When Barack Obama visits Hiroshima tomorrow he will be the first serving US president to do so. It is a welcome development full of symbolism. However, it is as much about burnishing the president's legacy as an international statesman as the ostensible emphasis on the warmth of the political and strategic relationship between the US and Japan.
It will not involve an apology for the atomic bomb dropped on August 6th 1945 that took 140,000 lives and which, with Nagasaki three days later, brought the second World War to an end. The US president is expected only to acknowledge "the tremendous human cost of war".
Hiroshima’s survivor and peace groups say their priority is a strong reaffirmation of Obama’s 2009 aspiration of a “world without nuclear weapons”.
Although a diminishing majority of Japanese still believe that the use of the nuclear bomb was unjustified, most do not believe the US needs to apologise. On the nationalist right, however, the lack of an apology feeds the sense of Japanese victimhood.
Obama won the Nobel Peace Prize in 2009 partly for his stance on nuclear non-proliferation but his record has disappointed. The US has yet to ratify the Comprehensive Nuclear-Test-Ban Treaty despite his promises.
There was also a new nuclear arms reduction deal with Russia in his first term in which they agreed to reduce their nuclear warheads to 1,550 each by February 2018 – both, to date, have maintained more than 7,000 apiece.
But last year's nuclear pact with Iran was an important step forward and Obama has to date convened the Nuclear Security Summit four times. On balance, nuclear and non-nuclear powers remain, if anything, further apart – the treaty obligations on the former gradually to disarm, a pious aspiration .