In recent years, however, a new interpretation of events has emerged. Tsuyoshi Hasegawa - a highly respected historian at the University of California, Santa Barbara - has marshaled compelling evidence that it was the Soviet entry into the Pacific conflict, not Hiroshima and Nagasaki, that forced Japan's surrender. His interpretation could force a new accounting of the moral meaning of the atomic attack. It also raises provocative questions about nuclear deterrence, a foundation stone of military strategy in the postwar period. And it suggests that we could be headed towards an utterly different understanding of how, and why, the Second World War came to its conclusion.