History Debate: Japan's Surrender in WWII

This post actually isn't about Truman and the Bomb.  Take a look at a relatively new take on Japan's surrender:

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.

I'd have to look into Hasegawa's research before I can form an educated opinion. Oh, and as for  the news writer's bit about "provocative questions about nuclear deterrence, a foundation stone of military strategy in the postwar period," I will take issue with that.  You can't possibly be saying that the idea of mutually assured destruction didn't play a big role in how the US and USSR as Cold War superpowers regarded each other.