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Did the US Consider NOT Using the Atomic Bombs? & The Operation Sea Lion Fantasy | WW2 Brain Bucket
WW2 historian Paul K. DiCostanzo explores if the US ever considered not using the Atomic bomb, and why Operation Sea Lion never occurred.
In this installment of the WW2 Brain Bucket, WW2 historian Paul K. DiCostanzo examines your questions about if the US ever considered not using the atomic bombs, and the feasibility of Operation Sea Lion – Nazi Germany’s plan for invading Britain in autumn 1940.
Now, on to your questions!
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“Did the Allies ever consider not dropping the Atomic bombs on Japan? Would they ever not have chosen to do so?” – Wyatt, Texas
To frame the answer to your question, it is important to make clear this is not an evaluation of what primarily triggered Japanese surrender. Was it the atomic bombs? Was it the Soviet invasion of Manchuria? Those issues are not on the table. Nor is it a discussion regarding the morality of having used the atomic bombs. Instead, it is a look at Allied decision making relative to how and why they chose to use the atomic bombs, based on the information available at the time, the strategic situation, and it’s critical political considerations.
So, would the US have ever chosen to withhold the atomic bombs use against Japan? In the eyes of top American war planners, any scenario short of the Japanese unexpectedly accepting the Potsdam Declaration – the reaffirmation by the Allies in their calling for unconditional Axis surrender – occurring prior to the availability of the atomic bombs, the answer is an unequivocal “no.” When analyzing both the political and military ramifications of the first US atomic bombs becoming available for use in July 1945, there is exactly zero chance the Allies would have passed on using them against Japan if they were still at war.
There are myriad reasons why the United States chose to use the atomic bombs. To understand the Allied war planner’s and President Truman’s decision, one must consider the combination of the resources invested in the bomb’s development, the aspiration for it’s potential as a strategically significant weapon, the political fallout of not using them prior to a conventional invasion of Kyushu and Honshu, and the lack of viable conventional alternatives to force Japanese capitulation. These aforementioned factors made the use of the atomic bombs the most preferable option available to Allied war planners at the time.
Before fully diving into this rabbit hole, let’s discuss why the Western Allies constructed the atomic bombs in the first place.
Why The Allies Originally Developed the Atomic Bomb
As many know, the atomic bombs were developed in a top secret joint US/British/Canadian venture, the Manhattan Project, to outpace Nazi Germany’s goal for creating the atomic bomb themselves. What the western Allies couldn’t have known at the time – yet is now clear to historians – is that Nazi Germany was nowhere close to successfully building their own bomb.
Germany by 1942 had focused their efforts primarily into other so-called “Wunderwaffe,” or Vengeance Weapons. Wunderwaffe projects notably included the development of the infamous V-1 “Flying Bomb,” it’s successor the V-2 rocket, as well as the jet engine aircraft Me 262 to name a few.
Third Reich research towards developing an atomic bomb experienced numerous complications; including decentralized research efforts, a combination of myriad government inter-departmental and project in-fighting, all of which are common fare in many other endeavors during the Third Reich at war. Germany’s war effort in every facet was experiencing an ongoing competition for scarce material resources, Wunderwaffe projects included.
These matters were further confounded by many major figures in the Reich scheming to have these projects fall within their personal fiefdoms, aiming to receive sole credit for their success. The strictly scientific minds involved in Nazi Germany’s research and development were also revealing in this respect.
Werner Heisenberg was Nazi Germany’s foremost theoretical physicist, a pioneer in quantum mechanics, the creator of the famed Heisenberg Uncertainty Principle, and recipient of the 1932 Nobel Prize in Physics. Heisenberg was also one of the major professional scientific point-men in Nazi Germany’s construction of an atomic bomb, and privy to many of the details relating to Nazi Germany’s progress toward building their first atomic atomic bomb. Heisenberg upon first learning of the atomic bombs use against Japan was in abject disbelief.
Heisenberg could not imagine how the Western Allies constructed it, based on the countless research hurdles faced in his quest to do so. He initially thought the news was either Allied propaganda, or perhaps a uniquely destructive – but conventional – bomb. Heisenberg was quickly disabused.
Heisenberg’s reaction is remarkably telling, as he was among the few in Germany who had the relevant insights to arrive at such an original conclusion. Heisenberg was not alone, as there were higher ranking members of Germany’s government who had expressed similar sentiments about the prospects for its construction years earlier.
Hitler himself thought weaponization of the atomic bomb wasn’t feasible in time for use in the war. Hitler in holding that belief directed resources be allocated toward more potentially useful Wunderwaffe projects. Such are the ropes in a despotic totalitarian state, where the whims of the all-powerful leader dictate said priorities. Unknowingly to the Allies, it gave them a tremendous advantage in the high stakes of creating the first atomic weapon.
The Allies original intent was to use their atomic bombs on Germany, however Nazi Germany’s unconditional surrender in May 1945 occurred two months prior to the first successful test detonation in New Mexico.
When getting to the heart of the Allies unswerving decision to eventually use the atomic bombs, theirs was more than a mere wartime opportunity that dictated its eventual use. The financial dynamics of the Manhattan Project played a definitive role in its own right.
Follow the Money: The Cost of Developing the Atomic Bombs
The Manhattan Project was a remarkably high expenditure, costing the US $2B ($28B as of 2020) to complete. The project was the second largest US wartime expenditure after the $3B price tag for the B-29 contract. The Manhattan Project’s cost alone made the atomic bombs usage a near fait-accompli, if the Allies still found themselves at war when they became available.
When considering the governmental realities of undertaking a program as ambitious and expensive as the Manhattan Project, it accompanies a great political pressure to see the final product prove useful towards Allied victory.
Forgoing their use would have lead to later accusations of profligate spending, questions about why that same financial appropriation was not used towards other efforts that could have proven useful in the war, as well as outright questioning the Truman administration’s judgement. Financial appropriations aside, the atomic bombs had additional political sensitivities as well.
The Political Implications of Not Using the Atomic Bombs – Needlessly Squandering Allied Lives
Powers engaged in total war against an implacable foe do not withhold usage of a weapon that might be a quantum leap in weapons technology. Especially a weapon that might also have revolutionary strategic implications.
Nor would any wartime leader want to face the uproar of their nation – especially in a Western democracy – answering for why their sons and daughters died during a conventional invasion of Japan, that might have been made otherwise unnecessary with use of the atomic bombs. On a political basis, such a situation is odious at best.
President Truman gave the final green light to bomb Hiroshima and Nagasaki, and nor would FDR have hesitated to do the same.
When one takes a prospective view of the war during the summer of 1945, it’s clear Allied war planners had much to consider. Especially the numerous particulars of deploying the atomic bombs.
The Secret Debate of How, When & Where to Use the Atomic Bombs
The US “Interim Committee” founded in May 1945, was a small consultative body focusing on early US nuclear doctrine and use of atomic energy; prior to establishing the policy of full civilian control of nuclear weapons and energy that exists to this day.
Interim Committee members included a select few with the national security clearance allowing them full knowledge of the highly secretive and sensitive Manhattan Project; such as President Truman, Secretary of State James Byrnes, and Secretary of War Henry Stimpson to name but a few.
The committee’s foremost priority was advising President Truman on how the atomic bombs might best be used against Japan.
The internal deliberations of the Interim Committee – in so far as is known – never seriously floated the prospect of withholding use of their new weapon.
Before discussing further how the atomic bombs might have been used, Allied war planners foremost needed to address another burning question: Was there any additional feasible conventional strategic alternatives to defeat Japan beyond using the atomic bombs, or an outright invasion of the Japanese home islands?
The Blockade Option: A Lesser-Known and Problematic Alternative to Invasion and Dropping the Atomic Bombs
During the Second World War in the Pacific, the US conducted a highly effective naval blockade of the Japanese home islands – one now all but forgotten in popular historical memory. The Battle of the Atlantic and the German U-Boat campaign interdicting Allied merchant shipping dominates most historic attention. However, the most effective maritime interdiction campaign of the war was enacted by US Navy submariners against the Empire of Japan.
Aside from a conventional invasion of Honshu and Kyushu, marine interdiction of Japan was the only other realistic conventional alternative the Allied powers had for potentially coercing Japanese capitulation, thus ending the war. Yet that approach possessed clear and considerable drawbacks.
The nature of economic strangulation by naval blockade in the Pacific was a so-called, “Known-Unknown,” requiring an unknown period of time to potentially succeed. For all the wartime resources at the command of Allied forces in the Pacific during the summer of 1945, time was never among them.
Warfare dictates maintaining the initiative over the enemy, thus never providing one’s enemy the benefit of additional time. Hence the cost in possible time to undertake a successful blockade may have proven very high indeed, if it worked at all.
As is invariably the case in war, decisive action was required to achieve Japanese surrender. The Allies by waiting for a blockade to succeed would provide Japan further time to enact greater defensive measures for resisting a conventional Allied invasion of Honshu and Kyushu – if it became necessary. In doing so, the already tremendous cost of a conventional invasion would have certainly increased as well.
Moreover the so-called “Known-Known,” was that the Japanese conception of resistance did not recognize privation in the least. There was a genuine Allied fear that all Japanese people would continue to resist to the point of their own collective obliteration, and were unlikely to value the dwindling means of their basic sustenance in the process. Indeed by late in the war, Japan was taking active steps to psychologically and physically train their civilian populous to do just that.
With the highly problematic conventional alternatives understood, how else might the Allies have used the atomic bombs other than how they eventually did?
Options for How the US Could Have Used their Atomic Bombs Differently
During the top level discussions on how to use the atomic bombs, the merits of a “technical demonstration” for Japanese benefit were debated. The “technical demonstration” would be an unambiguous detonation at a safe but visible distance; making clear the novel devastating weapon the Allies possessed, ultimately serving to encourage immediate surrender.
The “technical demonstration” concept was dismissed, primarily due to the committee’s belief that only the use of the bomb on a viable Japanese target would properly convey the reality of their new weapon’s lethality as intended.
The “Target Committee” – the immediate predecessor to the Interim Committee – was headed by General Leslie Groves in early 1945. General Groves was also the primary professional military head of the Manhattan Project.
As the Target Committee’s name indicates, these discussions were considering the best possible locations, as well as best possible uses, for dropping the atomic bombs.
According to the Target Committee, they generated a number of options for the bombs use:
• Use as a tactical weapon, assisting the conventional invasion of the Japanese home islands.
• Use as a demonstration before primarily Japanese civilian observers, the aforementioned “technical demonstration.”
• Use as a demonstration before a Japan military target, with primarily military observers.
• Use against a primarily military target.
• Use against a city with a military target, providing advance warning.
• Use against a city with a military target, forgoing advance warning.
As indicated above, it’s clear what the final choice was for Allied war planners. The next challenge was deciding where to use the bombs.
List of Target Locations
Aside from the eventual targets of Hiroshima and Nagasaki, the original draft of target candidates cities included Kyoto as the foremost preferred target. Kyoto was rejected for a number of reasons. Some of those reasons included its status as Japan’s long famous historic cultural epicenter, containing Emperor Hirohito’s personal residence.
Kyoto was removed from the list, partially in thanks to Henry Stimpson. It is said that Stimpson held a personal fondness for Kyoto, after honeymooning there with his wife many decades prior. Stimpson sought to protect this cultural treasure, fully understanding that it would create outright resentment by the Japanese for generations if it were obliterated.
Kyoto’s bombing would also have likely killed Emperor Hirohito. Hirohito as Emperor was thought by his subjects to be a living deity – the direct ancestor of the Shinto Sun Goddess Amaterasu. The Allies by using the atomic bomb on Kyoto might have unnecessarily created a divine martyr of Hirohito, reinforcing the already implacable resistance of the Japanese people.
Hirohito was also the lone figure who through his divine status could unilaterally command Japan’s surrender. In total, all of these outcomes were well worth avoiding at all costs by nixing Kyoto from the list.
Tokyo for all its importance was not considered, as shortly before it was almost completely destroyed following the campaign of Allied incendiary bombings. Indeed, choosing mainland targets was very difficult, as so many Japanese cities had been leveled by Allied conventional bombing.
When it comes to the decision to use the atomic bombs against Japan, it’s important to also consider how Allied war planners viewed their Japanese enemy in July 1945. In addition to how that impression informed their decision making.
How the Allies Viewed Japanese Resistance in Summer 1945
In late July 1945, the US had just achieved victory on Iwo Jima and Okinawa at bitterly high cost. These battles were among the most brutal of the war, and clearly indicated that any conventional invasion of the Japanese home islands – designated Operation Downfall – might take millions of Allied and Japanese lives to complete. Nor was there any way to predict how long such a fight would last.
Okinawa and Iwo Jima were savage, close quarter engagements that demonstrated the zeal of Japanese resistance. It made a deep impression on how much the Japanese were prepared to sacrifice, their utter rejection for the concept of surrender, and how that may manifest in defense of their home islands.
During the war itself, the Allies held between 20,000 and 50,000 Japanese prisoners of war. Compared to the estimated 140,000 Allied POWs held in captivity by Japan. Long story short, surrender was a rare occurrence by Japanese forces. By comparison, the UK and Britain each held roughly 400,000 European Axis POW’s during the war. Japan was the unambiguous exception among all belligerents involved in the conflict.
Unless otherwise instructed to surrender by Emperor Hirohito, or ranking government officials, Allied leaders had legitimate reason to fear that every Japanese man, woman and child may have fought to their extinction against any such invasion of mainland Japan.
Within the context of the greater war, the Japanese rejection of surrender was remarkably unique, entirely foreign to Western sensibilities, and in fact almost otherworldly in the eyes of the American and British troops locked in combat against them.
During the fighting in the European or North African theaters, surrender was far more commonplace and mostly accepted by all sides – despite the treatment of POW’s varying significantly. Seldom was there such a constitutional elan to avoid being taken prisoner at the cost of one’s own life. Even for the soldiers of the Red Army that sought to avoid surrender at all costs, their attitude was predicated on their expected treatment by the Germans in captivity, and the understandable dread of later repatriation to the USSR should they survive their captivity. Never was it treated as a divine mandate – as it so clearly was for the Japanese.
Yet while the Allies understood the implacable nature of Japanese resistance, accompanied with their aspirations for the potential of their new atomic bombs, they were not at all certain about the atomic bombs reliability. Nor was anyone placing bets that the bombs use might bring a swift end to the war despite their greatest hopes.
The Atomic Bomb was no Golden Ticket
A common popular trope that’s become wound up in the history of the atomic bomb’s usage is the ahistorical belief that it would invariably promote immediate Japanese capitulation. Furthermore, it’s often retrospectively assumed that the Allies thought they were near victory in August 45’.
Allied leaders in the summer of 1945 had no clear expectations that the atomic bomb’s use would necessarily force an end to Japan’s fight whatsoever. When peace transpired in August 1945, it genuinely caught the Allies by surprise.
Nor could Allied war planners have proceeded from such an assumption, as it would have hindered preparation for what they thought was the likely course of action regardless: a conventional invasion of the Japanese home islands.
Furthermore, it’s critical to note that Japan did not outwardly flinch initially following the first atomic bomb’s use on Hiroshima. It was not until the second atomic bomb was dropped on Nagasaki, accompanied by the Soviet invasion of Manchukuo (Manchuria), that Hirohito broke the Imperial War Council’s deadlock over the decision to surrender.
Japanese surrender – when it eventually came forth – was a major shock to the Allies for several reasons. It was unknown how much the atomic bombings might have impacted the thinking of Japanese war planners or Hirohito himself. Or that dropping the atomic bombs might lead to his uncharacteristic unilateral intervention to ending hostilities.
Moreover, there was sound and reasonable doubt that the bombs would function at all. The Allies had only the bomb’s first successful test detonation in July 1945 from which to proceed. One could never reasonably place all their bets on a revolutionary technical advancement, especially after only a single successful test.
Nor were the Allies altogether ready for peace. The Allies were planning for the war against Japan to last into 1946 or 1947 at the earliest.
Was the Use of the Atomic Bombs Inevitable?
As a rule, nothing in history can be thought inevitable… except for a German counter-attack. Though when one examines the numerous factors that lead to the Allies first developing, and then using atomic bomb; including the financial cost of doing so, it’s various intra-governmental as well as domestic political implications, and its potential strategic magnitude while fighting a global conflict, it’s nigh impossible to imagine the Allies choosing otherwise.
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Suggested Reading:
- “Hell to Pay: Operation Downfall and the Invasion of Japan, 1945-1947” by D.M. Giangreco
- “Retribution: The Battle for Japan, 1944-1945” by Max Hastings
- “Truman” by David McCullough
Suggested Viewing:
- ”Kamikaze” (1995), BBC Timewatch
Outline of the never attempted Operation Sea Lion, the proposed invasion of the British Isles by Nazi Germany – September 1940
“Why didn’t Germany follow through with Operation Sea Lion and invade Britain? The British were completely exposed, and it seems like it would have made a lot of sense at the time.” – Jordan, Edinburgh
This question pervades historical quandary far and wide. The first question you must address is did Nazi Germany have the resources to invade the British isles in 1940? Better known as Operation Sea Lion (German: Unternehmen Seelöwe).
As devastating as May and June 1940 was for the French and British, Germany had an incomplete set of strategic means to fight the kind of war an amphibious invasion of Britain required. Nor did Hitler have the fundamental political inclination for such a fight, which is where answering this question begins.
Hitler, the British & the War He Never Wanted With Them
Hitler in his infamous political manifesto Mein Kampf spoke very highly of the British and their global empire at the time of its writing. Hitler saw the British as racially kindred to his so-called Aryan race, and admired their acquisitive track record over the past 500 years – especially in India.
Hitler in the early years of his rule embarked on a major diplomatic initiative to establish a formal alliance with the British. Hitler’s envisaged alliance sought to achieve two primary aims:
• Establishing recognition of German hegemony over Eastern Europe, perfectly complimented by the British command of the seas and their foreign colonies. In Hitler’s view neither Nazi Germany nor the British could command both arenas, seeing the desired co-operation as a natural and realistic arrangement.
• Recruiting a chief ally in his great self-acclaimed providential purpose, the destruction of the Soviet Union, and creation of German “Liebensraum” in Eastern Europe and Eurasia.
Hitler abjectly failed on both accounts, however his ambivalence for war with the British Empire persisted. The grand strategic assessment by Hitler was that Germany had historically been a continental power, and he planned his course of action for conquest accordingly.
Moreover that ambivalence for military conflict with the British lead to Germany never seriously preparing for a war that would include the mammoth task of invading the British Isles. It would later have immense consequences for Germany prosecuting the war.
With France’s stunning collapse in June 1940, and the resulting German hegemony on the continent left it in a position Hitler did not seriously anticipate: British obstinance in continuing the war.
Hitler viewed the war as effectively over at the end of June 1940, which for all practical purposes it was given no British forces were then fighting on the continent itself. Hitler thought that with the fighting in Europe at its conclusion, the British would certainly make the practical decision to come to terms with Germany, formally ending the war. It did not.
With this in mind, exactly what would have German forces needed to accomplish to successfully invade Britain in Operation Sea Lion?
The Minimum Requirements for Germany to Successfully Invade Britain in Operation Sea Lion
For Germany to cross the English Channel, a feat too great for even Napoleon a century prior, it was necessary to fulfill several main objectives to give such an assault a plausible probability for success. The following are some of the major prerequisites for Operation Sea Lion:
• Achieve air supremacy over the skies of southern England by crippling the RAF, simultaneously protecting the invasion beaches, and facilitating the bombing of critical inland targets.
• Secure the easternmost and westernmost approaches to the English Channel, thwarting the British Homefleet from heavily damaging – if not annihilating – incoming invasion waves and logistical support.
• Ensuring the continuous flow of troops, armor, heavy weapons platforms, fuel, and general supplies to the invasion beaches.
• Successfully gaining footholds on the southern English invasion beaches, and breaking out inland.
• Utilizing the extremely limited window in September 1940 that presents the most favorable weather conditions required for crossing the notoriously temperamental English Channel.
The aerial campaign known as the Battle of Britain was the foremost step to enact any possible invasion of Britain in 1940. The British Royal Airforce’s (RAF) victory during the battle, while genuinely tremendous, has fallen into the popular fallacy that it prevented the invasion of Britain.
Germany certainly required air supremacy to have any chance for a successful invasion of Britain, it is true. The Luftwaffe’s failure to do so however was far from the sole reason Sea Lion was stillborn upon original conception.
So with these qualifications for invasion in mind, what was Hitler to do with the last major enemy belligerent in his war. Realistically, Germany had limited means to force the peace Hitler desired. Germany’s limitations for Sea Lion were none more pronounced than its surface blue water naval capabilities.
Nazi Germany on the High Seas
For all intents and purposes, Germany went to war several years too early to seriously challenge the British or French in naval surface warfare. Unlike the formidable Imperial German High Seas Fleet during the Great War, Nazi Germany did not possess nearly the same numbers in their surface naval forces. Moreover, despite all of their military misfortunes fighting on the continent itself in 1940, Britain was still the world’s foremost naval superpower.
Plan-Z was the Kriegsmarine’s – German Navy – construction plan to create a blue-water rival of the Royal Navy. The caveat to their plans however was that it was not projected for completion until 1943 at the earliest, four years after Hitler plunged Europe into war.
The lack of a formidable surface naval presence made any cross channel operations invading Britain from northern France or Belgium dubious, as Germany could not challenge the onslaught of the formidable British Homefleet.
The Royal Navy’s Homefleet was stationed at Scapa Flow in Scotland, and was chosen as the best area to coordinate and execute the naval blockade of Germany as was also conducted in the First World War. In case of an invasion, the Homefleet could have responded to any cross channel invasion within a day – entirely outclassing their invading enemy, and unceremoniously halting Sea Lion in its tracks.
Nor did Germany have anything approaching adequate purpose built landing craft; similar in nature to the Allied Higgins boats (LCVP) deployed later in the war, that would be indispensable for undertaking any variation of Sea Lion.
When Operation Sea Lion was hastily being planned and assembled following the defeat of France in June 1940, Germany appropriated continental riverboats, various barges, small commercial fishing vessels and tugs intending to create ersatz invasion landing craft. Theirs was a paltry attempt for overcoming their lack of strategic capabilities for undertaking their amphibious assault in Operation Sea Lion.
With a lack of purpose built landing craft, the Germans couldn’t reliably ferry its forces to the beaches. Additionally, the Kriegsmarine’s wanting surface vessel presence couldn’t protect the sea lanes to the invasion beaches located in southern England. Therefore they would not have been able to sustain the logistical and reinforcement support any invasion force requires – if they managed to land forces at all.
“[l]ogistics is the ball and chain of armored warfare” – General Heinz Guderian
Heinz Guderian, one of the key figures in developing German combined arms warfare doctrine – “Blitzkrieg” – once stated, “[L]ogistics is the ball and chain of armored warfare.” His military planning truism was front and center in any conception of Sea Lion, as invasion forces would require the continuous replenishment of all the materials necessary to continue fighting without interruption.
To further compensate for German naval inferiority vis-à-vis the Royal Navy, the Luftwaffe was saddled with bombing British vessels to help prevent their breaking into the Channel invasion lanes, and running roughshod.
During the Dunkirk evacuation, the Luftwaffe sank six British destroyers and 200 crafts overall. Though attempting to sink Royal Navy vessels at sea poised for combat, that were not simultaneously occupied with a major evacuation was a different prospect entirely. Nor were they orders to be relished by even the most gung-ho Luftwaffe pilot. It was but another element in striving to compensate for Germany’s naval deficiencies.
Overall, the dearth of proper resources for such an attempt blatantly belies the fact that Hitler never seriously considered invading and occupying the United Kingdom.
Germany’s lack of adequate naval presence would have been a trump card. Nor was the Wehrmacht itself designed with an amphibious invasion the likes of Sea Lion in mind.
Hitler still possessed that same continental view of German power, at least by that juncture in the war, and crossing the English Channel was not something the Wehrmacht was either trained or equipped for in the least. Moreover, there was significant internal discord over the specifics of Operation Sea Lion itself.
Wehrmacht vs. Kriegsmarine: Fighting the Allies and Each Other
When it came to planning Sea Lion at the proverbial map table, the Kriegemarine and Wehrmacht had serious disagreements. Both parties did not see eye-to-eye on the best way to invade Britain.
The Wehrmacht envisaged Sea Lion occurring on a broad front, stretching from Dover to Lyme Regis. The first and second wave of invasion forces coming ashore were comprised of
• 6 infantry divisions
• 1 specialized Mountain division
• 1 SS motorized regiment
• Motorized Großdeutchland regiment
• 2 Panzer divisions
• 1 division of Fallschirmjäger (Paratroopers) covering both the westernmost and easternmost flanks of the invasion force.
The entirety of Sea Lion’s initial assault wave was to include a landing totaling 67,000 men. Sea Lion therefore was composed of a little more than one-third of D-Day’s initial phase of landing forces.
The Kriegsmarine conversely insisted on an invasion over a more narrow front, based on its limited naval assets being unable to support an invasion of the Wehrmacht’s proposed scope.
In discussing Operation Sea Lion, the perennial elephant in the room is how it stacks up against later Operation Overlord. As both sought to achieve the same aim, albeit in opposite directions, it is an unavoidable comparison.
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Operation Sea Lion vs. Operation Overlord
The best method to weigh this scenario is by comparing Operation Sea Lion to the Allied qualifications for launching Operation Overlord, or D-Day in June 1944.
Qualifications for Launching D-Day:
• Achieving air superiority by defeating the Luftwaffe, and ensuring the Allies firm control over the skies of Western Europe.
• Prevail in the Battle of the Atlantic, allowing the vital transatlantic supply lines to function unimpeded from U-Boat raids, thus ensuring the operational artery indispensable to support the cross-channel invasion.
• Through the auspices of Operation Bolero beginning in early 1942, the continuous staging of US Army divisions, military equipment and supplies in Great Britain over two years for the eventual expected Allied invasion of northwest Europe.
• Accumulating overwhelming naval support to ferry, protect and support the invasion forces landing on the beaches of Normandy. The specific tasks included, but were not limited to, providing continual logistical support, medical support, providing artillery bombardment and ensure cover over the invasion beaches.
• Design, manufacture and deploy the necessary Higgins boat (LCVP) landing craft – always seemingly in short supply – to safely ferry combat units to the beach. In addition to constructing a formidable number of Liberty ships to ferry the invasions heavy equipment, armor, and related equipment for both the initial landing assault on Normandy, and their reinforcements.
• Design, construct and deploy two Mulberry Harbors to facilitate refueling needs for the largely mobile Allied Expeditionary Force.
• Build and deploy PLUTO – Pipeline Under the Ocean – a large pipe laid on the bed of the English Channel to send patroleum to France that was 130km (or 70nMi).
• Training the Allied armies for many months to handle the unique challenges of amphibious invasion, as well as the expected carnage that fight would require. (Note: The U.S. Marine Corps – the branch uniquely qualified to conduct amphibious assaults – were largely absent from D-Day, being mostly deployed in the Pacific)
These are but a few of the major points of strategic necessity to make the invasion of Western Europe across the English Channel possible, and the Germans possessed almost none of those abilities in 1940 for Sea Lion.
“On land, I’m a hero. On land, I’m a coward.” – Adolf Hitler
According to German general Franz Halder, head of the OKH in his personal diaries, Hitler spoke to his inner circle about making a peace “She [Britain] felt honorable.” Hitler and his admiration for the British is well documented, but these sentiments were also the product of the fact Hitler was neither seriously interested in invading Britain, and recognizing the absence of that possibility. According to Halder’s diaries Hitler famously stated, “On land, I’m a hero. On water, I’m a coward.”
There are a great many factors that went into this equation, and there is every reason to believe that such an invasion as Operation Sea Lion would have been a disaster.
Churchill, in the estimation of his co-biographers William Manchester and Paul Reid in The Last Lion: Defender of the Realm 1940-1945, never seriously believed that a German invasion was a realistic possibility, recognizing Germany had no bridge across the sea.
Churchill as a wartime PM sought to ensuring the best preparation possible at home should it happen beyond all expectations, in addition to keeping British minds and hearts focused on the long term objective of winning the war.
In total this casts the eventual alternative to Operation Sea Lion Hitler chose to challenge the British further, the Blitz, in a new light.
Hitler’s Inadequate Alternative to Operation Sea Lion & His Greater Ambitions
Hitler in late 1940 was faced with the strategic reality of an inability to achieve a peace with Britain, or invade the British isles, ultimately settled on the subsequent Blitz.
As incredibly destructive as the Luftwaffe nighttime bombing campaign was in Britain through the end of 1940 and early 1941, it was a strategic contingency plan; the purpose of the Blitz aimed to break British domestic morale and force a change in government. Presumably that successor government would agree to the accommodation Hitler sought.
The Blitz not only failed to break the resistance of the populace, it had the opposite effect by making the British people more implacable in their will to continue the war against Germany.
The Blitz without question was not an act of German military superiority, but a demonstration of the limits of German power and capabilities – serving as less than a half-measure to defeat Britain. Moreover, it was also surely the result of Hitler’s much grander ambitions growing in the East.
The Seeds of Barbarossa
As the fall of 1940 came and went after defeat in the skies of Britain, lacking a bridge across the sea to follow through with Operation Sea Lion, with no prospect of peace with the British, Hitler’s true focus shifted east over the European map. Hitler thought it time to begin preparations for invading the Soviet Union. Hitler proceeded to issue Führer Directive No. 21 in December 1940 – that would culminate with Operation Barbarossa in June, 1941.
Now you know the rest of the story.
Do you have a question you want to answer about WW2? Email the Brain Bucket!
Suggested Reading:
• “The Storm of War: A New History of the Second World War” by Andrew Roberts
• “The Last Lion: Defender of the Realm 1940-1945” by William Manchester & Paul Reid
• “The Second World Wars: How the First Global Conflict was Fought and Won” by Victor David Hanson
• “The Battle of Britain: Five Months that Changed History May-October 1940” by James Holland
Recommended Viewing:
• “Hitler and the Invasion of Britain” (1998), BBC Timewatch
Write to Paul K. DiCostanzo at pdicostanzo@tgnreview.com
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