Po and Rhone by Frederick Engels 1859


What is sauce for the goose is sauce for the gander. If we demand the Po and the Mincio for protection not so much against the Italians as against the French, we should not be surprised if the French likewise claim river lines for protection against us.

France’s centre of gravity does not lie on the Loire at Orléans but in the north, on the Seine, in Paris; and experience has twice proved that if Paris falls, all France falls.[199] Accordingly, the military significance of the configuration of France’s frontiers is determined primarily by the protection they afford Paris.

Straight lines from Paris to Lyons, Basle, Strasbourg and Lauterbourg are about the same length, some fifty-five miles; but any invasion of France from Italy aimed at Paris must advance between the Rhône and Loire in the Lyons area, or further north, if its communications are not to be endangered. Consequently, France’s Alpine frontier, south of Grenoble, is out of the question in connection with an advance on Paris; on this side Paris is fully covered.

At Lauterbourg the French frontier leaves the Rhine at a right angle and runs northwest; from Lauterbourg to Dunkirk it forms almost a straight line. The arc that we drew using Paris-Lyons as radius and passing through Basle and Strasbourg to Lauterbourg is broken at this point; the northern frontier of France is more like the chord to this arc, and the segment of the circle lying outside this chord does not belong to France. The shortest line from Paris to the northern border, Paris-Mons, is only half as long as the Paris-Lyons or Paris-Strasbourg radius.

These simple geometrical relationships explain why Belgium must be the battlefield of every war fought in the north between Germany and France. Belgium outflanks all Eastern France from Verdun and the Upper Marne to the Rhine. That is to say: An army invading from Belgium can reach Paris sooner than a French army stationed between Verdun or Chaumont and the Rhine; the army advancing from Belgium can therefore, if its offensive is successful, always drive a wedge between Paris and the French army of the Moselle or the Rhine; and all the more so since the way from the Belgian border to the points on the Marne that are decisive for the flanking action (Meaux, Chiteau-Thierry, Epernay) is even shorter than the road to Paris itself.

Not only that. Along the entire line from the Meuse to the sea the terrain does not offer an enemy the slightest obstacle on the way to Paris until he comes to the Aisne and the Lower Oise, the courses of which, however, are rather unfavourable to the defence of Paris against attack from the north. They did not present any serious difficulties to the offensive either in 1814 or 1815. But even conceding that they can be integrated into the defensive system of the Seine and its tributaries and were in part so integrated in 1814, that in itself is a confirmation of the fact that the real defence of Northern France. only begins at Compiègne and Soissons and that the first defensive position protecting Paris from the north is only twelve miles from Paris.

It is hard to imagine a weaker state frontier than the French frontier with Belgium. We know how Vauban laboured to make good the lack of natural means of defence by artificial ones; we also know how in 1814 and 1815 the attack went through the triple ring of fortresses almost without noticing it. We know how in 1815 fortress after fortress fell to the attacks of a single Prussian corps after incredibly brief siege and bombardment. Avesnes surrendered on June 22, 1815 after being shelled by ten field howitzers for half a day. Guise surrendered to ten field guns without firing a shot. Maubeuge capitulated on July 13 after 14 days of open approach trenches. Landrecies opened its gates on July 21 after 36 hours of open approach trenches and two hours of shelling, after only 126 bombs and 52 round shot had been fired by the besiegers. Mariembourg required, only pro forma, the honours of an open approach trench and a single twenty-fourpound ball and capitulated on July 28. Philippeville held out for two days of open approach trenches and a few hours of shelling, Rocroi 26 hours of open trenches and two hours of bombardment. Only Mézières held out for 18 days after the trenches were opened. There was a rage to capitulate among the commanders, not much weaker than in Prussia after the battle of Jena; and if it is argued that these places were out of repair in 1815, weakly garrisoned and badly equipped, it should not be forgotten that with some exceptions these fortresses must always be neglected. Vauban’s triple ring has no value today; it is a positive hindrance to France. None of the fortresses west of the Meuse protects any sector of the terrain by itself, and nowhere can four or five be found which form a group within which an army is protected and at the same time retains its ability to manoeuvre. The reason is that none of the fortresses is located on a large river. The Lys, the Scheldt and the Sambre only become important militarily on Belgian soil, and hence the action of these fortresses scattered in the open field does not extend beyond the range of their artillery. Except for a few large supply depots at the border which could serve as bases for an offensive into Belgium, and some points — If strategic importance on the Meuse and Moselle, all the other strong points and forts on France’s northern frontier have no effect beyond a quite useless scattering of forces. Any government that razed them would do France a service; but what would French traditional superstition say to that?

Thus, France’s northern frontier is highly unfavourable for defence; in fact it is indefensible, and Vauban’s ring of fortresses, instead of reinforcing it, is today only a confession of and monument to its weakness.

Like the Central European great-power theoreticians in Italy, the French too look beyond their northern frontier for a river line that could provide them with a good defensive position. What could it be?

The first line at hand would be that of the Lower Scheldt and the Dyle, continued to where the Sambre joins the Meuse. This line would give the better part of Belgium to France. It would comprise within itself almost all the famous Belgian battlefields on which Frenchmen and Germans have fought each other: Oudenarde, Jemappes, Fleurus, Ligny, Waterloo.[200] But it still ,would not make a line of defence; it would leave a great gap between the Scheldt and the Meuse, through which the enemy could pass without hindrance.

The second line would be the Meuse itself. If France held the left bank of the Meuse, its position would not be even as favourable as that of Germany in Italy if we had only the line of the Adige. The Adige line is fairly well rounded out, that of the Meuse very incompletely. If it flowed from Namur to Antwerp, it would make a much better frontier. Instead, it runs northeast from Namur and only after passing Venlo flows to the North Sea in a great arc.

In wartime the entire region north of Namur between the Meuse and the sea would only be covered by its fortresses; for an enemy crossing of the Meuse would always find the French army in the South Brabant plain, and a French offensive on the German left bank of the Rhine would immediately come up against the strong Rhine line, and quite directly against the entrenched camp of Cologne. The receding angle of the Meuse between Sedan and Liège contributes to making the line weaker, even though the angle is filled by the Ardennes. Thus, the line of the Meuse gives the French too much for good defence of the frontier at one point, and too little at the others. Let us continue.

If we put one point of our compasses on Paris on the map and, with Paris-Lyons as our radius, describe an arc from Basle to the North Sea, we find that the course of the Rhine from Basle to its mouth follows this arc remarkably accurately. Within a few miles, all the important points on the Rhine are equally distant from Paris. This is the actual, real reason for the French desire for the Rhine boundary.

If France has the Rhine, then Paris will, with respect to Germany, really be the centre of France. All the radii from Paris to the attackable frontiers, whether on the Rhine or in the Jura, have the same length. At every point the enemy is faced by the convex periphery of the circle and must manoeuvre on detours behind it, while the French armies move on the shorter chord and can forestall the enemy. The equal lengths of the operational and withdrawal lines of the several armies make concentric withdrawal much easier, rendering it possible to combine two of these armies at a given point for a massive blow at the still divided enemy.

Possession of the Rhine frontier would make France’s defensive system, so far as the natural preconditions are concerned, one of those that General Willisen calls “ideal”, one that leaves nothing to be desired. The strong inner defensive system of the Seine basin, which is formed by the Yonne, Aube, Marne, Aisne and Oise rivers flowing like a fan into the Seine, and on which Napoleon gave the Allies such harsh lessons in strategy in 1814,[201] is thus first given uniform protection in every direction; the enemy will reach it at much the same time from any side and can be held at the rivers until the French armies are in a position to attack each isolated enemy column with united forces; whereas without the Rhine line, the defence can only make a stand at the most decisive point, at Compiègne and Soissons, only twelve miles from Paris. There is no other region in Europe in which defence would be supported by railways in rapidly concentrating large forces so much as in the country between the Seine and the Rhine. Railways radiate from Paris as a centre to Boulogne, Bruges, Ghent, Antwerp, Maastricht, Liège and Cologne, to Mannheim and Mainz via Metz, to Strasbourg, to Basle, to Dijon and Lyons. At whatever point the enemy can be present in greatest strength, the entire strength of the reserve army can be thrown against him by railway from Paris. In particular, the inner defence of the Seine basin is reinforced even more by the fact that all the railway radii within it run through the river valleys (the Oise, the Marne, the Seine, the Aube, in part the Yonne). But that is not all. Three concentric arcs of railways run at roughly equal distances from Paris for a quadrant or more in length: the first is the set of lines on the left bank of the Rhine, which now run almost without a break from Neuss to Basle; the second goes from Ostend and Antwerp through Namur, Arion, Thionville, Metz and Nancy to Epinal, and is also as good as complete; lastly the third extends from Calais via Lille, Douai, St. Quentin, Rheims, Châlons-sur-Marne and St. Dizier to Chaumont. Here everywhere the means are available to concentrate masses of troops at any given point in the shortest time, and nature and skill, without any fortifications, would make the defence so strong by reason of manoeuvrability that an invasion of France would come up against a much different resistance than in 1814 and 1815.

The Rhine would have only one defect as a frontier river. As long as one bank is all German and the other all French, the river is not dominated by either of the two countries. A stronger army, of whichever nation, could nowhere be denied crossing; we have seen that a hundred times, and strategy explains why it must be so. In the face of a German offensive with superior forces the French defence could only call a halt further back: the army of the north on the Meuse between Venlo and Namur; the army of the Moselle on the Moselle, perhaps at the confluence with the Saar; the army of the Upper Rhine on the Upper Moselle and the Upper Meuse. In order to dominate the Rhine fully and be able to oppose an enemy crossing energetically, the French would therefore have to have bridgeheads on the right bank. It was therefore very logical on Napoleon’s part that he summarily incorporated Wesel, Kastel and Kehl into the French Empire. As things stand today, his nephew would ask, as a complement to the fine fortresses the Germans have built for him on the left bank of the Rhine, for Ehrenbreitstein, Deutz and if need be the Germersheim bridgehead as well. In that case France’s military-geographical system would be complete for the offensive or the defensive, and any new annexation would only damage it. And how natural the system seems, how readily understandable, was strikingly shown by the Allies in 1813. France had set up the system only 17 years earlier, and yet it was so much. taken for granted that the high Allies, despite their preponderance of strength and the defencelessness of France, shuddered at the thought of touching it, as if it were a sacrilege; and if they had not been carried along by the German nationalist elements of the movement, the Rhine would still be a French river today.

But if we should cede to the French not only the Rhine but also the bridgeheads on the right bank, the French would have fulfilled the duty to themselves that we are fulfilling to ourselves, as Radowitz, Willisen and Hailbronner see it, by holding the Adige and the Mincio with the Peschicra and Mantua bridgeheads. But therewith we would have made Germany as totally helpless vis-à-vis France as Italy is now vis-à-vis Germany. And then Russia, as in 1813, would he the natural “liberator” of Germany (as France or rather the French Government presents itself as the “liberator” of Italy now) and would only ask, in payment for its unselfish exertions, some small districts to round out Poland-say Galicia and Prussia; for Poland too is “outflanked” by them!

What the Adige and the Mincio are for us, the Rhine is for France, and much more vital. If Venetia in the hands of Italy, and possibly of France, flanks Bavaria and the Upper Rhine and uncovers the road to Vienna, so Belgium and Germany, via Belgium, flank all of Eastern France and uncover the road to Paris much more effectively. From the Isonzo to Vienna there are still sixty miles to go, in a terrain where the defence can still make a stand somehow; from the Sambre to Paris is thirty miles, and it is only twelve miles from Paris, at Soissons or Compiègne, that the defence has any sort of a protective river line. If, as Radowitz says, giving up the Mincio and the Adige would put Germany from the outset in a position it would otherwise reach after losing an entire campaign, France — with its present frontiers is situated as though it had possessed the Rhine line and lost two campaigns, one around the Rhine and Meuse fortifications and the other in the field, on the Belgian plain. Even the strong position of the fortresses of Upper Italy is in a way repeated on the Lower Rhine and the Meuse; would it not be possible to make Maastricht, Cologne, Jillich, Wesel and Venlo, with a little assistance and a couple of intermediate points, into an equally strong system completely covering Belgium and North Brabant that would enable a French army not strong enough for the open field to manoeuvre so as to hold a much stronger enemy army at the rivers and finally to use the railways to withdraw to the Belgian plain or to Douai without hindrance?

Throughout this study we have assumed that Belgium was completely open to the Germans for. attacking France and was an ally of Germany. Since we had to argue from the French standpoint, we had the same right to that assumption as our opponents on the Mincio, when they assumed that Italy, even a free and united Italy, would always he hostile to the Germans. In all such matters it is quite correct to look into the worst case first and get prepared for it as a start; and that is how the French must go about it when considering the defensibility and strategic configuration of their northern frontier today. That Belgium is a neutral country according to European treaties, just like Switzerland, is something we may ignore here. In the first place, it remains to be proved by the actual course of history that in a European war this neutrality amounts to anything more than a sheet of paper, and secondly, France cannot by any means count on it so firmly that it could, militarily, treat the entire frontier with Belgium as if the country formed a protective arm of the sea between France and Germany. Ultimately, the weakness of the frontier remains the same whether it is really actively defended or Whether troops are only dispatched there to occupy it against possible attacks.

We have drawn the parallel between the Po and the Rhine pretty closely. Apart from the larger dimensions at the Rhine, which however would only strengthen the French claim, the analogy is as complete as one could desire. It is to be hoped that in the event of war the German soldiers will defend the Rhine on the Po practically with greater success than the Central European great-power politicians do theoretically. They defend the Rhine on the Po, to be sure, but — only for the French.

As for the rest, in case the Germans should at some time be so unfortunate as to lose their “natural frontier”, the Po and the Mincio, we shall carry the analogy still further. The French possessed their “natural frontier” only seventeen years and by now have had to get along without it for almost forty-five years. During this time their best military men have come to realise, theoretically too, that the uselessness of the Vauban ring of fortresses against invasion is based on the laws of modern warfare, and hence that it was neither accident nor the trahison [treason] they like to invoke that allowed the Allies in 1814 and 1815 to march through between the fortresses undisturbed. Hereafter it was even clearer that something had to be done to protect the exposed northern frontier. Obviously, though, there was no prospect of obtaining the Rhine frontier in the near future. What was to be done?

The French managed in a way that honours a great people: They fortified Paris; for the first time in modern history, they performed the experiment of converting their capital into an entrenched camp on a colossal scale. The military experts of the old school shook their heads over this unwise undertaking. Money thrown away for nothing but French swagger! Nothing behind it, pure humbug; who ever heard of a fortress nine miles in circumference and with a million inhabitants! How is it to be defended, unless half the army is thrown into it as garrison? How are all those people to get their provisions? Madness, French vanity, godless frivolity, a repetition of the Tower of Babel! That is how the military pedants judged the new undertaking, the same pedants who study siege warfare from a Vauban hexagon and whose passive method of defence knows no greater offensive counterblow than the sortie of a column of infantry from the covered way to the foot of the glacis! But the French kept on calmly building and have had the satisfaction that, even though Paris has not yet undergone the test of fire, the unpedantic military men of all Europe agree with them, that Wellington drew up plans for the fortification of London, that, if we are not mistaken, construction of detached forts around Vienna has already begun and the fortification of Berlin is at least under discussion. They themselves must have learned from the example of Sevastopol how tremendously strong a colossal’ entrenched camp is if it is occupied by an entire army and the defence is conducted offensively on a large scale. And Sevastopol had only a rampart, no detached forts, only field works, no walled escarpments!

Ever since Paris has been fortified, France can do without the Rhine frontier. Like Germany in Italy, it will have to conduct its defence on the northern border offensively at first. The arrangement of the railway network shows that this has been understood. If this offensive is repulsed, the army makes its stand, a definitive one, on the Oise and the Aisne; for furtlier advance 1)y the enemy would no longer serve any purpose, since the army of invasion from Belgium would be too weak by itself to act against Paris. Behind the Aisne, in solid communication with Paris, at worst behind the Marne, with its left wing supported on Paris, in an offensive flanking position, the French northern army could await the arrival of the other armies. The enemy would have no alternative but to move on Château-Thierry and operate against the communications of the French Moselle and Rhine armies. But the action would be far from having the decisive importance it would have had before the Paris was fortified. At the worst, the withdrawal of the other French armies behind the Loire cannot be cut off; concentrated there, they will still be strong enough to be dangerous to an invasion army weakened and split by the investment of Paris, or to break through to Paris. In a word: The fortification of Paris has blunted the point of a flanking movement through Belgium; it is no longer decisive; and it is easy to calculate the disadvantages it entails and the means to be employed against it.

We should do well to follow the example of the French. Instead of letting ourselves be deafened by the outcry about the indispensability of a possession outside Germany, which becomes more and more untenable for Germany every day, we should do better to prepare ourselves for the inevitable moment when we give up Italy. The earlier we set up the fortifications that will then be needed, the better. To say more about where and how they are to be set up than the ideas previously suggested, is not our function. Only let us not put up illusory strong points and, relying on them, neglect the only fortifications that can enable a retreating army to make a stand: entrenched camps and groups of fortresses on rivers.

Footnotes from MECW

199 Paris was twice captured by the forces of the anti-Napoleonic coalition. on March 30-31, 1814 and July 6-8, 1815.

200 The battle of Oudenarde took place on July 11, 1708, during the War of the Spanish Succession. The French were defeated by the allied Arigio-Austrian forces.

At the battle of Jemappes on November 6, 1792 the French revolutionary, army won a big victory over the Austrians.

At the battle of Fleurus on June 26, 1794 the French defeated the Austrians. This victory made it possible for the French to enter Belgium and occupy it.

At the battle of Ligny on June 16, 1815 the Prussians were routed by the French. This was the last battle won by Napoleon I.

At the battle of Waterloo on June 18, 1815 Napoleon’s army was defeated by the allied forces of Britain, Holland and Prussia.

201 At the battles of Montmirail, Château-Thierry, Reims and others, in February and March 1814 Napoleon defeated superior forces of the sixth anti-French coalition.