The German threat: Plan Dog

US strategy

Eric Rauchway


April 13, 2023

On November 12, 1940, shortly after Roosevelt’s re-election to a unique third term in the presidency, Chief of Naval Operations Harold Stark sent a memorandum to the Secretary of the Navy, Frank Knox, outlining the US military position. The document became known as “Plan Dog,” after the US-UK phonetic alphabet for “D” (Able, Baker, Charlie, Dog, Easy, Fox, etc.) because out of the options Stark considered, he recommended proceeding with the one he lettered “D”—a joint offensive with Britain against Germany in the Atlantic, in anticipation of a wider war.

Admiral Stark, in the light gray business suit, stands behind the president, who is decorating Admiral Yarnell for his recent comportment in China. Photo of August 28, 1939. Library of Congress.

The memorandum runs 26 pages and covers a lot of ground. Here is a single paragraph, from page 19, where Stark gives a succinct summary of his argument for US concern about the German threat.

It is a fundamental requirement of our military position that our homeland remain secure against successful attack. Directly concerned in this security is the safety of other parts of the Western Hemisphere. A very strong pillar of the defense structure of the Americans has, for many years, been the balance of power existing in Europe. The collapse of Great Britain or the destruction or surrender of the British Fleet will destroy this balance and will free European military power for possible encroachment in this hemisphere.

The security of the US depends on the security of the Americas; the security of the Americas depends on a balance of power in Europe; German defeat of Britain will end that balance and its destruction or acquisition of the British fleet would enable a German attack on the Americas and thus imperil the United States.

We know Hitler thought in similar, if reversed, terms, planning a war on the United States once he had secured his European triumph, though he did not necessarily feel he needed to defeat Britain—merely the Soviet Union, which he expected to do swiftly.

Stark thus believed the first question was how best to preserve Britain from defeat. He rejected focusing on likely war with Japan, or strictly defensive options, and advocated his option D: a joint offensive with Britain in the Atlantic, while keeping a strong defensive posture in the Pacific. The US fleet should remain in the Pacific until war was “imminent.” Assistance to Britain would mean protecting shipping in the western Atlantic, and reinforcing British naval operations around the British Isles and down the coast of Africa, as well as in the Mediterranean.

The chief of naval operations further acknowledged that “purely naval assistance, would not, in my opinion, assure final victory for Great Britain,” and moreover that Britain lacked the manpower to win an infantry campaign on its own. “I believe that the United States, in addition to sending naval assistance, would also need to send large air and land forces to Europe or Africa, or both, and to participate strongly in this land offensive.”

Any other option, Stark believed, would end in British collapse—and thus a serious threat to US security.

The memorandum thus recommended joint Army-Navy plans and moreover, “secret staff talks on technical matters with the British military and naval authorities” to assure coordination of the impending war effort.

The Army accepted Stark’s memo with the addition that the United States should expect to supply substantial air support in a war alongside the British. The president authorized the staff conversations, and on December 2, 1940, Stark invited the British to come to Washington for joint planning.1


  1. Stetson Conn and Byron Fairchild, The Western Hemisphere: The Framework of Hemispheric Defense, vol. 12, part 1, United States Army in World War II (Washington, D.C.: Office of the Chief of Military History, 1960), 92.↩︎