The recent possibility, not yet entirely removed, of an invasion of Switzerland, has naturally revived the public interest not only concerning the defensive resources of the mountain Republic, but with regard to mountain warfare in general. People generally incline to regard Switzerland as impregnable, and think of an invading force as of those Roman gladiators whose Ave Caesar, morituri te salutant [Hail Caesar; those who are about to die salute you] has become so famous. We are reminded of Sempach and Morgarten, Murten and Granson  and we are told that it may he easy enough for a foreign army to get into Switzerland, but that, as the fool of Albert of Austria said, it will be difficult to get out again. Even military men will recite the names of a dozen mountain passes and defiles, where a handful of men might easily and successfully oppose a couple of thousands of the best soldiers. This traditional impregnability of the so-called mountain-fortress of Switzerland dates from the time of the wars with Austria and Burgundy, in the fourteenth and fifteenth centuries. in the former the armor-clad cavalry of the chivalry was the chief arm of the invaders; its strength lay in the irresistible charge against armies undefended by firearms. Now, this charge was impossible in a country like Switzerland, where cavalry, except of the lightest kind, and in small numbers, is even now useless. How much more so were the knights of the fourteenth century, encumbered with nearly a hundred weight of iron. They had to dismount and fight on foot; thus, their last remnant of mobility was lost; and the invaders were reduced to the defensive, and when caught in a defile were defenseless even against clubs and .sticks. During the Burgundian wars, infantry, armed with pikes, had become a more important portion of an army, and firearms had been introduced, but the infantry was still cramped by the weight of defensive armor, the cannon were heavy, and small arms clumsy and comparatively useless. The whole equipment of the troops was still so cumbersome as to unfit them completely for mountain warfare, and especially at a time when roads can scarcely he said to have existed. The consequence was that, as soon as these slow-moving armies were once entangled in difficult ground, they stuck fast, while the lightly-armed Swiss peasants were enabled to act on the offensive, to out-maneuver, to surround, and finally to defeat their opponents. For three centuries after the Burgundian wars, Switzerland was never seriously invaded. The tradition of Swiss invincibility grew venerable, until the French Revolution, an event which tore into shreds so many venerable traditions, destroyed this one too, at least for those acquainted with military history. Times had changed. The iron-clad cavalry and the heavy pikemen had passed away; tactics had been revolutionized a dozen times over; mobility was becoming the chief quality of armies; the line tactics of Marlborough, Eugene and Frederick the Great were being upset by the columns and skirmishers of the revolutionary armies; and from the day that General Bonaparte passed, in 1796, the Col di Cadibone, threw himself between the scattered Austrian and Sardinian columns, defeated them in front, while at the same time intercepting their retreat in the narrow valleys of the Maritime Alps, making the most of his opponents prisoners-from that day dates the new science of mountain warfare which has put an end to the impregnability of Switzerland. During the period of line tactics, which immediately preceded that of modern warfare, all difficult ground was studiously avoided by either adversary. The more level the plain, the better it was deemed for a battle-field, if it only afforded some obstacle to support one or both wings. But with the French revolutionary armies, a different system began. An obstacle before the front, covering ground for skirmishers, as well as for the reserves, was anxiously sought for in any defensive position. Difficult ground, upon the whole, was preferred by thein; their troops were far lighter in their movements; and their formations, extended order and columns, admitted not only of rapid movements in all directions, but even made it advantageous to them to profit by the shelter afforded by broken ground, at the same time that their opponents were quite lost in it. In fact, the. term impracticable ground was all but erased from the military terminology. The Swiss were made to feel this in 1798, when four French divisions, in spite of the obstinate resistance of part of the inhabitants, and of a three times repeated insurrection of the old forest cantons, made themselves masters of the country which, for the next three years, became one of the most important theaters of the war between the French Republic and the Coalition. How little the French were afraid of the inaccessible mountains and narrow gorges of Switzerland, they showed as early as March, 1798, when Mass na at once marched upon the roughest and most mountainous canton, the Grisons, then occupied by the Austrians. The latter held the upper valley of the Rhine. In concentric columns Mass na s troops marched into that valley through mountain passes hardly passable to horses, occupied all the outlets, and after a short resistance forced the Austrians to lay down their arms. The Austrians very soon profited by this lesson; under Hotze, a General who gained considerable proficiency in mountain warfare, they returned to the charge, repeated the same maneuver, and drove out the French. Then came the retreat of Mass na to the defensive position of Zurich, where he defeated Korsakoff s Russians, the invasion of Switzerland over the St. Gotthard by Souwaroff, his disastrous retreat, and finally another advance of the French through the Grisons into Tyrol, where Macdonald in the depth of winter passed over three mountain ridges then scarcely thought passable in single file. The great Napoleonic campaigns which then followed were fought out in the great river-basins of the Danube and the Po; the grand strategical conceptions on which they were based, all tending to cut off the hostile army from the center of its resources, to destroy that army, and then to occupy the center itself, implied a less intercepted ground and the concentration of masses for decisive battles not to be obtained in Alpine countries. But from the first Alpine campaign of Napoleon in 1796, and his march across the Julian Alps to Vienna in 1797, up to 1801, the whole history of warfare proves that Alpine ridges and valleys have completely lost their terror for modern troops; nor have the Alps ever since, up to 1815, offered any defensive positions worth speaking of to either France or the Coalition. When you pass through one of these deep ravines which wind up the roads that lead from the northern slope of the Alps to their southern declivity, you find the most formidable defensive positions at every turn of the road. Take the well-known Via Mala, for instance. There is not an officer but will tell you he might hold that defile with a battalion against an enemy, if he was sure of not being turned. But that is precisely the point. There is no mountain pass, even in the highest ridge of the Alps, but can he turned. Napoleon s maxim for mountain warfare was: Where a goat can pass, a man can pass; where a man, a battalion; where a battalion, an army. And Souwaroff had to do it, when he was closely shut up in the valley of the Reuss, and had to march his army along shepherds tracks, where but one man could pass at a time, while Lecourbe, the best French General for mountain warfare, was at his heels. It is this facility of turning an enemy which makes up and more for the strength of defensive positions, to attack which in front would often be perfect madness. To guard all roads by which a position can be turned would imply, in the defending party, such a dissemination of forces as must insure immediate defeat. They can, at best, be observed only, and the repulse of the turning movement must depend upon the judicious use of reserves and on the judgment and rapidity of the commanders of single detachments; and yet, if of three or four turning columns one only is successful, the defending party is placed in as bad a condition as if they had all succeeded. Thus, strategically speaking, the attack in mountain warfare is decidedly superior to the defense. It is the same when we come to look at the subject in a purely tactical light. The defensive positions will always be narrow mountain-gorges, occupied by strong columns in the valley and protected by skirmishers on the hights. These positions may be turned either from the front, by skirmishing parties climbing up the sides of the valley and outflanking the sharp-shooters of the defense, or by parties marching along the top of the ridge where this is practicable, or by a parallel valley the turning body profiting by a pass to fall on flank or rear of the defending post. In all these cases the turning parties have the advantage of command; they occupy the higher ground and overlook the valley occupied by their opponents. They may roll rocks and trees down upon them; for now-a-days no column is so foolish as to enter into a deep gorge before its sides are cleared; so that this late favorite mode of defense is now turned against the defenders. Another disadvantage of the defense is that the effect of firearms, on which it mainly rests, is very much reduced on mountainous ground. Artillery is either all but useless, or, where it is seriously used, is generally lost on a retreat. The so-called mountain artillery, consisting of light howitzers carried on the backs of mules, is of scarcely any effect, as the experience of the French in Algeria amply proves. As to musketry and rifles, the cover offering itself everywhere in such ground deprives the defense of a very great advantage that of having in front of the position open ground which the enemy must pass under fire. Tactically, then, as well as strategically, we arrive at the conclusion of the Archduke Charles of Austria, one of the best generals in mountain warfare and one of the most classical writers on that subject, that in this kind of war the attack is vastly superior to the defense. Is it then perfectly useless to defend a mountainous country? Certainly not. It only follows that the defense must not be a merely passive one, that it must seek its strength in mobility, and act, wherever opportunity offers, on the offensive. In alpine countries battles can hardly occur; the whole war is one continuous s eries of small actions, of attempts, by the attacking party, to drive the thin end of the wedge in one point or the other of the enemy s position, and then to press forward. Both armies are necessarily scattered; both must expose themselves at every step to an advantageous attack; both must trust to the chapter of accidents. Now, the only advantage the defending army can take is to seek out these feeble points of the enemy and to throw itself between his divided columns. In that case the strong defensive positions on which a merely passive defense would alone rely, become so many traps for the enemy where he may be allured into taking the bull by the horns, while the main efforts of the defense are directed against the turning columns, each of which may in its turn be turned and brought into the same helpless condition into which it intended to bring the defending party. It is, however, at once evident that such an active defense presupposes active, experienced and skillful generals, highly disciplined and mobile troops, and above all very skillful and reliable leaders of brigades, battalions, and even companies; for, on the prompt, judicious action of detachments, everything depends in this case. There is still another form of defensive mountain warfare which has become celebrated in modern times; it is that of national insurrection and the war of partisans, for which a mountainous country, at least in Europe, is absolutely required. We have four examples of it: the Tyrolese insurrection, the Spanish guerrilla war against Napoleon, the Carlist Basque insurrection, and the war of the Caucasian tribes against Russia. Though they have caused great trouble to the invaders, none of them, considered by itself, has proved successful. The Tyrolese insurrection was formidable only as long as it was supported, in 1809, by Austrian regular troops. The Spanish guerrillas, though they had the immense advantage of a very extensive country, owed the long continuance of their resistance chiefly to the Anglo-Portuguese army, against which the principal efforts of the French had always to be directed. The long duration of the Carlist war is explained by the degraded state to which the Spanish regular army had then been reduced, and by the constant negotiations between the Carlist and the Christina generals; and it cannot be taken as a fair specimen. Finally, in the Caucasian struggle, the most glorious of all to the mountaineers, their relative success has been due to the offensive tactics predominant in the defense of their ground. Wherever the Russians they and the British being of all troops the least fit for mountain warfare attacked the Caucasians, the latter have generally been defeated, their villages destroyed, and their mountain-passes secured by Russian fortified posts. But their strength lay in continued sallies from their hills into the plains, in surprises of Russian stations or outposts, in rapid excursions far to the rear of the Russian advanced line, in ambushes laid for Russian columns on the march. In other words, they were lighter and more movable than the Russians, and profited by this advantage. In fact, in every instance, then, of even temporarily successful insurrections of mountaineers, this success has been owing to offensive operations. In this they totally differ from the Swiss insurrections of 1798 and 1799, where we find the insurgents taking up some apparently strong defensive position and there awaiting the French, who in every instance cut them to pieces. The history of modern mountain warfare, of which we gave a short abstract in a previous article, most clearly proves that the mobility of the armies of our day is perfectly capable to overcome or to turn all the natural obstacle which an alpine country like Switzerland may oppose to their manoeuvres. Suppose, then, a war actually to break out between the king of Prussia and Switzerland, the Swiss must certainly look to other defences beside their much vaunted mountain-fortresses for the security of their country. In the case supposed above, the line on which Switzerland could be attacked, would extend from Constance along the Rhine to Basel: for we must consider both Austria and France as neutrals, as the active interference of either of them would secure such a crushing force to the attack that any strategical combinations against it would be useless. The northern frontier, therefore, is alone supposed to he open to invasion. It is protected in the first line by the Rhine, an obstacle of no great importance. This river runs along the attacked frontier for some 70 miles, and though deep and rapid, offers many favourable places for a passage. In the French revolutionary wars. Its possession has never been seriously contested, and indeed, a strong attacking army may always force the passage of any river on a portion of its course 70 miles long. False alarms, feigned attacks, followed up by sudden concentration of troops on the real points of passage are sure to succeed in each case. There are, besides, several stone bridges across it which the Swiss would scarcely attempt to destroy so seriously as to make them useless for the period of a campaign; and lastly, Constance being a German town situated on the southern bank of the Rhine, offers a convenient bridge-head for the Prussians to turn the whole of the line. But there is another obstacle at a short distance behind the Rhine, which heightens its indirect defensibility in a similar way as the Balkans, in Bulgaria, heighten the defensibility of the Danube. Three affluents of the Rhine, the Aare from the Southwest, the Reuss and Limmat from the Southeast, unite near Brugg, the two latter forming a right angle to the Aare, and then run due north towards the Rhine which they join at Coblenz (this Coblenz on the Aare and Rhine is of course not to be confounded with the fortress of that name on the Moselle and Rhine) about 10 miles from their unction. Thus the Aare from Brugg to the Rhine cuts in two the country covered by this latter stream, so that an invading army, having passed the Rhine, either above or below Coblenz, has before its front either the Limmat or the Aare, and is therefore stopped again by a defensible river. The salient angle, formed by the junction of the Aare and the Limmat (the Reuss forming but a strong second line to that of the Limmat) thus offers an important second position for defence. Its flanks are covered, to the left (west) by the lakes of Zurich, Wallenstadt, Zug and of the Four Cantons; neither of which a Prussian army, under the above-supposed circumstances, darest venture to turn. The position of the Aare and Limmat, with the Rhine in the rear of any army that came to attack it, therefore forms the principal strategical defence of Switzerland against an invasion from the North. Suppose the Swiss repulsed an attack on it, and followed up the victory by a countercharge and active pursuit, the beaten army would be lost, broken up, cut off, and ruined before it could retreat over the few bridges it might have on the Rhine. On the other hand, if the line of the lower Aare and Limmat were once forced, what would remain for the Swiss? Here again we must consult the configuration of the ground. Large armies cannot live in the high mountains, nor can they establish their chief bases of operations or magazines there. That some of the reasons why campaigns in alpine countries, if entered upon with considerable forces, have always been of very short duration. The Swiss could not, therefore, think of retreating in force into the high mountains; they must keep as long as possible to the more level territory where they find towns with all their resources and roads to facilitate transport. Now if a line is drawn from the point where the Rh ne enters the lake of Geneva at Villeneuve, to the point where the Rhine enters the Lake of Constance near Rheineck, this line will cut Switzerland in two portions the north-western of which (leaving the Jura out of consideration) will comprise the Swiss Lowlands, while the South Eastern comprises the Highlands or Alpine country. The strategy of the Swiss is thereby clearly defined. Their main body will have to retreat on the line Zurich Berne Lausanne Geneva, defending the open country inch by inch, and leaving the South-eastern mountains to the protection of such portions of the army as may have been cut off, and to the irregular warfare fire of the mountaineer Landsturm and free corps. The main body would be supported in this line of retreat by all the Southern affluents of the Aare, all of which run parallel to the Reuss and Limmat, and at Berne by the Aare itself which in its upper course also runs from the East to the North-west. The upper Aare once forced and Berne taken, there would remain but little chance to the Swiss to bring the war to a successful issue, unless the mountaineers and the new formed bodies from the South East succeeded in again occupying part of the plain and menacing the Prussian rear so seriously that a general retreat had to follow. But that chance may well be left out of consideration altogether. Thus the Swiss would have several good lines bf defence: first, the Aare and Limmat, then the Aare and Reuss, third the Aare and Emme (not to mention the intervening smaller affluents of the Aare) and fourthly the upper Aare, the left wing behind the morass extending from the lake of NeuchAtel to that river. The attack has its strategy equally as well prescribed by the configuration of the country as the defence. If the Prussians were to send their main body across the Rhine above Coblenz, and attack the position of the Limmat, they would take the bull by the horns; they would not only have to storm the position which Mass na in 1799 so successfully defended against the Austrians and Russians, but after taking it, find 5 miles further on the position of the Reuss, fully as strong; and then, from 2, 3, or 5 miles, another mountain-current would bar their path, until at last, after a succession of delays, combats, and losses, they would again find the Swiss posted behind the Emme, which river forms as serious an obstacle nearly as the Limmat. Unless political reasons. which we leave entirely beside, induced the Prussians to remain at a respectful distance from the French frontier, this way of attack would, therefore, he absolutely faulty. The real road into Switzerland crosses the Rhine between Basel and Coblenz; or, if part of the army should cross above Coblenz, a communication across the Aare between Brugg and Coblenz would have to be established at once so as to concentrate the main body on the left bank of the latter river. The direct attack on the line of the Aare turns the lines both of the Limmat and the Reuss, and may he made to turn the lines, too, of all the minor southern affluents of the Aare, almost as far as the Emme river. The line of the Limmat, too, is short, extending on its attackable front, from Zurich to Brugg, not more than 20 miles while the line of the Aare, from Brugg to Solothurn, offers to the attack an extent of 36 miles, and is not even absolutely secure from front attack above Solothurn. The left of the position, between Solothurn and Aarberg, is its weak point; once forced there, the line is not only lost to the Swiss, but they are cut off from Berne, Lausanne and Geneva, and have no retreat left but to the Southeastern highlands. The defence, however, is here supported by tactical obstacles. The more you ascend the Aare towards Solothurn, the more the higher ridges of the Jura approach the river, and obstruct military operations by their peculiar longitudinal valleys running all parallel to the Aare. The intervening ridges are far from being impassable, but yet the concentration of a large corps in such ground would presuppose very complicated manoeuvres always unpleasant in the face of the enemy and not easily undertaken by a general unless he has plenty of confidence in himself and his troops. The latter quality not being very common in the old Prussian generals who scarcely can be said to have seen active service since 1815, it is not likely that they would risk such a manoeuvre, but rather stick to half-measures on the flanks and concentrate their chief efforts on the lower. The Battle of Morgarten between Swiss volunteers and the troops of Leopold of Habsburg on November 15, 1315 ended in victory for the volunteers. At Murten (Canton of Freiburg) on June 22, 1476 and at Granson (Canton Vaud) on March 2, 1476, the Swiss defeated the troops of Charles the Bold, Duke of Burgundy.
Mountain Warfare in the Past and Present by Frederick Engels