On 25 June 1940, at 12:00 AM, the Maginot Line laid down its arms and surrendered. By the time the French armistice came into effect, 48 out of the 53 defensive positions in the mighty fortification complex spanning the French border with Germany were still undefeated. At the time, “this fortified system was the most complete and powerful ever conceived – let alone constructed.” Yet the reputation of the Maginot Line was largely ruined during the calamitous German invasion of May and June 1940, and many today would agree with General Patton’s observation that “Fixed fortifications are monuments to man’s stupidity.” The Maginot Line has come to be known as shorthand for an extensive defensive measure rendered useless by an Achilles heel, and it is accordingly perceived as a premier example of military inflexibility and conservatism. Yet it is worth reconsidering this surface evaluation and examining the Line’s original purpose and goals.
Built between 1928 and 1938, the Maginot Line was “an immense project comprising 100km of tunnels, 12 million cubic metres of earthwork, 1.5 million cubic metres of concrete, 150,000 tons of steel and 450km of roads and railways.” It was far more elaborate than just a simple concrete mound; it was designed with the latest technology and engineering know-how. Forts were vast underground complexes up to six stories deep, while the living conditions for the thousands of garrisoned troops were state of the art, with hospitals, living quarters, recreation areas, supply storehouses and even air conditioning. There were also subterranean rail lines and tunnels connecting various defensive positions together, and it is believed some areas were so well fortified that they could have withstood an atomic bomb. Aerial bombings and tank fire had little impact against the surface openings (called ouvrages), which were protected by steel-reinforced concrete up to 3.5 meters thick. Overall, there were 58 ouvrages on the section facing Germany, and 50 facing Italy. Between these main ouvrages there were various small defences, such as fortified machine-gun posts, minefields and anti-tank weapons. There were also “barbed-wire entanglements on reverse slopes and special anti-tank obstacles.”
The first concept of the fortifications that would become known as the Maginot Line arose from the French belief that the Treaty of Versailles failed to provide the state with sufficient security. The Line was the brainchild of its namesake, the Minister of War André Maginot. Maginot was not a military theorist, but was a wounded veteran of the Great War and, having been enormously influenced by the fortifications at Verdun, managed to persuade the government to invest in this defensive project in 1926.
Verdun had not only left its impact on Maginot’s thinking, it had schooled a generation of French military theorists in the value of strong fortifications, such as Fort Vaux and Fort Douaumont. Both were excellent examples of how well-maintained defences could tie up large numbers of enemy troops, buying time for allied troops to retreat, mobilise or counterattack. This was the fundamental philosophy and strategy of the Maginot Line. It was not a straight wall of forts, but a series of interlinked coordinated defensive points and “had never been conceived as a Great Wall of China sealing France off from the outside world.” Instead, if the Germans attacked across the Franco-German border, the Line was designed not to stop the invasion, but to slow it down by destroying as much of the invading force as possible. The time the line bought would be used by French forces to mobilise for a fierce counterattack to drive the invaders off French soil — something the importance of which had been stressed by the economic devastation of French territory in the First World War.
The Line was designed as an equaliser, a way for France to counter Germany’s demographic advantages. In the Interwar Period, France was faced with a terrifying population crisis, in part caused by the Great War, as during the last years of that struggle birth rates had halved. By 1939, France had a population of forty million compared to Germany’s seventy million, and the number of young men eligible for military service hit a nadir. Unlike Germany, France also had an empire which drained its manpower. Accordingly, we might see the Maginot Empire as an attempt to balance uneven scales.
For the diplomatic conditions of the 1920s tilted the scales only further against France. French leaders realised that victory in the Great War had only been won with the help of Russia, America and the British Empire. In the aftermath of that war, the Soviet Union was a pariah, the United States adopted an isolationist policy and Britain was extremely unwilling to make a “continual commitment”. Many also remembered that Britain had not initially joined France in the First World War. France was left without firm allies, facing an adversary with the ability to call up far more men than they ever could.
To deal with this unfavourable reality, two French military schools of thought emerged in the Interwar period. The first, championed by Colonel Charles de Gaulle, was a strategy based on fast and mobile warfare, which would have seen France produce superior armoured and airborne units. While General Heinz Guderain managed to persuade German leaders to adopt a similar doctrine (demonstrated in Blitzkrieg tactics), de Gaulle found that, because tanks and air forces were perceived as offensive weapons, and the population of France had no interest in starting another conflict, his project was politically impossible. Instead, France adopted Maginot’s philosophy of defensive fortifications.
Accordingly, the Maginot Line was extended to cover France’s eastern and northern borders, stretching from Luxembourg all the way across the border with Germany down to Switzerland. There was also a series of Alpine fortifications on France’s Italian frontier, which were called the Little Maginot Line. On the German border, the Maginot Line barred the two main invasion routes of the Rhine valley and the Moselle valley.
When it came to determine the locations of the fortresses, the question was raised of “why not be content to modernise and reinforce the old Belfort-Epinal-Toul-Verdun line of entrenched camps, which had proved its worth in the 1914-1918 War?” The primary reason was the significance, both psychological and economic, of Alsace-Lorraine, which was not defended by the lines of the First World War. This region contained much of France’s heavy industry, and a substantial portion of her natural resources; 42% of French iron ore, 36% of French pig iron, 33% of French steel and all of France’s potash came from this one region. At the same time, Alsace-Lorraine was a symbol of France’s struggle with Germany, having been seized by the Second Reich in 1871 but regained in 1918, and so leaving it undefended to a Teutonic onslaught was an understandably unenthusiastic prospect for French leaders.
The other geographical query was whether the Maginot Line should extent to the Channel, covering the border with Belgium. Hindsight has rendered this an obvious omission but at the time politics was once again a hindrance, as “even those who appreciated the weakness of the Belgian frontier could do little about it.” In the 1920s, France and Belgium were strong allies, and it was inconceivable for one to construct a series of gigantic fortifications along the shared boundary, as it would show one side was abandoning their ally abandoning to their fate.
Having anticipated this weakness, French military theorists hoped that the Maginot Line would also serve as a deterrent from attacking in that area, and would force the Wehrmacht to have to strike through the Low Countries. Under the Dyle Plan, French forces would move up into Belgium to shore up defences along the River Meuse and Albert Canal, which would allow for a continuous line of defences across the entire North-East. These positions would be linked to the Maginot Line through the Ardennes Forest, a region left largely undefended, as it was assumed the terrain was impassable. French experiences throughout the First World War had shown that armoured vehicles greatly struggled to move through rough terrain and with its rolling hills and dense forest, the Ardennes could certainly be considered rough terrain.
With hindsight, of course, it is apparent that ignoring the Ardennes was a fatal error. Yet the Maginot Line and the Dyke Plan had two major appeals to the French military. The first is that this plan would ensure fighting would occur off of French soil, and so there would be no repeat of the desolation of the Great War. The second is that it was assumed fighting in the Low Countries would draw Britain and other countries into the conflict, granting France the allies it needed to take on Germany.
Yet like many of the best laid plans, the Dyle Plan was a catastrophic failure. Britain and France declared war at the same time in response to the German invasion of Poland. The Wehrmacht stormed through the lightly defended Ardennes Forest, outflanked the Allied forces bottled in Belgium and conquered Paris and much of Northern France. German forces avoided most of the Maginot Line, only attacking a few of the fortifications on the edge.
The primary reason that the Maginot Line played so small a role in the Second World War was that, while military realities changed immensely between the 1920s and 1940s, French forces were unable to adapt and modify their overarching strategy. Experiences of tank warfare in the First World War had convinced French theorists that artillery and infantry would continue to dominate warfare, but by the Second World War, tanks and aircraft were the dominant means for victory. Even had France grasped the significance of these changes, economics would have made it difficult to adjust the nation’s comprehensive strategy. In the late 1920s, huge amounts of funding had been devoted to the Maginot Line before the Great Depression hit. This meant that there were limited funds available to start investing in upgrading an Air Force and mechanised divisions. Having already committed to building the Maginot Line, French leaders “neglected the remains of their forces in order to pay for it.”
Despite the technological changes which had occurred in the Interwar Period, the defences of the Line itself fared rather well. Various minor German attacks achieved limited successes and the Germans failed to capture a single major fortress before the armistice. On the Franco-Italian border, the Little Maginot Line was extremely effective, completely halting the Italian invasion until the armistice. The Line achieved its exact defensive purpose, and “demonstrated the effectiveness of the fortifications.”
Ultimately, any assessments of the Maginot Line’s relative futility is heavily dependent on its original goals. The Line itself was a technological and engineering masterpiece, and was almost impenetrable, with the Wehrmacht being unable to make any major breaches into the defences. Yet, however tactically brilliant the Line was, it was a strategic blunder. It put the Allies onto the defensive early on, actively hindered France in her attempts to modernise her army and inspired overconfidence. The Allies became predictable, slow and unwilling to assault Germany while the Wehrmacht was tied down in Poland. France fell in 1940 due to the perfect storm of German aggression and fortune combined with Allied lethargy and incompetence on an operational and strategic level. Furthermore, we should remember that the Line was sabotaged, almost from the start, by politics and technological developments. Ultimately, the fairest assessment of the Maginot Line was that it was a structural marvel, succeeding in aims of defence and deterrence, but that it was designed to wage a war that had already been fought. It had a crippling Achilles heel and lacked the calibre of generals needed to mask that fact.
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