By visiting Hiroshima, Obama is casting the powerful presidential spotlight on the haunted memories of one of history's darkest days. He also hopes to remind the world that nuclear weapons remain a global threat when placed in the wrong hands.
Obama arrives in the southern Japanese city late afternoon Friday, with plans to lay a wreath at the saddle-shaped cenotaph in the Peace Memorial Park before delivering short reflections. From a distance, Obama will take in the iconic A-bomb dome, a building skeleton that's come to represent the scale of destruction the bomb imparted.
He's also expected to meet some survivors of the blast, most of whom were young children at the time their city was destroyed and at least 140,000 lives were lost. It wasn't yet clear, however, the extent to which Obama would interact with the Hibakusha survivors, many of whom made loud calls for a presidential audience.
Obama's subdued trip to Hiroshima is expected to last less than three hours.
Reasons not to apologize
Officials say Obama won't apologize for the decision to use an atomic bomb, which many historians insist was necessary to hasten the end of World War II and save lives. Nor will Obama re-litigate the decision to drop a second bomb days later in Nagasaki, where tens of thousands more died.
Such an apology would ripple to the U.S., likely igniting a political firestorm on the home front in the midst of the presidential race. And in countries like China and Korea, where populations were also wiped out during World War II, demands for apologies from wartime foes would only increase.
Even as Obama planned his visit, families of the tens of thousands of Koreans who were killed in Hiroshima and Nagasaki demanded separate recognition from the American president.
Obama said Thursday he hoped to mark Hiroshima as a history-altering moment -- the U.S. is the only country to have ever used a nuclear bomb -- that humanity must avoid repeating.
"The dropping of the atomic bomb, the ushering in of nuclear weapons, was an inflection point in modern history," Obama said during a news conference at the G-7 Summit in Japan.
"It is something that all of us have had to deal with in one way or the other," he added. "Obviously, it's not as prominent in people's thinking as it was during the Cold War, at a time when our parents or grandparents were huddling under desks in frequent drills. But the backdrop of a nuclear event remains something that I think presses on the back of our imaginations."
For Obama, the visit to Hiroshima comes in the last year of a presidency intent on easing longstanding bitterness directed toward the U.S. Visits to Cuba, Vietnam, and Argentina all came with messages of reconciliation and outreach to a younger generation unencumbered with decades-old enmity toward America.
The presidential visit to Hiroshima also takes place after Japan and its Asian neighbors have worked to come to grips with painful wartime brutalities that Japan inflicted upon its enemies, including an apology by Japan for the use of Korean sex slaves during the World War II.
A world without nukes?
Obama further hopes his appearance at the site will serve to reinforce his bid to reduce global stockpiles of nuclear weapons, an effort that's had only moderate strides after seven years in office.
While he successfully negotiated a deal for Iran to curb its nuclear program, North Korea only seems more intent on ramping up its own. And Obama has been accused of hypocrisy for his proposed trillion-dollar overhaul of American's own nuclear weapons program.
Even as Obama prepared for his stop in Hiroshima, long-simmering resentments boiled at the persistent U.S. military presence in Japan. At a joint press conference late Wednesday, Prime Minister Shinzo Abe of Japan railed against an alleged murder committed by an American civilian worker stationed on Okinawa, the southern Japanese island that houses a massive U.S. military presence.
Abe said he "protested sternly" over the incident during talks with Obama ahead of the G-7 Summit, held at a remote luxury hotel overlooking Ago Bay in southeastern Japan.
Japanese resentment, no visit to Pearl Harbor
The bitterness among Japanese over the U.S. bases in Okinawa have persevered for decades, borne from the installation's origin after Japan's defeat in World War II, which led to American responsibility for Japan's defense. Abe was intent this week on demonstrating his fury over the murder, and ensuring that Obama was reminded of the lingering disputes.
Abe's protestations -- unusually blunt for a presidential news conference -- had the effect of making Obama apologize to Japan for the murder, even if that apology wasn't meant as a blanket regret for all of the U.S. military's incursions in the country.
Concerning Hiroshima, Abe said he was looking for Obama to "express the feelings of sorrow" at the Peace Memorial Park, where the President will tour alongside his Japanese counterpart.
But Abe said he had no firm plans to visit Pearl Harbor, in Hawaii, where Japanese planes conducted a surprise morning attack on a U.S. naval installation in 1941.