America and Nazi Germany Waged an Undeclared Naval War Way before Pearl Harbor

America and Nazi Germany Waged an Undeclared Naval War Way before Pearl Harbor

The facts make it clear. 

Between September 1939 and December 1941, the United States moved from neutral to active belligerent in an undeclared naval war against Nazi Germany. During those early years the British could well have lost the Battle of the Atlantic. The undeclared war was the difference that kept Britain in the war and gave the United States time to prepare for total war.With America’s isolationism, disillusionment from its World War I experience, pacifism, and tradition of avoiding European problems, President Franklin D. Roosevelt moved cautiously to aid Britain. Historian C.L. Sulzberger wrote that the undeclared war “came about in degrees.” For Roosevelt, it was more than a policy. It was a conviction to halt an evil and a threat to civilization. As commander in chief of the U.S. armed forces, Roosevelt ordered the U.S. Navy from neutrality to undeclared war.

It was a slow process as Roosevelt walked a tightrope between public opinion, the Constitution, and a declaration of war. By the fall of 1941, the U.S. Navy and the British Royal Navy were operating together as wartime naval partners. So close were their operations that as early as autumn 1939, the British Ambassador to the United States, Lord Lothian, termed it a “present unwritten and unnamed naval alliance.” The United States Navy called it an “informal arrangement.”

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Regardless of what America’s actions were called, the fact is the power of the United States influenced the course of the Atlantic war in 1941. The undeclared war was most intense between September and December 1941, but its origins reached back more than two years and sprang from the mind of one man and one man only—Franklin Roosevelt.

Two Navies Unprepared For War

When war broke out in September 1939, the Royal Navy and the German Kriegsmarine were both unprepared. Land-minded Adolf Hitler prepared his army and air force but had not given his navy time to build the necessary submarine or surface fleets for a naval war against Britain. Since Hitler planned for a war of short duration, he considered interference with the Atlantic sealanes a means to defeat Britain. However, Hitler preferred to eliminate continental powers first and then make the British “see reason.”

The German naval staff, led by Grand Admiral Erich Raeder, and the U-Boat Service, commanded by Admiral Karl Dönitz, held the opposite view of the war. They were convinced it would be a long war and that it would have to be won in the Atlantic. The Kriegsmarine believed that Britain had to be hit decisively in the Atlantic theater before America’s power and economic impact became decisive. Dönitz believed that 300 submarines and wolfpack tactics could strangle Britain. But Hitler launched the war almost three years before the naval construction program was completed. This left the German Navy short of submarines and surface vessels. At the start of the war, Hitler also restricted the U-boat campaign.

The British instituted the convoy system at the start of the war. First Lord of the Admiralty Winston Churchill remembered the lessons of World War I and reestablished the convoys. However, the Royal Navy engaged in the war sooner than they hoped. The British shipbuilding program, especially escorts, would not produce results until 1941. Until the new escorts came on line, a convoy escort limit had to be drawn about 300 miles west of the British Isles.

The British convoys had four major weaknesses: (1) a shortage of escorts, usually two or three ships; (2) ASDIC (a method of underwater detection) was ineffective beyond 1,000 yards; (3) RADAR (improved detection) was too primitive to give early or accurate warnings of night attacks; and (4) lack of air cover. As much as the Royal Navy lacked at the start of the war, it did have the capacity to blockade Germany, bottle up most of the German surface fleet, and handle the few U-boats and raiders that operated on the high seas.

But Churchill, unlike Hitler, recognized that the war would be a long, total war. As such, he saw the escort shortage as a major weakness. Churchill thought Roosevelt might be persuaded to sell Britain fleet destroyers to fill the urgent need for open-ocean escorts for convoys and inquired about such an arrangement in September 1939. The situation at the outset was decidedly in favor of the Allies.

America’s Inevitable War

The Munich Pact and the failure of appeasement convinced Roosevelt that Germany remained a dangerous threat and that war was inevitable. Roosevelt’s policy for America was dictated by a desire to stay out of war, support the Allies, and prepare America’s defenses. Gerhard Weinberg, in A World at War, wrote, “The American President hoped to avoid open warfare with Germany altogether. He urged his people to aid Britain and he devised a whole variety of ways to do just that; but he hoped until literally the last minute the United States could stay out of war.”

Secretary of State Cordell Hull supported FDR’s position by stating, “Our highest military officers repeatedly said they needed time to prepare our defenses.” Thus, the longer FDR could delay American participation in a shooting war, the better prepared the United States would be. Roosevelt’s basic approach was to do as much as he could for Britain and France without incurring the wrath of American isolationists or driving Hitler to a declaration of war. Roosevelt had the ability to do this.

Admiral Samuel Elliot Morrison described FDR’s strategy: “The President had a political calculating machine in his head, an instrument in which Gallup polls, the strength of armed forces and the probability of England’s survival; the personalities of governors, senators, and congressmen; the personalities of Mussolini, Hitler, Churchill, Chiang, and Tojo; the Irish, German, Italian, and Jewish votes in the approaching election; the ‘Help the Allies’ people and the ‘American Firsters,’ were combined into the fine points of political maneuvering.”

All of these abilities enabled Roosevelt to influence American public opinion while guiding U.S. foreign policy. Roosevelt recognized Great Britain as the front line in America’s defense against Nazi Germany.  Even the Times of London termed his position on the Atlantic “a forward strategy despite a neutral status.” However, it was clear that this policy could only be maintained by armed resolution. Since this was to be a forward defense, reaching far into the Atlantic, then the only tool America had was the U.S. Navy.

Projecting Power with the U.S. Navy

The U.S. Navy stood as the shield guarding America. Now the Navy would not only protect the United States but would also project American power into another European war. Roosevelt would use the Navy to test the purposes of the Führer. When Roosevelt realized Hitler was unwilling to confront U.S. policy, the president set to work.

Roosevelt created his instrument in January 1939. In that month he ordered the formation of the Atlantic Squadron. At the time of the Munich Pact, the Atlantic naval strength consisted of just seven cruisers and seven destroyers. With a shift of vessels from the Pacific to the Atlantic, the Atlantic Squadron was born. By the time war broke out in Europe, the squadron consisted of an aircraft carrier, four battleships, a cruiser division, and a destroyer squadron. Roosevelt planned a new role for the enlarged Atlantic force.

Back in the spring of 1939, Roosevelt had informed cabinet members of his plan to inaugurate a naval patrol extending from Newfoundland to South America. In May 1939, under conditions of utmost secrecy, the British Admiralty dispatched a planning officer to Washington to discuss Anglo-American naval dispositions in the event that Britain found herself at war with Germany. In the discussion, it was agreed that “command of the western and southern Atlantic would have to be assured by the United States Fleet.”

In June, at a meeting between the president and King George VI, Roosevelt told the king about the help he planned to give Britain in the event of war. The president sketched his ideas of a Western Atlantic patrol based in Trinidad and Bermuda that would fan out along a radius of 1,000 miles by sea and air. Here Roosevelt’s vision projected almost two years into the future. A few weeks later, in July, Roosevelt secretly but directly proposed to the British Foreign Office that the United States should establish a patrol over the Western Atlantic.

An “American Closed Zone” in the Atlantic

Two days after England and France declared war on Germany, the president ordered the U.S. Navy to organize neutrality patrols. The president also declared a neutrality zone, initially a 300-mile wide strip of ocean along the East Coast of the United States running south through the Caribbean. The object of the patrols was to report and track any belligerent forces approaching the coasts of the United States or the West Indies. The Germans immediately saw that the zones contracted the area in which their commerce raiders could hunt.