Though many reasons have been given, it remains one of the most unexplained defeats in military history. No one in 1940 had predicted that France would fall in just six weeks to Nazi Germany. Adding to the phenomenon (to the chagrin of the MORS community) are legacy combat models and computer simulations that have similarly predicted a German defeat that ends with the French army in Berlin. [1]
Assuming then that the French and Allied armies were militarily defeated, that combat models (such as the ones featured) do not account for strategy, and that France’s fall and surrender were not at all caused by bad internal politics or domestic issues, how could we correctly go about proving it?
Perhaps the best way to prove a military defeat in this case is to simply look at a map.
Battle of France - 1940
Any accurate map for the Battle of France must show these two things:
1) a German breakthrough at the Ardennes, and
2) an initial Allied advance into the Low Countries that does not attempt to prevent or counter the German breakthrough. Because these key incidences will not change, no matter how many times we try to change the narrative for the fall of France, if would be difficult, even for the most stubborn historians, to not at least concede that French and Allied war planners had severely neglected to defend the Ardennes.
The strong case that military defeat came through the Ardennes —via surprise attack— thus opens up one of the most intriguing questions and unanswered problems from the Second World War. Given that France’s fall and quick defeat seems especially linked to a failure to defend the Ardennes, or —at a minimum— a failure to anticipate an attack from that direction, would accurate intelligence beforehand have made a difference? And if so, was there, somewhere behind the French and Allied lines, a terrific and historic failure to warn?
A Failure to Warn: The Case for Intelligence Failure
Because intelligence agencies exist primarily to prevent and thwart surprises, including surprise attacks, a failure to warn is generally ranked in intelligence studies as among the worst possible intelligence failures. Intelligence failures are commonly understood as
“failures to anticipate important information and events.” [2] This is especially true if warning from intelligence was possible and if errors in either intelligence reports or reporting can be demonstrated. The battle and fall of France shows that Germany achieved both operational and tactical surprise. The first with the surprising choice of assault through the Ardennes, and the second with the unexpected use of blitzkrieg and maneuver warfare. Thus, if warning from intelligence was possible —prior to or during the Battle of France—it has to be found in reporting on German army capabilities or in regards to their planning and operations.
At the planning and operations level, the most important warning that could have been achieved would undoubtedly have been the location of the German panzers. A failure to monitor the situation of the German panzer divisions prior to and during the Battle of France, in hindsight, could offer one of the more devastating critiques imaginable to French and Allied intelligence. Not only do the strength and locations of the German panzer divisions offer the strongest indicators for estimating Germany’s attack plans and maneuver possibilities, but the concentration of five armored divisions in Kleist’s Panzer Group offers the single best clue to identifying the main German attack.
Here, the case for French and Allied intelligence failure appears strong. At no time, for instance, did French and Allied intelligence ever produce accurate estimates or exact positions for all the German panzer divisions. [3] Precampaign estimates for the panzer divisions sometimes ran as high as 12 armored divisions with close to 7,000 tanks, which of course, was two more divisions and over twice as many German tanks in 1940 then there actually were. [4] In addition, when French reconnaissance planes and Allied agents began reporting a growing concentration of amour east of Luxembourg, these reports were either dismissed outright as “contradictory” or labeled a “secondary concentration” by French and Allied intelligence. Some planners and staff even went so far as to interpret the concentration of armor near Luxemburg and the Low Countries as a defensive measure for an alleged (and quite imaginary) Allied offensive; this, despite signals intelligence and enigma intercepts that suggested a possible German attack through the Ardennes. [5][6]
Once the invasion began on May 10
th, French and Allied intelligence again failed to raise alarm of German tank divisions advancing through the Ardennes. The most commonly accepted narrative is that the main German attack was not fully recognized or understood by the French High Command until the 14
th of May. [7] This is of course one day after the lead elements of Army Group A had begun pouring units across the Meuse. Though poor interpretation of aerial reconnaissance deserves much of the blame, as does abysmal reporting from the French cavalry who had spotted German tanks, the failure from French and Allied intelligence to identify and report the location of the main German attack was ultimately equaled and exasperated by another failure to warn others about German army capabilities. Few specialists had thought, for instance, that the Ardennes was a dangerous sector, even though wargames and map exercises had shown it was passable for German tanks. Few had thought aerial bombardment could be substituted for artillery, and few had thought speed, tempo, and the surprising range of armored columns matched with mechanized infantry and close air support could be used to penetrate or bypass linear fronts much more easily. This failure to know one’s enemy and recognize the technological return of maneuver to the battlefield thus left the French and Allied command without any coherent ideas or viable military options on how to deal with a German blitzkrieg. The end result of this unexpected development in military capability meant that the reveal of the main German attack —and its surprising method— could only be answered with additional surprise and shock. Not even Pearl Harbor or Barbarossa ever achieved this level of surprise and dislocation.
Other Factors
Though the combat and events in the Battle of France are undoubtably coupled with a high degree of surprise, where intelligence failure seems to be a reasonable explanation, there are many other important phenomenon and explanations that should be considered. Everything from poor army morale, training, to national decadence, to a lack of air and reserve forces, to the Maginot line and German risk-taking has been suggested. The most important counter arguments to the intelligence failure narrative include dysfunction, blundering, and rivalry in the French High Command, to the obvious neutrality and alliance failures between the Low Countries and the Allies. The first made French officials less likely to change strategy, adopt reform, or alter preconceptions, no matter what the intelligence reports actually said. The second proves the fall of France was an Allied failure, not just a French one. Had Belgium and the Netherlands been willing to allow early entry of the French army and had done more to defend their borders and the Ardennes at the onset, the outcome for the Battle of France might have been very different. The fact that these countries did not immediately renounce their neutrality after the Mechelen Incident, and the fact that the French High Command had doubled down on the Dyle Plan and the Breda variant, without thinking how it could be countered along a 600-mile front, shows how unique and devastating these two variables were.
In the end, the battle and fall of France offers one of the more intriguing cases of intelligence failures in military history. There is no doubt that accurate warning and intelligence, in whatever form, could have severely altered the Battle of France, which includes preventing the German breakthrough at the Ardennes. In addition, historians are reminded why good strategy is linked to good intelligence. It is not enough to examine the preconceptions and assumptions in French and Allied plans, and the decision making of the French general staff, without linking them back to their intelligence agencies and what they were being told. Yet, the true story in the Battle of France isn’t that intelligence had somehow failed to warn. No, its real story, found in one of the most shocking military defeats of all-time, is that warning and intelligence never played a role.
[1] Trevor N. Depuy, “Military History and Validation of Combat Models: A presentation at MORS Mini Symposium on Validation, 16 October 1990,” The International TNDM Newsletter. Vol 1, Number 4. February 1997.
[2] Thomas E. Copeland, “Intelligence Failure Theory,” Oxford Research Encyclopedias, Oxford University
Press, 2017. https://doi.org/10.1093/acrefore/9780190846626.013.27
[3] Stephen A. Shuker, “Seeking a Scapegoat: Intelligence and Grand Strategy in France, 1919-1940.”
Standard University Press, 2014. pp. 82.
[4] John Delaney, The Blitzkrieg Campaigns: Germany's 'Lightning War' Strategy in Action, (Arms & Armour,
1997), 77.
[5] Andre Ausems, “The Netherlands Military Intelligence Summaries 1 939-1 94 and the Defeat in the
Blitzkrieg o May 1940,” Military Affairs, Oct., 1986, Vol. 50, No. 4 (Oct., 1986), pp. 190-199.
https://www.jstor.org/stable/1988009...o_tab_contents
[6] Robert A. Doughty, The Breaking Point: Sedan and the Fall of France, 1940 (Mechanicsburg, PA,
Stackpole Books, 1990), 75.
[7] Doughty, 101.