Frequently Asked Questions

Why did you write this book?

As a teenager on a canoe trip, I learned about Roosevelt’s secret fishing trip in the same area of Canada only weeks before his August 1943 summit with Churchill. Time and again, during 40 years of supporting the intense work of national security policymaking, I would wonder how FDR could have taken off to go fishing at such a critical moment for the setting of Allied strategy for World War II. So, in retirement, I began to dig. Sure enough, a good story emerged.

What surprised you the most?

The biggest surprise did not come from within Advocating Overlord, but from how much the world changed over the eight years I spent researching and writing the book. When I began research in earnest in 2010, the international framework for security and cooperation, that first took root in the mid-1940’s was under pressure but healthy, providing a good basis for facing the future. By 2018, when Advocating Overlord was released, all of that was under serious challenge. On both sides of the Atlantic, resurgent ethno-nationalism and authoritarian populism are combining to cast over democracy shadows of a kind not seen to be so dark since the 1930’s. Concurrently, again on both sides of the Atlantic, the structure of international cooperation is being torn at by resentment and suspicion very similar to that which made trust between allies so difficult to restore 76 years ago. From that, I see two messages for our time in Advocating Overlord. The first is a warning: relationships between allies whipsawed by misunderstanding and narrowly-based grievances cannot – even in the face of an existential threat – be restored to cooperation just by throwing a switch. But second, an encouragement: new leaders with the courage to reject division can unite and act to make the impossible possible, as COSSAC’s “happy few” did so well in 1943.

Why focus on the year 1943?

By the start of 1943, the Allies had succeeded in ending the threat of their defeat by the Axis powers of Germany, Italy, and Japan. They could begin serious planning for military victory. The burning question for the Allies was, win in Europe by what strategy? Coming to agreement on the answer was difficult. In the background, American political and military leaders' thinking about the foundation of U.S. national security strategy evolved between January and November away from isolationism-based hemispheric defense to accept a permanent role for the United States as a global power. Concurrent with but separate from the strategy debate, Anglo-American information sharing to develop an atomic bomb broke down. The two issues, strategy and atomic cooperation, gradually became intertwined at the top.  The interplay between these factors, so influential on events right up to our time, makes 1943 a very interesting year to study.

What was OVERLORD?

OVERLORD was the name adopted in May 1943 for the Allied operation to thrust across Northwestern Europe into the heart of Hitler's Third Reich and, together with Soviet armies advancing from the east, defeat the Nazis totally. OVERLORD was planned to begin with an assault across the English Channel (La Manche) to land on the coast of France.

D-Day happened on June 6, 1944, but the book refers to May 1, 1944. Why?

The target date agreed for beginning the cross-Channel assault to launch OVERLORD was May 1, 1944, and that date held throughout 1943, the time frame for most of the events in the book. In January 1944, the newly-appointed Supreme Allied Commander, General Eisenhower, ordered a review of OVERLORD planning. This led to an increase in the required number of Allied forces for the attack, something the planners had wanted all along, and an expansion of the landing beaches. To mount this larger operation, the date for the start of OVERLORD was moved to June 1944.

So, OVERLORD was more than the Normandy Invasion?

Yes, the Normandy Invasion, or D-Day and its supporting activities, was Operation NEPTUNE. Vast though it was, NEPTUNE was just the first phase of OVERLORD but, one of critical, make-or-break importance.

What is the map in the background of the webpage?

Near the end of July 1943, COSSAC’s "OVERLORD Outline Plan" was ready to be delivered to the Combined Chiefs of Staff. The plan demonstrated that a successful landing on the Normandy coast was feasible with the limited force that the Chiefs had allotted.  With a viable plan in hand, resistance fell away and the OVERLORD strategy was accepted. Included in the July 1943 plan was this hand drawn concept for an initial landing of three divisions on three beaches and one landing ground.  In January 1944, the size of the force and the number of beaches and landing grounds was increased to the operation that took place on June 6, 1944, D-Day.  The book includes a map that compares D-Day as proposed in July 1943 and as carried out in June 1944.

The book stops at the end of December 1943. What happened between then and D-Day, six months later?

By the end of 1943, the advocates for OVERLORD had won commitment to the operation irrevocably and the effort to assemble in the United Kingdom the forces for the cross-Channel assault (NEPTUNE) was well under way. Completion of that vast enterprise occurred over the months between the end of 1943 and D-Day.

Why did the American military leaders want OVERLORD while the British did not?

The positions of the American and British military leaders reflected their contrasting national situations, resources, history, and strategic outlook. As a maritime power with global interests and obligations, the historic British-preferred response to a land conflict in Europe was blockade and attrition of the enemy. In the 20th century, this strategy was expanded by adding air bombardment and reinforced by a desire not to repeat the horrific bloodletting of World War I. All of these factors combined to encourage Churchill and the British Chiefs of Staff to prefer what the British and Americans both termed an “opportunistic strategy” of contingency response to an induced political-economic collapse of Germany. The American military chiefs came into the war banking on mobilization and projection overseas of tremendous resources for quick victory through a direct, violent assault to defeat the most threatening enemy, the Nazis, pivoting to the Pacific to defeat Japan, and then going home to demobilize as was done after World War I. That last goal would give way in 1943 to recognition and embrace of a new, permanent role for the United States in the world.

The strategy arguments were fierce. How did they reach agreement on anything?

A common enemy was a strongly unifying factor. But, an interwar legacy of bias and misperception in both countries made agreement difficult. One useful tactic was to clear the room of all but the two countries’ military chiefs, who then would go into totally off-the-record “discussions.” The prerequisite for agreement, finally recognized and accomplished, was reestablishing trust. That strong personalities with strong opinions, nevertheless, reached agreements, and implemented them for the common good, is a lesson for our time.

Was it only the Americans who wanted OVERLORD?

No, the planners in COSSAC, under the command of a British general, were an Allied team that was unified and committed. The concept for the strategy and operation that became OVERLORD had support from some important British military and political leaders from the outset. By the end of July 1943, COSSAC had won support for OVERLORD from British and Canadian officers, as well as American, who would hold commands on D-Day.

What was “COSSAC”?

The name for OVERLORD’s Allied planning team was this acronym derived from the first letters of the title of its commander, Lieutenant General Frederick Morgan (later knighted). He was appointed Chief of Staff to the Supreme Allied Commander (designate). COSSAC worked in London, starting in April 1943, to plan the cross-Channel assault and other related operations. The organization was the forerunner of the staff that General Eisenhower would form when he became the Supreme Allied Commander. In the run-up to D-Day, COSSAC was blended into the Supreme Headquarters Allied Expeditionary Force (SHAEF).

What were “Tube Alloys” and “S-1” and how do they relate to the Manhattan Project?

Tube Alloys and S-1 were, respectively, the British and American shorthand codenames for the project to develop the atomic bomb. Tube Alloys, intended to be a deceptive term from its inception, had no other meaning. S-1 had been a section in the organization of the White House Office of Scientific Research and Development (OSRD) out of which some of the early atomic discussions with the British had been managed. The American’s Manhattan Project encompassed the hands-on research, engineering, testing, and production of the first atomic bombs.

The book talks about the “atomic bomb” but, today, we talk about “nuclear weapons. What’s the difference?

World War II was a time of scientific developments in the midst of war and, naturally, usage of language evolved. Tube Alloys, S-1, the Manhattan Project, all were focused on exploiting the enormous release of energy from the splitting – fission - of the atom. For the large and heavy weapon that could be built, the only practical means of delivery at the time was a bomb dropped from a heavy bomber. Hence, the wartime focus on an “atomic bomb.” Even then, scientific leaders had begun speculating about the possibility of a “super bomb” in which an atomic bomb would be the trigger for a fusion of nuclear materials in an exponentially more destructive weapon. Today, with more means of delivery feasible through warhead miniaturization, the umbrella term for these means of mass destruction is “nuclear weapons.”

Why did the Americans cut the British out of development of the atomic bomb?

The answer to that has layers.  On the surface (albeit then-classified) the practical argument made and told to the British scientists by American scientists, notably Dr. James Conant and his boss Dr. Vannevar Bush, was as follows. By late 1942, they concluded, the Americans were making 90 percent of the investment and doing 90 percent of the work and that the British were incapable of developing an atomic bomb on their own in time to affect the outcome of the current war. Therefore, the Americans decided and stated to their British counterparts that there was a lot of atomic science information from the project that the British scientists did not “need to know” to fulfill their obligation to the project.  Beneath the surface, a deeper U.S. motivation, not shared but suspected by the British, was fear about the postwar atomic future that stimulated reluctance to share the secrets of atomic weaponry with any other nation.  Related to that was the U.S. scientists' concern about sharing that might exceed the limits of FDR's Congressionally-granted war powers. Combined, that caused Conant and Bush to advocate a restrictive national security policy on sharing knowledge about the bomb with any country other than their own. Supported by the military commander of the Manhattan Project, Brigadier General Leslie Groves, they made clear to FDR that they would not relax that restrictive position unless ordered to do so by the President.

How did British scientists take this? Couldn’t the British develop an atomic bomb on their own?

The British scientists, who had made important early nuclear discoveries, quickly suspected the Americans of holding to a deeper motive. They made urgent appeals to Churchill to take up atomic access with Roosevelt. Churchill saw that possession of the atomic bomb would be essential to Britain’s postwar independence and he made appeals to FDR. But, during the war, he also was inconsistent in his support for financing British atomic science. Partly for that reason but also because of generally heavy demand by early 1943, Britain was short of resources to pursue its own bomb and still support the conventional forces needed to fight World War II. The available nuclear material already had been cornered by the United States and the diversion of British funds, electricity, steel, and skilled workers to design and build an atomic bomb would have crippled Britain’s war production.

Tell me about the painting on the book jacket

Thomas Hart Benton’s painting "Embarkation: Prelude to Death," which he completed in New York in 1943, perfectly complements the book in two ways. The painting is an evocative, literal depiction of the 1943 surge of American troops to Europe, most of whom embarked from New York. "Embarkation" also offers a visual metaphor, not least for its combination of anxiety and determination, that I hope Benton would allow this author. Nineteen Forty-three was the year in which American leadership, sobered by but accepting the human cost, took action to turn away from isolationism, take up the responsibilities, and embark on permanent engagement in the world.


“Very well-written and very well-researched in British and American archival and manuscript materials as well as published works, Philip Padgett’s Advocating Overlord: The D-Day Strategy and the Atomic Bomb provides a detailed analysis of the Anglo-American disagreements over both European strategy and atomic sharing during World War II. In doing so it offers a provocative, fascinating reinterpretation of the relationship between the two disputes.”

Mark Stoler
author of Allies and Adversaries: the Joint Chiefs of Staff, the Grand Alliance, and U.S. Strategy in World War II and The Politics of the Second Front

“Padgett has provided us with an excellent, extremely insightful study of the pivotal negotiations during 1943 that determined whether and how the fledgling Anglo-American alliance would solidify to make a significant contribution to the defeat of Nazi Germany and go on to provide the basis for post-war western security.”

Dr. Richard Harding
University of Westminster

“Philip Padgett’s important book sheds new light on Allied planning for OVERLORD, a process that involved not just hard bargaining, but a lot of serious thinking. Even those well versed in the history of the war will find much to ponder here, including the entanglement of OVERLORD with the American effort to exclude the British from participation in the building of the atomic bomb, and the final transformation of America’s international role, away from “hemispheric defense,” and toward enduring global engagement.”

Daniel Moran
co-editor of Maritime Strategy and Global Security

“A verbal Bayeux Tapestry, Philip Padgett’s panorama is a mesmerizing tale of how in 1943 Franklin Roosevelt rebuffed Winston Churchill’s passion for an exclusively Mediterranean campaign and authorized instead the Anglo-American amphibious assault on Normandy of June 6, 1944, meanwhile limiting British participation in development of the atomic bomb.”

Dr. Kenneth J. Hagan
Professor and Museum Director Emeritus, U.S. Naval Academy

“By any measure, the journey during World War II of the United States and the United Kingdom, thrown together by malign forces and, while often diverted by clashing personalities and differing national priorities, gradually accepting the necessity of common action to launch the Allied invasion of northwest Europe, has been exhaustively explored over the past seven decades. However, Philip Padgett has provided a novel roadmap for tracing this familiar story. His Advocating Overlord: The D-Day Strategy and the Atomic Bomb is evocatively written, grounded in authoritative research in British and U.S. sources, and offers an intriguing thesis regarding the nexus of issues that led to OVERLORD.”

Theodore A. Wilson
Professor Emeritus of History, University of Kansas

“In Advocating Overlord, Philip Padgett not only offers a carefully-argued and nuanced account of D-Day and all that went with it, but shows how the apparently unconnected Anglo-American wartime effort to build an atomic bomb informed and sometimes complicated Overlord planning at the highest level. This connectivity is rarely discussed but in Advocating Overlord it becomes the driver of a fascinating account of Anglo-American military planning, politics and diplomacy.”

Dr. Kevin Ruane
author of Churchill and the Bomb in War and Cold War

“From the very first sentence, this is a gripping tale that illuminates the critical transition from World War II into the Atomic Age. Exhaustively documented, this book is a treasure for the amateur and professional historian alike.”

David Wood
Journalist, winner of the Pulitzer Prize 2012

“When thinking about the Second World War, Operation OVERLORD and the Manhattan Project are definitely two major subjects that have received significant attention over the years. However, rarely have these two highly discussed events been handled in a parallel manner. Philip Padgett has written an intriguing history that provides keen insights into the special relationship between the United States and Great Britain as they worked toward the planned Allied invasion of Europe, as well as engineering and construction of the atomic bombs. Simply in Advocating OVERLORD: The Atomic Bomb and the D-Day Strategy Decision, Padgett has written an insightful history of how these two significant events influenced one another within the context of the Second World War, as well as the special relationship between the United States and Great Britain.”

Dr. Sean N. Kalic
author of The U.S. Presidents and the Militarization of Space 1946-1967

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