On Tuesday, President Obama announced his decision to visit Hiroshima, Japan, the site where the U.S. dropped an atomic bomb in August 1945. Obama will specifically visit Memorial Park, which commemorates the event; he will be the first sitting American president to do so, although he does not plan to offer any sort of apology. The bombing of Hiroshima killed around 100,000 people; three days later, tens of thousands more were killed after the United States bombed Nagasaki.

To discuss the issues of war and memory, I spoke by phone with Carol Gluck, a professor of Japanese history at Columbia University. We talked about the ways in which the American and Japanese narratives of the war have changed over time, how nationalism has shaped the memory of World War II, and why Obama’s decision to visit is symbolically important. The conversation has been edited and condensed.

Isaac Chotiner: What did you make of President Obama’s decision to visit Memorial Park?

Carol Gluck: I think it is a very good decision. I think it is a decision that probably would have made sense to do earlier, but it makes particular sense to do in the context of President Obama’s anti-nuclear policies. It also makes sense in terms of the alliance between Japan and the United States. I think the question is why it took 71 years for this to happen. And I think there are answers to that.

Which are?

The first reason is that the atomic bomb narrative is extremely strong in every country I have studied. It is one of the few aspects or parts of the story of the Second World War that haven’t changed, while other parts have. The countries’ national nuclear narratives are very much locked in place. The Japanese national narrative is that the bomb gave Japan a mission for peace in the world. The bomb doesn’t end the war: It starts the postwar mission for peace. The American narrative is that the bomb ended the war and saved American lives. That’s the story.

The second reason is that the politics of apology have gained more emphasis since the end of the Cold War. ...