Editing Maginot Line (section)

==== German economic superiority ====
After 1918, the German economy was twice as large as that of France; Germany had a population of 70 million compared to France's 40 million, and the [[Economy of France|French economy]] was hobbled by the need to reconstruct the enormous damage of World War I, while German territory had seen little fighting. French military chiefs were dubious about their ability to win another war against Germany on its own, especially an offensive war.{{sfn|Keylor|2001|p=122}} French decision-makers knew that the victory of 1918 had been achieved because the British Empire and the United States were allies in the war and that the French would have been defeated on their own.{{sfn|Keylor|2001|pp=121–122}} With the United States isolationist and Britain stoutly refusing to make the "continental commitment" to defend France on the same scale as in World War I, the prospects of Anglo-American assistance in another war with Germany appeared to be doubtful at best.{{sfn|Keylor|2001|pp=121–122}} Versailles did not call for military sanctions in the event of the German military reoccupying the Rhineland or breaking Part V, while Locarno committed Britain and Italy to come to French aid in the event of a "flagrant violation" of the Rhineland's demilitarised status, it did not define what a "flagrant violation" would be.{{sfn|Keylor|2001|p=122}} The British and Italian governments refused in subsequent diplomatic talks to define "flagrant violation", which led the French to place little hope in Anglo-Italian help if German military forces should reoccupy the Rhineland.{{sfn|Keylor|2001|p=122}} Given the diplomatic situation in the late 1920s, the [[Quai d'Orsay]] informed the government that French military planning should be based on a worst-case scenario that France would fight the next war against Germany without the help of Britain or the United States.{{sfn|Keylor|2001|p=122}}

France had an alliance with [[Belgium]] and with the states of the ''[[Cordon sanitaire (international relations)|Cordon sanitaire]]'', as the French alliance system in [[Eastern Europe]] was known. Although the alliances with Belgium, [[Second Polish Republic|Poland]], [[First Czechoslovak Republic|Czechoslovakia]], [[Kingdom of Romania|Romania]] and [[Kingdom of Yugoslavia|Yugoslavia]] were appreciated in Paris, it was widely understood that this was no compensation for the absence of Britain and the United States. The French military was especially insistent that the population disparity made an offensive war of manoeuvre and swift advances suicidal, as there would always be far more German divisions; a defensive strategy was needed to counter Germany.{{sfn|Keylor|2001|p=122}} The French assumption was always that Germany would not go to war without conscription, which would allow the German Army to take advantage of the ''Reich''{{'}}s numerical superiority. Without the natural defensive barrier provided by the [[Rhine]] River, French generals argued that France needed a new defensive barrier made of concrete and steel to replace it.{{sfn|Keylor|2001|p=122}} The power of properly dug-in defensive trenches had been amply demonstrated during World War I, when a few soldiers manning a single machine gun post could kill hundreds of the enemy in the open and therefore building a massive defensive line with subterranean concrete shelters was the most rational use of French manpower.{{sfn|Keylor|2001|p=123}}

The American historian William Keylor wrote that given the diplomatic conditions of 1929 and likely trends – with the United States [[United States non-interventionism|isolationist]] and Britain unwilling to make the "continental commitment" – the decision to build the Maginot Line was not irrational and stupid, as building the Maginot Line was a sensible response to the problems that would be created by the coming French withdrawal from the Rhineland in 1930.{{sfn|Keylor|2001|p=123}} Part of the rationale for the Maginot Line stemmed from the severe French losses during the First World War and their effect on the French population.{{sfn|Young|2005|p=13}} The drop in the birth rate during and after the war, resulting in a national shortage of young men, created an "echo" effect on the generation that provided the French conscript army in the mid-1930s.{{sfn|Young|2005|p=13}} Faced with a manpower shortage, French planners had to rely more on older and less fit [[reservist]]s, who would take longer to mobilise and would diminish the French industry because they would leave their jobs. Static defensive positions were therefore intended not only to buy time but to economise on men by defending an area with fewer and less mobile forces. However, in 1940, France deployed about twice as many men, 36 divisions (roughly one third of its force), for the defence of the Maginot Line in Alsace and Lorraine. In contrast, the opposing German [[Army Group C]] only contained 19 divisions, fewer than a seventh of the force committed in the [[Manstein Plan]] for the invasion of France.{{sfn|Frieser |2005|p=88}} Reflecting memories of World War I, the French General Staff had developed the concept of ''la puissance du feu'' ("the power of fire"), the power of [[artillery]] dug in and sheltered by concrete and steel, to inflict devastating losses on an attacking force.{{sfn|Young|2005|p=36}}