Codebreaking did not erase the larger Pacific War imbalance

Did American codebreaking make Japan's defeat inevitable?

Codebreaking mattered, but Japan also broke some codes; American scale still made victory unlikely, although a longer war might have changed the terms of defeat.

American codebreaking alone did not make every later outcome inevitable. Japan also broke some enemy codes, so signals intelligence was not a one-sided ability. The scale of the United States nevertheless remained the decisive obstacle to a Japanese victory. A longer and harder war might have produced a less severe defeat, but the answer does not make outright Japanese victory likely.