Today's Hiroshima does not give television journalists a lot to work with. It is a raucous, bustling, mid-sized Japanese city with only few reminders of its destruction by atomic bomb in 1945.
There is the skeletal dome of the Hiroshima Prefectural Industrial Promotion Hall (which was right under the blast), and discreet plaques on various other buildings saying that such-and-such a middle school, with 600 pupils, used to be on this site, and that is all.
So it is no wonder, with President Barack Obama's scheduled visit (but no apology) to Hiroshima this week that practically every journalist writing about the visit resorts to quoting from Paul Fussell's famous article in the New Republic in August 1981: "Thank God for the Atomic Bomb.''
At a time when all right-thinking intellectuals in the United States deplored the 1945 decision to drop two of America's new atomic bombs on the Japanese cities of Hiroshima and Nagasaki, it was shocking for a university professor to point out that they had saved his life.
For Paul Fussell was a university professor in 1981, but in 1945 he had been a 20-year-old infantry second lieutenant getting ready to invade Japan.
He had already been through almost a year of combat in France and Germany, and he was one of the few original soldiers left in the 45th Infantry Division.
The rest had been killed or wounded, and he had reached the point where he knew he, too, would be killed if his division was committed to combat again. (Soldiers who see real combat all reach this point eventually.)
But his division was going to be committed to combat again. Having survived the war in Europe, he was going to be sent to the Pacific, and the 45th Division would be in the first wave of landings on the main Japanese island of Honshu in March 1946
. Like his few surviving comrades from the European war, he absolutely knew he would die in Japan. And then he heard about the bomb on Hiroshima and the Japanese surrender.
When I interviewed Prof Fussell in the mid-1980s for a documentary, even in recollection the emotions he had felt when he learned that he had been reprieved, that he would live to grow up, were so strong that he was crying and trembling.
The atomic bomb did save his life, and perhaps the lives of a million others who would have died if there had been a full-scale invasion of the Japanese homeland. For him, that was enough.
It will have to be enough for us, too.
In any case, we do not need to engage in the tricky accountancy of balancing the quarter-million horribly real deaths at Hiroshima and Nagasakai against the hypothetical (but quite realistic) estimates of a million military and civilian deaths if the Allies had really had to invade Japan.
There is a different way of looking at the Hiroshima bomb. It is often mentioned by the hibakusha (bomb survivors) who struggle to give meaning to the horrors they experienced.
If not for those bombs on living cities, they argue, the world would not have been afraid enough of these new weapons to avoid a nuclear war all down the long years of the Cold War.
I suspect President Obama sees the logic of that, and he is going to Hiroshima not because it is a symbol of the past, but rather to use it as a warning for the future.
At the beginning of his presidency, in April 2009, he said in a speech in Prague: "As the only nuclear power to have used a nuclear weapon, the United States has a responsibility to act.''
It has not acted decisively yet, and it is unlikely to do so before his presidency ends next January. All he can claim is a deal that probably prevents Iran from becoming the next nuclear power, and a controversial trillion-dollar programme to modernise United States nuclear weapons while reducing the actual numbers.
But if the remaining weapons have more accuracy and higher yields, have you actually achieved anything?
President Obama's heart is certainly in the right place. He has held four nuclear security summits during his presidency, mainly aimed at improving the custody measures meant to keep the weapons out of the wrong hands, and getting the nuclear powers to move away from launch-on-warning postures that keep everybody at hair-trigger alert.
In Hiroshima, he will probably ask the US Senate once more to ratify the Comprehensive Test Ban Treaty (10 years and counting). He will talk up a proposed new treaty banning the production of fissile material.
He may even call for a world without nuclear weapons, although that is a concept that does not have much support in Washington.
But it is hard to get the world's attention when the threat of nuclear war seems low, and almost impossible to get real concessions out of the great powers when it seems high.
In the end, President Obama is just using Hiroshima to remind everybody that we have a lot of unfinished business to conclude in the nuclear domain.
-Gwynne Dyer is an independent London journalist.
