World War II is replete with decisive moments, from Adolf Hitler’s decision to attack Poland in 1939 to President Harry S. Truman’s 1945 decision to drop the atomic bomb on Hiroshima. But General Heinz Guderian, Germany’s master tank commander, identified a decision made on May 24, 1940, as one that had the “most disastrous influence on the whole future course of the war.” It was Hitler’s notorious “halt order,” which stopped German armored units on the verge of seizing the port of Dunkirk before the defeated British Expeditionary Force (BEF) could evacuate from France.
The Battle of France began on May 10, 1940, when German forces invaded neutral Holland and Belgium, and British and French forces moved forward to meet them. A German armored spearhead soon blasted through the Ardennes Forest in Luxembourg and southern Belgium, shattered weak French defenses and outflanked the Anglo-French armies in Belgium. Ten days later, on the evening of May 20, German forces reached the English Channel, cutting off the BEF from the rest of France.
Britain’s Imperial General Staff at first underestimated the scope of the disaster and ordered General Lord Gort, commander of the BEF, to attack into the teeth of the German army. Rejecting these orders, Gort decided instead on May 23 to pull back and establish a defensive perimeter. Three days later the War Office in London ordered the BEF’s evacuation. By then the Germans had squeezed British and French forces into such a tight perimeter that their chances for evacuation depended entirely on holding the tiny French port of Dunkirk.
Just 12 miles away tanks of Guderian’s 1st Panzer Division had reached the Aa Canal, the last real obstacle before Dunkirk. Standing on a hill, Guderian could see the town walls. By the morning of the 25th his men had thrown pontoon bridges across the canal, allowing a few tanks to cross. Just as the advance was ready to resume, however, an order arrived from Army Group A, under General Gerd von Rundstedt: The tanks must halt at the Aa Canal. The destruction of British and French forces around Dunkirk would be left to the Luftwaffe. This order remained in effect for two days while Guderian’s tankers champed at the bit, watching in frustration as 340,000 British and French soldiers prepared to evacuate from Dunkirk right under their noses. The Luftwaffe proved unable to stop the famous Dunkirk armada of destroyers, fishing boats and everything in between from carrying the BEF back to England to fight another day.
The halt order left Guderian “speechless,” and it has sparked debate ever since. Some writers speculated—falsely—that Hitler had given the order out of a misguided sense of mercy, hoping the British were ready to make peace. German generals, in interviews and memoirs, chalked it up as yet another example of Hitler’s outrageous military stupidity, which had prevented them from winning the war.
In truth, there was plenty of blame to go around. On May 23 Field Marshal Hermann Göring had phoned Hitler and demanded his Luftwaffe be given primary responsibility for destroying the Allied forces around Dunkirk. Hitler was noncommittal, but the next day he visited Rundstedt at his headquarters at Charleville in the Ardennes. Some of Rundstedt’s generals had been whispering in his ear that German tank losses were dangerously high. Moreover, although an Allied armored counterattack at Arras on May 21 had failed, many German generals expected another, stronger counterattack. Worrying that a pellmell thrust toward Dunkirk might cost him more precious tanks and leave his southern flank vulnerable, Rundstedt had already issued a temporary halt order by the time Hitler arrived at his headquarters.
The führer vacillated between insecurity and overconfidence. The rapid advance of the panzers had surprised even him. Like many of his generals, he worried about tank losses and anticipated a long campaign to conquer Paris and the rest of France. The remaining tanks, he knew, must be conserved for future operations. He, too, worried about Allied counterattacks. Göring’s boasts about the Luftwaffe convinced Hitler the British couldn’t escape Dunkirk anyway.
After studying the map, Hitler confirmed Rundstedt’s halt order. He insisted the perimeter around Dunkirk be respected, to allow Göring’s planes plenty of room in which to operate. Guderian and other generals protested, but Hitler stood firm. The panzers held back.
Even at its most victorious, Hitler’s war machine was far from infallible. Uncertainty and indecision on the part of Rundstedt and some of his generals helped convince the führer to apply the brakes when victory lay within his grasp. It was one of the 20th century’s most fateful military decisions.
Originally published in the November 2011 issue of Military History. To subscribe, click here.