[TOKYO] President Barack Obama will visit Hiroshima, Japan, on May 27, becoming the first sitting American president to set foot in the city once devastated by a US atomic bomb, where he will again call for the world to rid itself of nuclear weapons.
That declaration rings hollow to critics who believe Mr Obama's plan to overhaul and upgrade the US nuclear arsenal is sparking a dangerous new arms race with China and Russia.
The modernization program, including purchases of new bombers and ballistic missile submarines, could cost as much as US$1 trillion over the next 30 years, said Lisbeth Gronlund, co-director of the Union of Concerned Scientists' Global Security Program.
"The plan to rebuild and refurbish every weapon that we have basically sort of throws the gauntlet down, and Russia and China feel like they have to match it," Ms Gronlund said in an interview.
"He has said really great things but his actions have not really been consistent with his words."
The White House said Mr Obama will not apologize for President Harry Truman's decision to use the bomb, which many Americans believe hastened the end of World War II and saved millions of US and Japanese lives.
He will instead "highlight his continued commitment to pursuing the peace and security of a world without nuclear weapons," White House Press Secretary Josh Earnest said in a statement.
Ms Gronlund's group has called for Mr Obama to scale back the overhaul and reduce the US arsenal.
Ellen O Tauscher, Mr Obama's former undersecretary of state for arms control, said she was "disappointed" that the president didn't push back against Pentagon plans to refurbish components of the US nuclear arsenal in ways that could make it more potent.
Ms Tauscher said she hasn't been persuaded by Pentagon arguments that all of the refurbished nuclear weapons are necessary and that conventional weapons can't achieve some of the same strategies.
"I'm not sold yet," she said in an interview. "Actually, I'm far from sold." There are about 1,900 warheads in the US nuclear arsenal, and under the modernization plan they would be refurbished or replaced, along with the bombers, missiles and submarines that can launch them, to last for the next 30 to 50 years, according to the Arms Control Association, a Washington nonprofit.
Mr Obama said last month that he is concerned that the overhaul could cause other countries to enhance their nuclear programs, but that he was striking the right balance to make sure the US nuclear stockpile is "safe" and "reliable."
"We have to make sure that our deterrence continues to work," Mr Obama said after his final Nuclear Security Summit in Washington last month. The president said Russia has undermined his efforts to promote denuclearization by refusing to participate.
Mr Earnest told reporters that Mr Obama has "worked aggressively" to sign agreements with Russia to reduce nuclear stockpiles, and that the deal his administration negotiated last year with Iran to unwind the country's nuclear program would "block proliferation".
"The president has made this issue, nuclear security, a top priority," Mr Earnest said. "Much of our work to refurbish our nuclear weapons stockpile has been conducted with the goal of ensuring the safety of those nuclear weapons but also enhancing their readiness. None of that detracts from the top-line goal the president has set out, which is to rid the world of nuclear weapons."
After a meeting of the Group of Seven leaders in Ise-Shima, Japan, Mr Obama will visit the Hiroshima Peace Memorial Park, which is dedicated to those who died during the bombing. Mr Obama won't make an apology for the US attack on the city.
"He will not revisit the decision to use the atomic bomb at the end of World War II," White House Deputy National Security Adviser Ben Rhodes said in a post on Medium.com.
"Instead, he will offer a forward-looking vision focused on our shared future." Mr Obama's trip follows recent visits by US Secretary of State John Kerry and US Ambassador to Japan Caroline Kennedy.
Japanese Prime Minister Shinzo Abe, who will accompany Mr Obama in Hiroshima, told reporters in Tokyo that the US president's visit would be an opportunity to pay respects to all the Americans and Japanese who lost their lives in the war.
The bombing of Hiroshima on Aug 6, 1945, and Nagasaki three days later, is widely seen in the US as having prevented a bloodier invasion of Japan and hastening the end of the Pacific War. The twin bombings killed more than 120,000 people instantly, and tens of thousands more died from injuries and exposure to radiation.
"Even without a presidential apology this visit breaks an important taboo, because it's hard to see how Obama can go to Hiroshima and talk about the need for a nuclear-free world without acknowledging the suffering inflicted by the atomic bombs," Tobias Harris, a Japan analyst at Teneo Intelligence in Washington, said in an e-mail.
The White House sought to pre-empt criticism that Mr Obama's visit would be, in effect, an apology for the bombings, which led to Japan's unconditional surrender and eventually the end of World War II.
"The United States will be eternally proud of our civilian leaders and the men and women of our armed forces who served in World War II for their sacrifice at a time of maximum peril to our country and our world," Mr Rhodes wrote. "Their cause was just, and we owe them a tremendous debt of gratitude."
Japan's armed forces haven't fired a shot in battle since the war, and the country has provided land and money for US military bases in return for the protection of its ally's nuclear umbrella.
Mr Obama's visit, and his call for a nuclear-free world, is likely to be well-received among the Japanese public. A survey of almost 900 atomic-bomb victims by the Yomiuri newspaper in March and April showed that 70 per cent of these "hibakusha" hoped that the US president would visit the city.
The trip, coming in the heat of a presidential election, is also likely to stir controversy in the US.
Donald Trump, the presumptive Republican presidential nominee, has indicated that Japan and South Korea should either pay the US more for American military deployments in their countries or be allowed to develop their own nuclear weapons.
Japan and South Korea are confronted by a regional threat as North Korea has pushed further this year in its pursuit of nuclear weapons.