Barack Obama will on Friday becomes the first U.S. president to visit Hiroshima, site of the world's first atomic bombing, a gesture Washington and Tokyo hope will showcase their alliance and breathe life into stalled efforts to abolish nuclear arms.
Even before it occurs, though, the visit has stirred debate, with critics accusing both sides of having selective memories, and pointing to paradoxes in policies relying on nuclear deterrence while calling for an end to atomic arms.
The two governments hope Obama's tour of Hiroshima, where an atomic bomb dropped on Aug. 6, 1945, killed thousands instantly and some 140,000 by the year's end, will highlight a new level of reconciliation and tighter ties between the former enemies.
Aides say Obama's main objective in Hiroshima, where he will lay a wreath at a peace memorial, is to showcase his nuclear disarmament agenda. He won the Nobel Peace Prize in 2009 for what many said were eloquent speeches on the topic.
Obama has said he will honor all who died in World War Two but will not apologize for the bombing of Hiroshima. The city of Nagasaki was hit by a second nuclear bomb on Aug. 9, 1945, and Japan surrendered six days later.
A majority of Americans see the bombings as having been necessary to end the war and save lives, although many historians question that view. Most Japanese believe they were unjustified.
"Our visit to Hiroshima will honor all those who were lost in World War Two and reaffirm our shared vision of a world without nuclear weapons, as well as highlight the extraordinary alliance that we have been able to forge over these many decades," Obama told a news conference after arriving in Japan for a Group of Seven summit.
The White House debated whether the time was right for Obama to break a decades-old taboo on presidential visits to Hiroshima, especially in an election year.
But Obama's aides defused most negative reaction from military veterans groups by insisting he would not revisit the decision to drop the bombs.
World War Two flying ace Dean "Diz" Laird, 95, who shot down Japanese fighters and dropped bombs on Tokyo, said he was pleased both that Obama was going to Hiroshima and that he would offer no apology.
"It's bad that so many people got killed in Hiroshima, but it was a necessity to end the war sooner," said Laird, the only known U.S. Navy pilot to shoot down both German and Japanese planes during the war.
"I believe in at least showing the Japanese that we care because they are now our good allies."
Laird, who lives in California, suggested the time was past when Japan had to keep atoning for its wartime history: "There were a lot of atrocities but that war is over."
Critics argue that by not apologizing, Obama will allow Japan to stick to the narrative that paints it as a victim.
Abe's government has affirmed past official apologies over the war but said future generations should not be burdened by the sins of their forebears.
Atomic bomb survivors, have said an apology from Obama would be welcome but their priority is ridding the world of nuclear arms, a goal that seems as elusive as ever. Some also worried insistence on an apology would keep Obama from visiting at all.
"If the president is coming to see what really happened here, and if that constitutes a step towards the abolition of nuclear arms in future, I don't think we should demand an apology," Takeshi Masuda, a 91-year-old former teacher whose mother died a few weeks after being caught in the bombing, told Reuters last month.
Anti-nuclear activists hope Obama's visit will breath life into a stalled process while critics argue the president has made scant progress and is spending heavily to modernize the U.S. atomic arsenal. Japan, despite advocating disarmament, relies on the U.S. nuclear umbrella for extended deterrence.
In the end, Obama's gesture may be a sort of Rorschach test, a psychological inkblot in which viewers see what they are predisposed to perceive.
"Politics being what it is, the president's visit will be used by activists of every ideological stripe," said Massachusetts Institute of Technology political science professor Richard Samuels.