Sixty years after Operation Sea Lion became the greatest invasion that never was, the Allied forces take their victory for granted. It is hard to picture the Wehrmacht walking through the streets of London, or of Churchill escaping to his colonial lands to lead a British resistance. To truly understand the significance of the failure of Operation Sea Lion, one must understand the consequences of its success.

This exercise in speculative history must be based in some reality. By July of 1940, Operation Sea Lion was probably destined to fail. However, if not for a series of decisions by the German and British government before 1940, Sea Lion could have had a very different conclusion. Assume, for example, that a leader of the policy of appeasement, Lord Halifax , had taken control of England after the resignation of Chamberlain in 1940. Halifax could have calculated that an agreement with Hitler was preferable to resistance, and not launched a policy of preparedness with the tenacity of Churchill. Peaceful coexistence with the Nazis may have looked like a very positive outcome to many Brits in 1940, after seeing the effectiveness of their enemy on mainland Europe. Such a policy would have conceivably spared the British empire its war, while setting the Nazis free to attack into Bolshevik Russia. For the purposes of this speculation, however, we will imagine that an invasion of Britain was inevitable, and this is not a wild concoction, for Hitler seemed bent on domination of Western Europe. Also, it would be safe to assume, prior to 1940, that Hitler did not have great respect for the British military; it had trounced through Poland, the Low Countries, Scandinavia, and France despite the resistance offered by England. It is unlikely that Hitler would split world dominion with such a weak nation.

For Operation Sea Lion to have been successful, Hitler would have had to begun preparing for the invasion long before 1940. Directive 16 was issued on July 16, and the invasion date was set for September 15, a two month window. The Allies, on the other hand, had prepared for Operation Overlord for two years prior to the 1944 invasion of France. Extra time would have allowed for a buildup the German Navy, the subjugation of the British RAF, rehearsals of the invasion, and flexibility in weather conditions. Landing craft could be built, the geography of England studied, and several scenarios contemplated. It is a testament to Hitler's arrogance that he believed an invasion could be coordinated and executed in one summer, a possibility that was roundly dismissed by German naval leaders. Furthermore, a simultaneous attack on Britain and France in May of 1940 would have seen limited resistance on the shores of England, with the British Expeditionary Force engaged in a futile battle in France. A successful invasion would have trapped the BEF at Dunkirk, with the possibility of evacuation but no mainland to evacuate to.

These facts all prove that an invasion of England could have been achieved, if Hitler had issued instructions for a plan to draw up before he even invaded Czechslovakia or Poland. What would have been the consequences of this invasion? One possibilty is that Britain would act in a manner similar to its continental neighbors. British manufacturing plants could produce war goods to arm to Wehrmacht for Operation Barbarossa, possibly turning the tide of that battle. It is important to note that Hitler's army reached 200 miles of Moscow, and might have pushed through without the thorn of England in its side, and the benefit of English economic might. Thousands of British civilians would become subdued employees of the Third Reich. The 500,000 Jews of England would likely be treated in a manner similar to the Jews of other conquered nations of Europe, and been deported to concentration camps. (See map of camps) Another possibility is that Britain would take to heart Churchill's exhortation's to "fight on the streets", and the battle for mainland Britain would occupy the German army for years, extending World War II and bringing destruction upon the island. A widespread resistance in France was avoided because it would bring decimation upon that nation, but England looked prepared to risk that eventuality. Even with a fierce resistance, the German use of the British Navy would give them an advantage in Russia, and push the United States into further isolationism, with even President Roosevelt unable to imagine fighting the navies of all of Europe, and most of Asia, at the same time.

Without Britain on its side, the Allies would have faced certain defeat. Besides the probable success of Operation Barbarossa, without English bases there would be no Operation Overlord. The American attacks in North Africa, and through the "soft underbelly" of Europe would have been impossible, as it would involve attacking across the Atlantic Ocean. These failures lead to even more horrible speculation: Hitler could have achieved atomic power with British scientists, or worked to stage an invasion through the Middle East to unite with the Japanese empire and "squeeze" Russia to death. After conquering all of Europe and all of Asia, perhaps a manaical Hitler would have threatened US hegemony by attacking in South America, supported by Juan Peron and the fascists of Argentina!

Such possibilities may seem outlandish, but go to illustrate the effect that the failure of Sea Lion had on the war. As we continue to celebrate V-E day, it is important to remember that a few key mistakes are all that drew the line between defeat and victory in the summer of 1940.