Codebreakers Victory (25 page)

 

 

The Afrika Korps: Ultra Tightens the Noose

 

In 1942, after the U.S. had joined the war, Anglo-American planners held long discussions on how to conduct joint future campaigns. The Americans argued for a cross-Channel invasion in 1943. Knowing how much preparation was needed before that attempt could be made, the British advocated that the first substantial combined operation should instead be a series of North African landings. Agreement was reached and a timetable set for the autumn of 1942, with a little-known American general, Dwight D. Eisenhower, in charge.

It was just as well that the British won the argument. The North African landings showed up countless fumbles, mix-ups and snafus that needed to be corrected before taking on the Germans in northern France.

The North African expedition was, in fact, a tissue of bungles. The primary objective was to seize the Tunisian ports of Bizerte and Tunis, to prevent the Axis from using these ports that provided the nearest and best harbors for transports from Sicily and Italy and the best exits for an evacuation. To achieve the objective, the British felt sure, the landing should be made as far east as possible, hard on the Algeria-Tunisia border. The Americans were cautious about venturing so far. All sorts of fears entered in—among them the threat that Hitler might press France and Spain into allowing German passage through to capture Gibraltar, whose fall could maroon troops east of the Rock. To forestall any such eventuality, the Americans urged at least one landing in Morocco, west of Gibraltar. With that safeguard, a Mediterranean landing could also be contemplated.

A compromise was reached. Operation Torch would be made up of three landings: at Casablanca in Morocco, and at Oran and Algiers in Algeria. After securing these sites, it was thought, Allied troops could speed across land to capture the Tunisian ports.

The trouble was that even the easternmost landing, in Algiers, was still 450 miles from Tunis. They were tough miles, much of the way through rugged mountain terrain. As canny Scots general Kenneth Anderson noted, the race for Tunis was lost before it began.

The November 8, 1942, landings came just four days after Rommel's defeat at El Alamein. In themselves they represented a magnificent achievement. An armada of some five hundred American and British ships had set out from ports as far apart as Portland, Maine, and Lock Ewe, Scotland, and had converged on North Africa without ever being touched by German U-boats. GC&CS decrypts showed that Axis leaders knew something big was afoot, but the messages also disclosed uncertainty about the destination. Italy, Sardinia, Sicily, Malta, the Aegean? The Axis commanders' most favored answer, as Ultra made clear, was that this was a convoy bound for the relief of Malta. The Allies used that information to carry off a bit of deception. The Mediterranean ships made a feint as though heading for Malta, then wheeled about and sailed for Algiers. The Axis commanders were fooled, and the landings were a surprise.

Aside from the Allies' own foul-ups, the landings went off more smoothly than anticipated. Only at Algiers did the French troops, supposedly loyal to the Vichy regime, show troublesome resistance. The Axis Mediterranean submarines managed only two attacks and damaged one ship. The German and Italian air forces were caught unprepared and did little to harass the landings. Neither France nor Spain acceded to a German march on Gibraltar.

One big problem remained: Tunis and Bizerte were objectives too far. Algerian roads were in poor condition. Railroad equipment was ancient and the tracks were of mixed gauges. The intended harelike dash was slowed to a tortoise crawl.

In addition, the planners seriously misjudged the Axis response. With Rommel beaten and the Russian offensive demanding close attention, the Allies doubted that Hitler would try another major gamble in North Africa. Even if he did, they believed, the preparations would take weeks. They were wrong on both counts. Hitler saw the danger in allowing the enemy to gain possession of the ports providing the best jumping-off point for an invasion of Sicily and Italy. The troops, armor and planes that Rommel had pleaded for and been denied now flowed in great numbers and with stunning speed into Tunisia. The capable, aggressive General Jürgen von Arnim was called back from the Russian front to share command with Rommel.

The Allies' push to reach the ports foundered. In addition to the surprising resistance by the Germans, winter rains turned roads into quagmires. Eisenhower called off the offensive, and both sides settled down to a winter spent gathering their strength. The race for Tunis had, indeed, been lost.

By the time the Allies resumed their drive into Tunisia, their intelligence advantage had become even more overwhelming. With mastery of Luftwaffe traffic a routine matter, BP cryptanalysts were also penetrating Wehrmacht Enigma ciphers. They had broken a new Enigma key that provided a fresh font of knowledge about Axis shipping. Italy's air force book code and Hagelin-encoded navy cipher were being quickly read. And Magic decrypts of Baron Oshima's reports continued to be helpful.

Axis commanders, by contrast, were reduced to guesses and hunches. An example of what this disadvantage could mean in battle came when Rommel—with his Afrika Korps troops safely dug in at the Mareth Line of old French fortifications in Tripoli—hurried west to join Arnim in organizing attacks against the Allies trying to hold the passes in the Atlas Mountains. Rommel's panzers succeeded in overpowering the untried American troops in the Kasserine Pass and fanned out into the plain beyond. He could have placed the whole North African operation in jeopardy if he had kept his drive going. But he had to guess at what lay ahead, and his guess was that the Allies were readying a counterattack that could trap him. Although his guess was wrong, he had no means of dispelling the uncharacteristic sense of caution that overcame him. When an American artillery division was hastily brought forward and began lobbing mortar shells onto Rommel's armor, he called off the offensive and withdrew through the pass. What was perhaps the greatest Axis opportunity in the campaign withdrew with him.

The battle for Tunisia was a series of gory thrusts and counterthrusts that continued through March and April and into May 1943. The code-breakers influenced the outcome in two critical ways. One was by keeping the Allied commanders informed about virtually every major action their Axis counterparts planned to take. The other was by directing the stranglehold on Axis supply lines.

Ultra's effects on strategic operations are exemplified by a March 3 decrypt that Hinsley described as of "decisive importance." It alerted Montgomery that Rommel, back with his old Afrika Korps troops, was organizing a surprise breakout from the Mareth Line against the Eighth Army on March 6. In a hard-driven day-and-night frenzy of activity, Monty used the three days to quadruple the forces in place at the point Rommel meant to strike. An in-depth massing of 470 antitank guns and 400 tanks was camouflaged to blast the Germans as they came forward. Rommel wrote later, "It became obvious that the British were prepared for us." After his attack had failed, the Desert Fox went home to Germany. This time he did not return.

Once more the Germans suspected that Enigma had been compromised. The British high command rebuked Montgomery for not making a greater effort to disguise the source of his intelligence. But again the suspicions were quelled, and use of the Enigma never wavered.

U.S. general Omar Bradley told, in his
A General's Life,
how the code-breakers helped the American soldiery regain a measure of respect from their British allies after the near rout of the GIs at Kasserine Pass. Arnim planned, on March 23, a counterattack against the U.S. II Corps at El Guettar. "Our front-line codebreakers," Bradley wrote, "picked up and decoded the order, giving us a full day's notice. . . . A second decoded message provided us further valuable details on the attack." So warned, the Americans "mauled the Germans and Italians . . . it was the first solid, indisputable defeat we inflicted on the German Army in the war. Kasserine Pass had now been avenged."

As for the Axis supply situation, Ultra decrypts made the clampdown by the Allies all but total. Arnim's armored divisions, like those of Rommel before him, were immobilized by lack of fuel. Many of his soldiers were soon existing on two slices of bread per man per day.

Without transports and control of the sea, Axis commanders could not manage a Dunkirk. When resistance ended and Arnim surrendered on May 13, Hitler and Mussolini had no choice but to abandon 275,000 German and Italian soldiers and all their equipment.

From Tunis, Alexander sent a message to Churchill: "Sir, it is my duty to report that the Tunisian campaign is over. All enemy resistance has ceased. We are masters of-the North African shore."

So ended an error-filled campaign that had resulted in more than one hundred thousand men—Germans, Italians, Britons, Americans, French—being killed, wounded or missing in action. As Rommel colorfully phrased it, "Rivers of blood were poured out over miserable strips of land which, in normal times, not even the poorest Arab would have bothered his head about."

But the campaign opened the underbelly of Europe to Allied attack, and it welded the Allied forces into a strong, unified and confident team. From the perspective of the codebreakers, the greatest significance was that the campaign proved to Allied generals the value of trusting their intelligence sources.

 

 

 

10

 

Turnaround in the Pacific War

 

 

For the six months following Pearl Harbor, the Japanese war machine was invincible. The U.S. islands of Guam and Wake fell within days after the Pearl Harbor raid. In the Philippines the Japanese sliced up the American and Filipino armies, forcing the Americans to retreat into the hopeless corners of Bataan and Corregidor and, in May 1942, to surrender. On the China coast, the American garrisons at Shanghai and Tianjin were seized. British-led forces were pushed out of Burma and Malaya. The Dutch East Indies yielded up their riches not only in oil but also in rubber, rice, timber and metals. The strategic stronghold at Rabaul in New Britain fell. The Japanese extended their Greater East Asia Coprosperity Sphere to include the whole arc of the central, south and southwest Pacific and were threatening the supply lines between the U.S. and Australia.

During those first months of 1942, the leadership that would direct the U.S. war effort in the Pacific had established itself. In Hawaii, Admiral Chester W. Nimitz had become the new commander of the Pacific Fleet. General MacArthur had been ordered to leave his besieged troops on Corregidor and escape to Australia in a torpedo boat. Moreover, the two commanders' cryptologic support teams were firmly in place. On Oahu, Edwin Layton, the fleet's chief intelligence officer, and Joe Rochefort were relieved to find that Nimitz refused to consider any shortcomings in their Pearl Harbor performance and wanted them to continue serving him. MacArthur had seen to it that his Cast cryptographers were spirited away to Australia on submarines before he himself left the Philippines, vowing, "I shall return."

In terms of cryptology, the explosive geographic expansion by the Japanese had one consequence that was to bring a decisive reversal in the course of the war. Japanese intelligence leaders knew that the security of their systems depended on regular replacement of the codebooks that were the basis of their nonmachine codes. They had planned to change their workaday naval code, JN-25, on April 1, 1942, but the distribution of their codebooks was made impossible by the twenty-million-square-mile spread of Japanese commands and the growing profusion of recipients. The date for the changeover was pushed back to May 1, then to the beginning of June. The delays gave Allied cryptanalysts those extra months to master JN-25.

In the windowless basement of the Fourteenth Naval District's Administration Building, known as "the dungeon," Joe Rochefort was on hand virtually nonstop. He paced around with a red smoking jacket over his uniform, both to keep him warm in the dank quarters and to provide the deep pockets he needed for his pipe, tobacco pouch and copies of messages of special interest. His work uniform was completed with house slippers because the concrete floors hurt his feet. In addition to overseeing the direction-finding, intercept, and traffic analysis operations along with cryptanalysis, Rochefort had to manage the influx and training of new recruits now flooding into his cellar headquarters.

Of these newcomers the most bizarre was a contingent of musicians left jobless by the severe damage to their ship, the USS
California,
in the Japanese attack. To the amazement of Rochefort and Dyer, the band provided capable and even some exceptional additions to the team.

The new, closer cooperation between the Allied cryptographic units in the Pacific and in Washington quickly began to produce results. Gone were the cumbrous communications methods of the pre-Pearl Harbor days. Now the cryptanalytic units flashed new discoveries to each other via radio-teletypewriter links. Soon the analysts were solving some forty percent of JN-25's code groups, but since those were the most often used words and phrases, the meaning of a high percentage of entire messages could be determined, or at least guessed at.

In April the U.S. military, knowing how badly the American people needed a morale boost, planned what became known as "Doolittle's raid" on mainland Japan. Colonel James Doolittle would load sixteen B-25 bombers on the flight deck of the aircraft carrier USS
Hornet,
slip within five hundred miles of Japan, lead the bombers so they could drop bombs and incendiaries on Tokyo and other cities, and fly on to those parts of China still held by Chiang Kai-shek. To carry out this bold act, the
Hornet
was joined by Admiral William F. "Bull" Halsey on the aircraft carrier
Enterprise
and by several escort vessels. Fortunately, Halsey's crew included an experienced intelligence officer and intercept operators. When the task force was still well short of its five-hundred-mile goal, the intelligence team picked up Japanese radio traffic revealing that Halsey's ships had been sighted. Japanese leaders took almost two hours to overcome their shock and disbelief, but then their radio channels crackled with transmissions as they sought to organize a huge sea hunt. Halsey decided to launch the bombers sooner than planned but not so late that his precious carriers and other ships would be endangered. While the attacks themselves were mere pinpricks, the raid gave the U.S. the semblance of a reprisal for Pearl Harbor, a publicity bonanza and a lift to American spirits. FDR stirred imaginations by claiming the bombers were launched from Shangri-La, the mythical kingdom in James Hilton's novel
Lost Horizon.