THERE WERE MANY other British triumphs. One of the most important was Ultra. Ultra was the code name for the system of breaking the German Enigma encoding machine. From 1941 onward, the British were reading significant portions of German radio traffic, giving the Allies a generally accurate, and occasionally exact and total, picture of the enemy order of battle. As that is the most basic and priceless of all intelligence in war—where are the enemy units? in what strength? with what capabilities?—Ultra gave the Allies an immense advantage.

When the Ultra secret was finally revealed in the early 1970s, people asked, “If we were reading German radio traffic right through the war, how come we didn’t win the war sooner?” The answer is, we did.

The intelligence advantage was even greater thanks to the British Double Cross System and to German conceit. In 1940, the British had managed to arrest all German spies in the United Kingdom. They were “turned,” persuaded at the point of a gun to operate as double agents. For the next three years they sent information to their controllers in Hamburg via Morse code, information carefully selected by the British. It was always accurate, as the aim of the operation was to build Abwehr (the German security service) trust in the agents, but was always either insignificant or too late to be of any use.¹⁷

Sometimes the information passed on could prove disconcerting to the Allied forces preparing for the invasion. Sgt. Gordon Carson of the U.S. 101st was stationed in Aldbourne, west of London, late in 1943. He liked to listen to “Axis Sally” on the radio. Sally, known to the men as the “Bitch of Berlin,” was Midge Gillars, an Ohio girl who had wanted to be an actress but had become a Parisian fashion model. There she met Max Otto Koischwitz, married him, and moved to Berlin. When the war came, she became a disc jockey. She was popular with the American troops because of her accent and her sweet, sexy voice and because she played the latest hits, interspersed with crude propaganda (Why fight for the communists? Why fight for the Jews? etc.) that gave the men a laugh.

But they did not laugh when Sally interspersed her commentary with remarks that sent chills up the spines of her listeners, such as: “Hello to the men of Company E, 506th PIR, 101st A/B in Aldbourne. Hope you boys enjoyed your passes to London last weekend. Oh, by the way, please tell the town officials that the clock on the church is three minutes slow.”¹⁸

Axis Sally had her facts straight and hundreds of GIs and Tommies tell stories similar to Carson’s about the clock. Fifty years later, the veterans still shake their heads and wonder, “How the hell did she know that?” She knew because the Double Cross System had given her the information.^III

The receipt of so much information from their agents reinforced the German conceit that they had the best set of spies in the world. That added to their conviction that Enigma was the best encoding machine, absolutely unbreakable, and made them think that they had the best intelligence and counterintelligence systems in the world.

Fooling the Germans about Allied capabilities and intentions was the negative side of the espionage struggle. The positive side was gathering information on the German order of battle. Of course, Ultra was making a priceless contribution here; to supplement Ultra, the Allies had two sources that, at the end of 1943, they were ready to put into full action. The first was air reconnaissance. With the Luftwaffe fighting on the defensive, mostly inside Germany, the Americans and British were free to fly over France and take all the photographs they wished.

But tank and artillery parks could be hidden in woods, field emplacements camouflaged, which brought into play the second Allied source, the French Resistance. Partly to keep the economy producing at full capacity, partly because in France the German occupiers tried to act in a decent fashion in order to make friends, French civilians were not evacuated from the coastal areas. They could see where the Germans were positioning their guns, hiding their tanks, placing their mines. When the time came, they had ways of getting that information over to England, primarily by working with the Special Operations Executive (SOE), a part of the vast British intelligence gathering/covert operations network that was one of the great British accomplishments in the war.

IT IS FAR too simple to say that the marriage of British brains and American brawn sealed the fate of Nazi Germany in the West. The British contributed considerable brawn, for one thing, and the Americans contributed considerable brains. Still, there is some truth in it. If the British miracles of World War II included Hobart’s Funnies, Mulberries, Ultra, and the Double Cross System, the American miracles included production of war matériel such as the world had never seen.

At the beginning of 1939, American industry was still flat on its back. Factory output was less than one-half of capacity. Unemployment was above 20 percent. Five years later unemployment was 1 percent while factory capacity had doubled, then doubled again and yet again. In 1939, the United States produced 800 military airplanes. When President Franklin Roosevelt called for the production of 4,000 airplanes per month, people thought he was crazy. But in 1942, the United States was producing 4,000 a month, and by the end of 1943 8,000 per month. There were similar, all-but-unbelievable great leaps forward in the production of tanks, ships, landing craft, rifles, and other weapons. And all this took place while the United States put a major effort into the greatest industrial feat to that time, the production of atomic weapons (hardly begun in 1942, completed by mid-1945).

That a cross-Channel attack against the Atlantic Wall could even be contemplated was a tribute to what Dwight Eisenhower called “the fury of an aroused democracy.” What made D-Day possible was the never-ending flow of weapons from American factories, the Ultra and the Double Cross System, victory in the Battle of the Atlantic, control of the air and sea, British inventiveness, the French Resistance, the creation of citizen armies in the Western democracies, the persistence and genius of Andrew Higgins and other inventors and entrepreneurs, the cooperation of business, government, and labor in the United States and the United Kingdom, and more—all summed up in the single word “teamwork.”