The Key That Unlocked World War II

Enigma machine at Bletchley Park Museum in 2006. (Alessia Pierdomenico/Reuters)
War of Shadows: Codebreakers, Spies, and the Secret Struggle to Drive the Nazis from the Middle East, by Gershom Gorenberg (Public Affairs, 474 pp., $34)

Russia, Winston Churchill famously said on the eve of World War II, “is a riddle wrapped in a mystery inside an enigma; but perhaps there is a key.”

In an illuminating, thoroughly researched new book, Israeli journalist and historian Gershom Gorenberg provides a different kind of key to another mystery involving a different sort of Enigma, namely the Nazi system of codes that proved critical to their failure in the Middle East and their ultimate defeat.

In War of Shadows, Gorenberg unlocks a central mystery that befuddled military historians for decades: How was the famed Nazi field marshal Erwin Rommel able to steamroll British and Allied forces in North Africa for more than a year, reaching the brink of conquering Egypt and cracking the British Empire nearly in half, only to suffer an ignominious and consequential humiliation at El Alamein in July 1942 that began to turn the tide of the war?

Gorenberg describes his own book as “a distinctly new portrait of one of the great turning points of the last century.” Indeed, he has marshaled an impressive array of diplomatic cables archived at various British, Israeli, German, Italian, and American facilities, as well as the personal papers of numerous key figures in the story.

Enigma was, at least in theory, an immensely complex system, comprising nearly 2 billion possible settings in its original design. It relied on three toothed wheels containing a nest of wiring that connected a keyboard to a lamp board and enabled encryption. Each keystroke moved the first wheel a single notch, and, after 26 entries, the second wheel ticked one slot. Only after the second wheel completed its full rotation would the third wheel move as well, meaning it took more than 17,000 (26 to the power of three) keystrokes for the wheels to return to their original setting.

The sending party would note the initial setting of the three wheels prior to transmission and convey that setting to the receiving party as a sort of preamble to the message itself. But to enhance security further, the transmitting agent would use Enigma to encode that starting position.

Fortunately for the allies, a brilliant Polish cryptographer named Marian Rejewski had used complex mathematics to crack the secrets of Enigma’s wiring years before the Nazis marched on Warsaw. Allied forces spirited him and his team across the Continent, and ultimately to Bletchley Park.

Yet even without this crafty reverse-engineering, British cipher hacks had managed to decrypt German messages mainly because, as Gorenberg puts it, while “Enigma appeared unconquerable,” in fact “its fundamental flaw was that human beings built it, and other human beings could see it differently. . . . Any lock that one human mind can design, some other human mind will eventually see a way to break.” In particular, Bletchley’s Gordon Welchman and Alan Turing figured out that German encoders would frequently reuse preamble codes, especially in messages broken up into parts, or forget to reset the wheels in subsequent transmissions.

These signals-intelligence exploits coincided with military developments in a crucial theater. The Middle East, and Egypt and Palestine in particular, proved indispensable to the British war effort, as they represented the very hinge of the empire, connecting the Mediterranean to the oilfields of Persia and Iraq through the Suez Canal and the Arabian Peninsula. Maintaining a hold on Egypt and other parts of North Africa afforded Britain “a chance to threaten Italy and Germany from the south,” and accordingly Churchill reinforced regiments there even in the eye of the Battle of Britain.

For the Jews of Mandatory Palestine, the Nazis’ designs on the Middle East proved equally fraught. Hitler intended to accompany Rommel’s conquest of the Holy Land with an Einsatzkommando unit escort — the “SS special operations command for mass murder.” The Nazis and Italians made common cause with the Mufti of Jerusalem, Haj-Amin al-Husseini, who exhibited particular excitement at the prospect of throwing Palestine’s Jews into the sea (but whose genocidal efforts Gorenberg seems strangely determined to downplay).

At the same time, Italy coveted Egypt for reasons similar to Britain’s, seeking to unite its own colony in Libya with its newly conquered territory in Ethiopia. Yet Mussolini’s forces were badly outclassed in desert battle after desert battle in 1941, with Ralph Bagnold, the founder of Britain’s Long Range Desert Group, repeatedly outfoxing his counterparts among the dunes and oases; at one point, over 100,000 Italian troops fell prisoner. According to a contemporaneous American report, “the British daringly stretched the mobility of their armored units to the limit” and “the Italians avoided the desert . . . while [the British] found security in the desert and lived therein.” Soon thereafter, the British retook Tobruk, a key northeastern Libyan harbor, and advanced all the way to Benghazi in the north while invading Ethiopia in the South.

But by the spring of 1941, Rommel turned his eyes southward and dislodged the British from Libya’s Cyrenaican peninsula, pushing them back to the Egyptian border. The two sides traded blows for a year, with the front undulating east and west across the desert. A critical moment arrived in mid 1942, with the Nazis bearing down on Egyptian lines in eastern Libya and the Panzer Army gathering momentum.

In parallel, British intelligence decrypting Enigma cables had recently begun noticing frequent references to a “good source,” whom Margaret Storey, an expert signals counterintelligence officer at Bletchley Park, labeled “Bluebird.” Apparently, someone in Cairo was providing the Nazis with surprisingly accurate military information seeming to originate in British offices. Eventually, British cryptographers ingeniously determined that the leak sprang from cables passed between British military intelligence in Cairo and Bonner Frank Fellers, the American military attaché on the ground there. Evidently, the Italians, with the assistance of codebooks purloined from the U.S. Embassy in Rome, had cracked weak American ciphers. By the time the Allies had figured it out, British Special Air Service commandos dressed as Germans (including several specially trained Palestinian Jews) were en route to attack German airfields in Martuba and Derna, an assault that mostly foundered, as the tipped-off Nazis had fortified their defenses.

Shortly thereafter, Tobruk fell to the Axis, the British Eighth Army withdrew to El Alamein in Egypt, only 60 kilometers from the critical port of Alexandria, and Hitler lasciviously eyed “the collapse of the entire eastern part of the British empire.” It took a disturbingly long time for the Americans to plug the leak, and Rommel exploited the opportunity to advance nearly to the doorstep of Cairo, where nervous British officials began in June 1942 to burn documents and to ready evacuation plans.

Yet plug it the Americans did, and not a moment too soon: One of the final leaked cables suggested the Eighth Army would make its final stand at the coastal redoubt of Mersa Matruh, but immediately thereafter, the British decided to fall back to El Alamein instead, some 180 kilometers further west. So when Rommel arrived at a deserted Mersa Matruh, he assumed the Nile Delta was his for the taking, streaking his forces across thinned supply lines toward Alexandria.

Meanwhile, Bletchley Park had fully cracked the Desert Fox’s communications, feeding them securely to El Alamein, where the Brits lay in wait. As Rommel approached, South African and Indian artillery divisions rained down projectiles, stalling the Nazi advance. The Panzer Army couldn’t advance because of the Allied counterattack, and it couldn’t retreat because of Hitler’s directives, so it languished in the desert for months until it was finally dislodged by the newly installed General Bernard Montgomery’s forces. This victory, in Churchill’s unforgettable phrasing, signified “not even the beginning of the end” but “the end of the beginning.”

Thus, in a tightly contested battle, it seemed that Britain’s intelligence edge furnished the margin of victory. As Gorenberg memorably puts it, throughout May and June, Rommel “had two good eyes,” but, just as he burst into Egypt, he “lost one eye, the stronger one,” at the exact moment that “with each new success at reading Enigma keys, the cataracts were removed from the eyes of the British.” As the war wore on, the Allies’ vision continued to sharpen while the Nazis’ sight, like their prospects, grew ever blurrier.

War of Shadows is not without its problems. Most prominently, Gorenberg tries to do too much, attempting to cover far more ground than reasonably possible in a book of this length. His dizzying array of important figures (nearly 150 listed in the “cast of characters”) and theaters of operation (no fewer than ten), coupled to his jump cuts between and among them, lend War of Shadows an air of disorganization that, while perhaps appropriate to the chaotic nature of the war years, does the reader no favors.

For example, Gorenberg lavishes dozens of pages upon the exploits of Johann Eppler (a.k.a. Hussein Ghafar) and Heinrich Gerd Sandstede (a.k.a. Sandy), German Abwehr agents who had burrowed deep into British circles in Cairo with the assistance of the Hungarian Nazi collaborationist Laszlo Almasy. Yet none of these characters played any significant role in the plot, serving instead as red herrings.

In addition, there are better, more focused books on the subjects of Enigma and El Alamein; Gorenberg is an expert neither in cryptography nor military strategy and occasionally appears out of his depth.

But the great virtue of War of Shadows lies in how it stitches disparate threads together into a single tapestry depicting a critical moment of the war when seemingly everything hung in the balance. Best of all, Gorenberg recounts the climactic moment in gripping, cinematic fashion, nicely capturing the emotional tenor of the key figures. He formulates a clever, unified theory of how human ingenuity both makes and unmakes historical figures and sets the course of the future.


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