When President Obama makes his historic Hiroshima visit on May 27, he'll likely see the iconic A-Bomb Dome. It's one of the few structures standing from the Aug. 6, 1945, blast, and the UNESCO World Heritage Site serves as a solemn testament to the devastating power of nuclear weapons.

It's not just the building that's somber: Visitors were mostly silent on the gray morning when I visited Hiroshima during a 2014 reporting trip coordinated by the independent Foreign Press Center of Japan.

Most quietly contemplated the reminders of Hiroshima's horror: At the A-Bomb Dome, the Hiroshima Peace Memorial Park, and at an adjacent museum housing ghostly artifacts such as a display of steps stained with a permanent shadow of an incinerated victim and a watch stopped at the exact moment of the fireball.

But even more impressive than the park, museum or the A-Bomb Dome's exposed iron skeleton was the iron will of Hiroshima's survivors.

Three politely and quietly recalled the randomness of survival, the chaos of the immediate aftermath, and the lifelong struggle to rebuild bodies, lives and society.

But it wasn't the past that most animated them. It was the future.

"If you visit the Peace Park, the peace bell has a map with no borderlines — that's the spirit of mankind," said Sunao Tsuboi, who described his journey from a young man who "got the wrong education" and became a "right-wing person who adored the emperor" to a leading peace activist campaigning for disarmament in several countries. "I found out the lives of human beings are very precious," he said.

Fellow survivor Kenji Kitigawa also focused on a nuclear-free future. "World peace is kind of a dream far away," he said. "It might be difficult, but we have to do something, and the goal is the total ban of nuclear weapons. I feel what I am doing is so small, but one seed of grain will get the crop in the future."

Early in his presidency, Obama shared his dream of a nuclear-free future in a notable Prague speech. But it, too, has been a "dream far away." And the nightmare of nuclear proliferation, terrorism and dangers from existing arsenals will test the next president just as it did his predecessors.

One who hopes to succeed him, Donald Trump, hasn't helped matters by cavalierly suggesting that perhaps Japan and South Korea should develop their own nuclear arsenals, a proposal the White House called "catastrophic" and former Secretary of State James Baker, a Republican, said on Thursday would leave the world "far less stable."

Obama has had some successes. However controversial, the administration's nuclear deal with Iran has so far kept the Persian nation from advancing its potential nuclear weapons program, and no other nation has acquired nuclear weapons during his term. And the 2010 New Start treaty cut the number of strategic warheads maintained by both the U.S. and Russia.

But Kim Jong-Un's unstable behavior has made a nuclear North Korea even more menacing to Asian neighbors and the world. And far from eliminating nuclear weapons, the administration is backing a plan to spend $1 trillion over 30 years to rebuild the U.S. arsenal.

Obama is likely to refocus on his original objectives when he speaks in Hiroshima. What he won't be doing is revisiting history or embarking on what some conservative congressional and media critics have contorted into his latest stop on an "apology tour."

"He will not revisit the decision to use the atomic bomb at the end of World War II," Ben Rhodes, Obama's deputy national security adviser for strategic communication, said in a blog post. "Instead, he will offer a forward-looking vision focused on our shared future."

This vision must be nuclear-free, Kazumi Matsui, Hiroshima mayor and president of Mayors for Peace, told me in 2014. "Hiroshima is a city which has been pulling for the total abolition of nuclear weapons, which are an absolute evil," he said.

On this, he would have few doubters. But many might argue that at least for deterrence they are a necessary evil, especially considering Russia's resurgence, terrorism and proliferation pressures.

But others, like Mayor Matsui, steadfastly disagree. While too young to be a survivor, he showed his own form of fortitude regarding nuclear weapons.

The nuclear age, Matsui said, "is such a short moment in the long history of human beings. When more policymakers can build a world on the foundation of mutual trust, then the world will move toward one without nuclear weapons."

John Rash is a Star Tribune editorial writer and columnist. The Rash Report can be heard at 8:20 a.m. Fridays on WCCO Radio, 830-AM. On Twitter: @rashreport.