Elements of Military Art and Science / Or, Course Of Instruction In Strategy, Fortification, Tactics Of Battles, &C.; Embracing The Duties Of Staff, Infantry, Cavalry, Artillery, And Engineers; Adapted To The Use Of Volunteers And Militia; Third Edition; With Critical Notes On The Mexican And Crimean Wars.

by H. W. Halleck

"The possession of strategic points," says the Archduke Charles, "is decisive in military operations; and the most efficacious means should, therefore, be employed to defend points whose preservation is the country's safeguard. This object is accomplished by fortifications, inasmuch as they can resist, for a given time, with a small number of troops, every effort of a much larger force; fortifications should, therefore, be regarded as the basis of a good system of defence." "It should be a maxim of state policy in every country, to fortify, in time of peace, all such points, and to arrange them with great care, so that they can be defended by a small number of troops. For the enemy, knowing the difficulty of getting possession of these works, will look twice before he involves himself in a war." "Establishments which can secure strategic advantages are not the works of a moment; they require time and labor. He who has the direction of the military forces of a state, should, in time of peace, prepare for war." "The proper application or neglect of these principles will decide the safety or the ruin of the state." "Fortifications arrest the enemy in the pursuit of his object, and direct his movements on less important points;—he must either force these fortified lines, or else hazard enterprises upon lines which offer only disadvantages. In fine, a country secured by a system of defences truly strategic, has no cause to fear either the invasion or the yoke of the enemy; for he can advance to the interior of the country only through great trouble and ruinous efforts. Of course, lines of fortifications thus arranged cannot shelter a state against all reverses; but these reverses will not, in this case, be attended by total ruin; for they cannot take from the state the means nor the time for collecting new forces; nor can they ever reduce it to the cruel alternative of submission or destruction."

"Fortifications," says Jomini, "fulfil two objects of capital importance,—1st. The protection of the frontiers; and 2d. Assisting the operations of the army in the field." "Every part of the frontiers of a state should be secured by one or two great places of refuge, secondary places, and even small posts for facilitating the active operations of the armies. Cities girt with walls and slight ditches may often be of great utility in the interior of a country, as places of deposit, where stores, magazines, hospitals, &c., may be sheltered from the incursions of the enemy's light troops. These works are more especially valuable where such stores, in order not to weaken the regular army by detachments, are intrusted to the care of raw and militia forces." It is not supposed that any system of fortifications can hermetically close a frontier; "but, although they of themselves can rarely present an absolute obstacle to the advance of the hostile army, yet it is indisputable that they straiten its movements, change the direction of its marches, and force it into detachments; while, on the contrary, they afford all the opposite advantages to the defensive army; they protect its marches, favor its debouches, cover its magazines, its flanks, and its movements, and finally furnish it with a place of refuge in time of need."

These opinions were uttered, be it remembered, long since the period at which modern military quacks date the downfall of fortifications as inland defences, by men, too, who were not engineers, and consequently had no professional predilections in favor of fortifications. The Archduke Charles, as a general, knew no rival but Napoleon, and General Jomini is universally regarded as the first military historian of the age. The truth of their remarks on fortifications is most fully confirmed by the military histories of Germany and France.

For a long period previous to the Thirty Years' War, its strong castles and fortified cities secured the German empire from attacks from abroad, except on its extensive frontier, which was frequently assailed, but no enemy was able to penetrate to the interior till a want of union among its own princes opened its strongholds to the Swedish conqueror; nor then, did the cautious Gustavus Adolphus venture far into its territories till he had obtained possession of all the military works that might endanger his retreat.

Again, in the Seven Years' War, when the French neglected to secure their foothold in Germany, by placing in a state of defence the fortifications that fell into their power, the first defeat rendered their ground untenable, and threw them from the Elbe back upon the Rhine and the Mayne. They afterwards took the precaution to fortify their positions, and to secure their magazines under shelter of strong places, and, consequently, were enabled to maintain themselves in the hostile country till the end of the war, notwithstanding the inefficiency of their generals, the great reverses they sustained in the field, the skill and perseverance of the enemy they were contending with, and the weak and vacillating character of the cabinet that directed them.

But this system of defence was not so carefully maintained in the latter part of the eighteenth century, for at the beginning of the French Revolution, says Jomini, "Germany had too few fortifications; they were generally of a poor character, and improperly located." France, on the contrary, was well fortified: and although without armies, and torn in pieces by domestic factions, (we here use the language of the Archduke,) "she sustained herself against all Europe; and this was because her government, since the reign of Louis XIII., had continually labored to put her frontiers into a defensive condition agreeably to the principles of strategy; starting from such a system for a basis, she subdued every country on the continent that was not thus fortified; and this reason alone will explain how her generals sometimes succeeded in destroying an army, and even an entire state, merely by a strategic success."

This may be illustrated by reference to particular campaigns. In 1792, when the Duke of Brunswick invaded France, she had no armies competent to her defence. Their numbers upon paper were somewhat formidable, it is true, but the license of the Revolution had so loosened the bonds of discipline as to effect an almost complete disorganization. "It seemed, at this period," says the historian, "as if the operations of the French generals were dependent upon the absence of their enemies: the moment they appeared, the operations were precipitately abandoned." But France had on her eastern frontier a triple line of good fortresses, although her miserable soldiery were incapable of properly defending them. The several works of the first and second lines fell, one after another, before the slow operations of a Prussian siege, and the Duke of Brunswick was already advancing upon the third, when Dumourier, with only twenty-five thousand men, threw himself into this line, and by a well-conducted war of positions, placing his raw and unsteady forces behind unassailable intrenchments, succeeded in repelling a disciplined army nearly four times as numerous as his own. Had no other obstacle than the French troops been interposed between Paris and the Prussians, all agree that France must have fallen.

In the campaign, of 1793, the French army in Flanders were beaten in almost every engagement, and their forces reduced to less than one half the number of the allies. The French general turned traitor to his country, and the National Guards deserted their colors and returned to France. The only hope of the Republicans, at this crisis, was Vauban's line of Flemish fortresses. These alone saved France. The strongholds of Lille, Condé, Valenciennes, Quesnoy, Landrecies, &c., held the Austrians in check till the French could raise new forces and reorganize their army. "The important breathing-time which the sieges of these fortresses," says an English historian, "afforded to the French, and the immense advantage which they derived from the new levies which they received, and fresh organization which they acquired during that important period, is a signal proof of the vital importance of fortresses in contributing to national defence. Napoleon has not hesitated to ascribe to the three months thus gained the salvation of France. It is to be constantly recollected that the Republican armies were then totally unable to keep the field; that behind the frontier fortresses there was neither a defensive position, nor a corps to reinforce them; and that if driven from their vicinity, the capital was taken and the war concluded."

In the following year, 1794, when France had completed her vast armaments, and, in her turn, had become the invading power, the enemy had no fortified towns to check the progress of the Republican armies; which, based on strong works of defence, in a few weeks overran Flanders, and drove the allies beyond the Rhine.

In the campaign of 1796, when the army of Moreau had been forced into a precipitate retreat by the admirable strategic operations of the Archduke Charles, the French forces owed their safety to the fortifications on the Rhine. These works arrested the enemy's pursuit and obliged him to resort to the tedious operations of sieges; and the reduction of the French advanced posts alone, Kehl and Huninguen, poorly as they were defended, employed all the resources of the Austrian army, and the skill of their engineers, from early in October till late in February. Kehl was at first assaulted by a force four times as numerous as the garrison; if the enemy had succeeded, he would have cut off Moreau's retreat, and destroyed his army. Fortunately the place was strong enough to resist all assaults; and Moreau, basing himself on the fortresses of Alsace, his right covered by Huninguen, Neuf-Brisach, and Béfort, and his left by the iron barrier of the Netherlands, effectually checked the waves of Austrian success.