Carnot’s word is “fight to the last.” Sir John Jones says the commander has no right to provoke further carnage when resistance is hopeless. The question of course is, When is resistance hopeless? Sir John Jones’s reputation leaves little doubt that if he had been commanding a fortress on British soil he would not have thought resistance hopeless as long as there was anything whatever left to defend. The reason why these two men of similar temper are found in opposition is quite simple. When Carnot wrote, the French army occupied most of the important fortresses of Europe, and it was to the interest of the emperor that if attacked they should be held to the last moment, in order to cause the enemy as much delay and loss as possible. Jones, on the other hand, was one of the engineers who were engaged in besieging those fortresses, and his arguments were prompted by sympathy for his own countrymen whose lives were sacrificed by the prolongation of such resistance.
A century has passed since Carnot and Jones wrote, and the ideas in which they had been educated were those of the pre-Napoleonic era. In the 18th century fortresses were many, good roads few, and campaigns for the most part leisurely. To the European nations of that time, inheritors of a perennial state of war, the idea of concentrating the national resources on a short and decisive campaign had not occurred. The “knock-out blow” had not been invented. All these conditions are now so changed that new standards must be and indeed have been set up, both for the defence of places and the general employment of fortification.
As regards the conduct of the defence, the massacre of a garrison as a penalty for holding out too long would meet with no sympathy in the present day. On the other hand, the issue of modern wars is worked out so rapidly that if a fortress is well defended, with the advantage of the present weapons, there is always a chance of holding out till the close of the war. If the place is worth holding, it should as a rule be held to the bitter end on the chance of a favourable turn in affairs; moreover, the maintenance of an important siege under modern conditions imposes a severe strain on the enemy and immobilizes a large number of his troops.
In concluding this article some elementary considerations in connexion with the use of permanent defences may be noticed, though the general question of strategic fortification is outside its scope. The objects of fortification differ, Permanent defences. as has been shown, from age to age. In former times a peaceful people exposed to the raids of piratical Norsemen might find their refuge tower essential; later, a robber-baron might look on his castle as so much capital invested; a wealthy medieval town might prove the value of its walls more than once in a generation; a country without a standing army might gain time for preparation by means of fortresses barring the roads across the frontier. But how does the question stand to-day among European countries which can mobilize their full fighting strength at a few hours’ notice? It can only be answered when the circumstances of a particular country are examined.
If we assume such an impossible case as that of two nations of equal fighting strength and equal resources standing ready in arms to defend a common frontier, and that the theatre of war presents no difficulties on either side, The use and abuse of fortresses. then the use of permanent fortifications, merely as an adjunct to military strength, is wrong. Fortresses do not decide the issue of a campaign; they can only influence it. It is better, therefore, to put all the money the fortress would have cost, and all the man-power that its maintenance implies, into the increase and equipment of the active army. For the fate of the fortress must depend ultimately on the result of the operations of the active armies. Moreover, the very assumption that resources on both sides are equal means that the nation which has spent money on permanent fortifications will have the smaller active army, and therefore condemns itself beforehand to a defensive rôle.
This general negation is only useful as a corrective to the tendency to over-fortify, for such a case cannot occur. In practice there will always be occasion for some use of fortification. A mountain range may lend itself to an economical defence by a few men and some inexpensive barrier forts. A nation may have close to its frontier an important strategic centre, such as a railway junction, or a town of the first manufacturing importance, which must be protected. In such a case it may be necessary to guard against accidents by means of a fortress. Again, if one nation is admittedly slower in mobilization than the other, it may be desirable to guard one portion of the frontier by fortresses so as to force invasion into a district where concentration against it is easiest.
As for the defence of a capital, this cannot become necessary if it stands at a reasonable distance from the frontier until the active armies have arrived at some result. If the fighting strength of the country has been practically destroyed, it is not of much use to stand a siege in the capital. There can be but one end, and it is better, as business men say, to cut losses. If the fighting strength is not entirely destroyed and can be recruited within a reasonable time, say two or three months, then it appears that under modern conditions the capital might be held for that time by means of extemporized defences. The question is one that can only be decided by going into the circumstances of each particular case.
The case of a weak country with powerful and aggressive neighbours is in a different category. If she stands alone she will be eaten up in time, fortifications or no fortifications; but if she can reckon on assistance from outside, it may be worth while to expend most of the national resources on permanent defences.
These hypothetical cases have, however, no value, except as illustrations to the most elementary arguments. The actual problems that soldiers and statesmen have to consider are too complex to be dealt with in generalities, and no mere treatise can supply the place of knowledge, thought and practice.
Bibliography.—The more important works on the subject are: Dürer, Unterricht zur Befestigung (Nüremberg, 1527); Speckle, Architectur von Festungen (Strassburg, 1589); Fritach, L’Architecture mil. ou la f. nouvelle (Paris, 1637); Pagan, Les Fortif. (Paris, 1689); de Ville, Les Fortif. (Lyons, 1629); de Fer, Introduction à la fortification (Paris, 1723); B.F. de Belidor, Science des Ingénieurs, &c. (Paris, 1729); works of Coehoorn, Vauban, Montalembert, Cormontaingne; Mandar, De l’architecture des forteresses (Paris, 1801); Chasseloup-Laubat, Essais sur quelques parties de l’artil. et de la fortification (Milan, 1811); Carnot, Défense des places fortes (Paris, 1812); Jones, Journals of Sieges in Spain (3rd ed., London, 1846); T. Choumara, Mémoire sur la fortification (1847); A. von Zastrow, Geschichte der beständigen Befestigung (N.D., Fr. trans.); works of Sir C. Pasley; Noizet, Principes de fortif. (Paris, 1859); Dufour, De la fortif. permanente (Paris, 1850); E. Viollet le Duc, L’Architecture militaire au moyen âge (Paris, 1854); Cosseron de Villenoisy, Essai historique sur la fortification (Paris, 1869); works of Brialmont (q.v.); Delambre, La Fortification dans ses rapports avec la tactique et la stratégie (Paris, 1887); v. Sauer, Angriff und Verteidigung fester Plätze (Berlin, 1885); Schroeter, Die Festung in der heutigen Kriegführung (Berlin, 1898-1906); Baron E. v. Leithner, Die beständige Befestigung und der Festungskrieg (Vienna, 1894-1899); W. Stavenhagen, Grundriss der Befestigungslehre (Berlin, 1900-1909); Plessix and Legrand, Manuel complet de fortification (Paris, 1900, new edition 1909); Ritter v. Brunner, Die beständige Befestigung (Vienna, 1909), Die Feldbefestigung (Vienna, 1904); Rocchi, Traccia per lo studio della fortificazione permanente (Turin, 1902); Sir G.S. Clarke, Fortification (1907); V. Deguise, La Fortification permanente contemporaine (Brussels, 1908); Royal Military Academy, Text-book of Fortification, pt. ii. (London, 1893); British official Instruction in Military Engineering, pts. i., ii. and iv. (London, 1900-1908).