|Their tiny tanks never stood a chance.|
His purpose is, by wild coincidence, to tell the world how awful nuclear proliferation is (except, say, in Iran) but he reportedly has no plans to specifically apologize for the bombs which ended World War II with impressive finality.
Still, his visit is seen internationally as an acknowledgement that America once did a very, very mean thing and, now that many young Americans have no freaking sense whatsoever of history, we feel just awful about it. Come here, Hiroshima - you need a hug!
By the way, as long as we've mentioned people being increasingly clueless about history, the link above goes to a story in US News & World Report which reports that we dropped a hydrogen bomb on Hiroshima on August 6th, 1945. Which was a pretty good trick, considering that the first hydrogen bomb (1000 times more powerful than the Hiroshima bomb) was test-detonated seven years later in 1952.
But hey, why let little things like empirical facts and actual history spoil a story about what assholes we were back in the 1940's? And for that matter, why should those realities deter Barack Obama from his latest strident stop on the seemingly unending "blame America first" tour?
After all, he's not going to become Secretary General of the UN without campaigning for it.