During the Cold War, the United States supported selective nuclear proliferation as a means of deterring a Soviet invasion of Europe. The Russians might not believe that the United States would trade Berlin for New York, but they might find a British or French threat more credible.
Washington did not pursue the same strategy in Asia. Although Japan could easily match Britain or France in economic power and technological sophistication, the United States didn’t see fit to support Japanese nuclearization. Instead, the United States quashed Japanese nuclear ambitions whenever they appeared.
This decision was well considered, given the effect that Japanese nukes might have had on the course of global nuclear proliferation. But had the balance of power in East Asia shifted in a different direction, arming Japan with nukes might have made more sense. Such a development would have had huge implications for the spread of nuclear weapons across the world.
The legacy of World War II
Japan briefly pursued atomic weapons during World War II, although its efforts came nowhere near matching those of Germany, much less the United States. However, the United States destroyed the project’s infrastructure early in the occupation, making clear that Japan would not soon rejoin the community of nations, at least in terms of self-defense.
The precedent of Pearl Harbor rested heavily on American minds, and the idea that Japan might acquire weapons that would enable it to undertake a far more devastating sneak attack was deeply unpopular. While the United States supported British and tolerated French nuclear efforts, Japan was different. Britain and France were part of the victorious Allied coalition in World War II, while Japan was a defeated aggressor state.
As the only victim of a nuclear attack, Japan’s domestic politics made a nuclear turn difficult. However, during the 1960s, the Japanese government actively considered the development of a nuclear weapons program.
Japanese Prime Minister Eisaku Sato argued that Japan needed nuclear weapons to match those of China; however, the United States demurred. Instead, the Johnson administration pressed for Japanese accession to the Nuclear Non-Proliferation Treaty, ending, for then, Japan’s nuclear ambitions.
Read the Remainder at War is Boring