account the political circumstances by which they are affected. The influence of politics upon the two processes is however different. In regard to mobilization, which may be compared to a mechanical process, the statesman may urge its postponement or its execution by gradual instalments. In neither case is the essential nature of the operation changed, though the amount of friction involved may be increased. But the assembling of an army is the immediate preliminary to attack or defence, and the statesman's unwillingness to attack may affect the choice of time and place for the collection of the force available.
The King of Prussia was sincerely anxious to avoid a war, and until June 14 was determined not to take the initiative nor to agree to any measure which might savour of attack. He was with difficulty induced to consent to the successive stages of preparation. Not until the beginning of May, when the Austrian mobilization was far advanced and the transport to the frontiers impending, were the orders for the Prussian mobilization issued, and that not at once, but piecemeal between May 3 and May 12. The forces thus called out formed a total of 326,000 combatants, divided into nine army corps,[[2]] a reserve corps at Berlin,[[3]] the corps of occupation in Holstein, and the corps collected at Wetzlar from the Prussian garrisons withdrawn from fortresses of the German confederation. The arrangements made for the disposition of these forces between May 12 and June 22 form the basis of the subsequent success, and may perhaps best be described in the form of a series of problems and their solutions.
1. The first step of preparation for a war is the calculation of the force required.[[4]] In the case of our own small wars it is self-evident that such a calculation is necessary, and the campaign of 1882 in Egypt is an instance in which it was worked out to a nicety. It might seem equally a matter of course that when two Continental states go to war each of them will assume from the beginning that its whole available force will be employed. Yet instances are numerous in which campaigns have been lost mainly through neglect to work out this calculation. In 1859 the Austrians undertook with little more than half their army a war against the combined forces of France and Sardinia; in 1885 King Milan attacked the Bulgarians without calling out the whole of the Servian army. In both cases defeat was largely due to this initial error.
The basis of the calculation is furnished by an estimate of the force which will be at the disposal of the enemy. In 1866 the Prussian staff had to face the preliminary difficulty that it was uncertain even as late as May 8 which of the German states would be on the Prussian and which on the Austrian side. The least favourable assumption was made, and it was estimated that the hostile forces would be in North Germany 36,000, in South Germany 100,000, and in Saxony and Austria 264,000, making a total of 400,000 men.[[5]] There could be no doubt that Prussia must employ the whole of her available forces.
2. The next question was how to distribute the Prussian forces against these three sets of enemies. A proportionate division based on the estimate just given would have resulted in the employment of 215,000 men against Austria and Saxony, of 30,000 against North Germany, and of 80,000 against South Germany. The staff, however, expected that the South German forces would not be ready until a late stage of the war, and might in the first instance be neglected. Hanover and Hesse lying between the two halves of Prussia and separating Westphalia and Rhenish Prussia from the main body of the kingdom,[[6]] were more serious foes. It would be necessary to strike hard at them, if possible, before their preparations could be completed. But the fate of Prussia and of Germany really depended upon the issue of the conflict with Austria. If she were beaten here, Prussia would in any case be undone; if she were successful in this struggle, the minor states, even though not themselves beaten, must needs fall under her sway. It was decided to employ almost the whole army (eight and a half corps and the reserve corps, 278,000 men) against Austria and Saxony, and to meet the rest of the German enemies with a scratch army (48,000) made up of half the seventh corps and of the troops assembled in Holstein and at Wetzlar. This force was destined first of all to disarm Hesse and Hanover (capitulation of Langensalza June 29), and then to attack and defeat the South German contingents.
3. The next problem is the choice of the point or points at which the army is to be assembled for the purpose of beginning the operations. This is the first act of generalship in the campaign, and a mistake here is usually the prelude of misfortune. Every general wishes, if possible, to meet with his whole force the divided forces of the enemy, and therefore his first thought is to assemble his army at one place, or at least to collect it so that all its parts may unite for battle.
Sketch Map 2—PRUSSIA in 1866
The Prussian army, if assembled in Upper Silesia, would be at the point of Prussia nearest to the Austrian capital; if assembled at Görlitz,[[7]] it would interpose between Berlin or Breslau and an Austrian army approaching from Bohemia. These were, therefore, the most favourable points of assembly, the one for attack and the other for defence. But the position in Silesia would lose much of its value unless it were intended, as soon as the army should be ready, to march on Vienna; and this course in the middle of May was, to the king's mind, inadmissible. There was, however, a second quite unanswerable argument against assembling the whole army at either place. The movement could not be carried out in a reasonable time. To march to either district from the distant provinces would have been an affair of many weeks, and the concentration would run the risk of being too late. The difficulty could not be overcome by the use of the railways. To move a whole army corps by a single railway required, according to the nature of the line, irrespective of the distance, from nine to twelve days. But for the transport to Upper Silesia only one, and for that to Görlitz only two, through railways were available, so that a very long time would be required to move the whole army by rail to either point. Moreover, neither of the districts in question is so fertile as to be able to feed a large army for more than a few days. As the king was determined not to fight, if fighting could be avoided, it might become necessary to keep the army waiting for some weeks after its concentration. This would be to starve it before a shot had been fired. Thus it was impracticable in the political circumstances to collect all the nine corps into one army, either for offence or defence. Separate armies had to be formed, and considerations of defence to prevail. The principal centres of concentration were fixed in the neighbourhood of Görlitz and of Schweidnitz, points on the lines of an Austrian advance towards Berlin and Breslau respectively from Northern Bohemia, where at this time (the middle of May) the Austrian army was believed to be assembling.