Opinion: Codebreaking history prompts Pearl Harbor reflections, 80 years after the surprise attack
If the United States had known that Pearl Harbor would be bombed on the morning of Dec. 7, 1941, "Battleship Row" would have been empty, the ships all moved into the open sea, with air support, prepared to defend themselves. The Japanese bombers could have lost their way, temporarily; they were homing in on the transmission beam of a local radio station, which could have been moved out to sea. American fighter planes could have been aloft and waiting. It's possible the war's opening salvo would have become a major defeat for Japan.
Move history back another year-plus — to Nov. 14, 1940. Hitler's blitz of England was well underway, with Nazis dropping tons of death on British targets, commonly London or military bases. But the Nov. 14 target was peaceful Coventry, whose residents had no idea the enemy was coming. They could have left town. Britain's airmen could have intervened.
And it's possible that British intelligence — and Prime Minister Winston Churchill — did know. But said nothing.
In what was likely the best-kept secret of the war, British codebreakers had by then solved the Nazi code. British leaders had advance notice of every major Nazi move — a huge plus for the outnumbered and out-equipped nation. Losing that advantage could mean losing the war in Europe. And alerting Coventry prior to the attack would surely alert the Germans that their code had been broken.
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When the possibility was raised, many close to the issue were indignant that such a thing could be suggested. But others were not so certain.
Years later, Capt. Frederick Winterbotham of the British Secret Service wrote that withholding the information from Coventry was costly, but that revealing the secret that the code was broken would have been catastrophic.
"This was the sort of terrible decision that sometimes has to be made on the highest levels in war. It was unquestionably the right one," he wrote.
And as a result, on that Nov. 14 night, Coventry burned, 558 Britons were killed, thousands were injured. How many lives in how many nations were saved by maintaining the secrecy is, of course, beyond calculation.
Many years after World War II ended, Winterbotham revealed the truth of Coventry and the secret of Bletchley Park, the estate north of London where a dedicated — and truly heroic — team of men and women studied, and broke, enemy codes. He drew a storm of criticism from those who felt the secret should stay hidden forever.
What about Japanese codes?
Eighty years have now passed since the Japanese bombing of Pearl Harbor that sent the United States into the war. But a question has survived decades of speculation: Is it possible that Churchill knew that the Japanese attack was coming? And he chose to keep the secret?
The answer from most is a firm and final "no." Nevertheless, the bombing of Coventry "was not the only instance in which Churchill and Bletchley Park were suspected of having connived to withhold information," says Sinclair McKay in his 2010 book "The Secret Life of Bletchley Park." Years after the Dec. 7, 1941, surprise attack by Japan on the U.S. fleet at Pearl Harbor, "it was suggested by some sources that Bletchley Park … had decrypted vital messages concerning Japanese military intentions. The allegation was that having seen such intelligence, Churchill ordered it to be suppressed so that the Americans would gain no advance warning, thus insuring that the attack would bring the USA into the conflict."
"Surprise" was not a necessary element of American reaction to Pearl Harbor; the attack, however successful or unsuccessful it would have been without its secrecy, would have outraged our nation. As it was, on the following Monday morning, American men were lined up outside of recruiting offices all across the nation.
But Pearl Harbor came at a time when much of America was isolationist, and firmly opposed to our joining the battle against Hitler, although our Lend-Lease program was supplying Russia with megatons of weapons. (Prior to Pearl Harbor, a letter to the editor of the Des Moines Register scolded that the paper's stand on the issue was forcing others to fight "our war." It drew an editor's note: "Why is it 'our war'?")
10 minutes that changed the war at Midway
Codebreaking was a factor in the 10 minutes that turned the war around in June of 1942. Our forces did not know where the Japanese fleet was headed that summer, but assumed it was Midway Island. If they could capture Midway, they would be close enough to Hawaii that their bombers would not need aircraft carriers to supply them with fuel. Our navy, although seriously diminished by the loss of ships at Pearl Harbor, intended to intercept. The codebreakers had solved the Japanese code, but the Japanese were using a phony name rather than "Midway" in reference to its objective. Its true target could have been another island.
Our navy sent a fake message from Midway claiming that the water system was broken. The Japanese sent that info to its high command, using its code name for Midway. That ended speculation.
A series of coincidences led to the 10-minute turnaround of the war in the Pacific. Our dive bombers got a late start. They were preceded by a flight of torpedo planes; every single torpedo missed, and every single torpedo plane was shot down. But they had brought the Japanese fighter planes down from the high skies, leaving those skies open for the few minutes our dive bombers needed. They sank three aircraft carriers and critically damaged a fourth. And destroyed the Japanese offensive effort.
Dwight Eisenhower said the codebreakers at Bletchley Park shortened the war by at least two years. McKay's fascinating book finally acknowledges their contribution.
Bill Leonard is a retired Des Moines Register editorial writer.
This article originally appeared on Des Moines Register: Opinion: Pearl Harbor 80th anniversary and reflections on codebreaking
