Continued from page 2

Still, Mr. Obama remains a popular figure in Japan — Obama T-shirts are on sale at the Peace Park’s museum — and many would welcome a visit.

Katsuko Nishibe, a 61-year-old peace activist, said she welcomed the decision to send Mr. Roos, but added that she thought it was dangerous to think that the bombing of Hiroshima was justified.

“We have a very different interpretation of history. But we can disagree about history and still agree that peace is what is important. That is the real lesson of Hiroshima.”