In a display of shameless hypocrisy, the leaders of the G7 group of the major powers—the US, Britain, France, Germany, Japan, Italy and Canada—laid wreaths yesterday at the Cenotaph for the Atomic Bomb Victims in the Peace Memorial Park in Hiroshima, Japan prior to their summit this weekend.

Far from the ceremony signifying a pledge to never use nuclear weapons again, the imperialist cabal is focussed on the rapidly escalating NATO conflict against Russia in Ukraine and accelerating US confrontation with China, which threaten to engulf humanity in a nuclear holocaust.

Like President Obama, the first American leader to visit Hiroshima since the end of World War II, President Biden made clear in advance that no apology would be forthcoming for the monstrous war crime carried out by US imperialism on August 6, 1945. His refusal to offer even a token acknowledgement of the criminality of the dropping of atomic bombs on Hiroshima, and three days later on Nagasaki, is a sharp warning that the US will use nuclear weapons again to prosecute its strategic interests.

The horrific scale of death and destruction in Hiroshima and Nagasaki is an ominous reminder of what is at stake as the US and its allies accelerate the plunge toward a global conflict.

The atomic bomb, code-named “Little Boy,” dropped on Hiroshima, a city of a quarter of a million people, exploded with a force equivalent to between 15 and 20 kilotons of TNT. It killed an estimated 80,000 instantly, or within hours, who died as a result of terrible burns and injuries as the shockwave levelled the city and triggered a firestorm.

Survivors described gruesome scenes. One wrote: “Hundreds of those still alive… wandering around vacantly. Some were half-dead, writhing in their misery… They were no more than living corpses.”

Another 40,000 people died outright in Nagasaki. The deaths continued to climb in the following days and weeks as men, women and children succumbed to burns, injuries and radiation sickness. Estimates put the death toll in the immediate aftermath at between 250,000 and 300,000—90 percent of them civilians.

World War II had already witnessed atrocities on a scale previously unimagined, including the Nazi regime’s systematic murder of six million Jews and the Japanese army’s slaughter of up to 300,000 captured Chinese soldiers and civilians in Nanjing. Yet the barbaric mass murder of civilians in Hiroshima and Nagasaki stands out as a cold-blooded and calculated atrocity that lacked any military necessity and was motivated solely by US imperialism’s ambitions for post-war global domination.

Washington justified its criminal decision on the basis of lies. It claimed that the use of atomic weapons was necessary to save the American lives that would be lost in a wholesale invasion of Japan. Yet by August 1945, Japanese imperialism was on its knees, isolated by the defeat of its ally Germany and defenceless against relentless US air raids, which included the firebombing of Tokyo in March 1945, which killed more than 300,000 people. Japan was already suing for peace and seeking terms for surrender through intermediaries.

The atomic bombings were terrorist actions aimed not only at intimidating the people of Japan, but the world at large, above all the Soviet Union, which had ended its neutrality pact with Tokyo and was about to enter the war in the Pacific. The US was determined to use its newly acquired weapons of mass destruction not only to force the immediate, unconditional surrender of Japan, but to put its stamp on the uncertain and unstable world that was emerging with the end of the war.

The danger of a catastrophic nuclear war today is higher than at any time since World War II. In its historic decline, US imperialism has resorted to military aggression again and again over the past three decades in Central Asia, the Middle East, North Africa and the Balkans in a desperate and reckless bid to shore up its global position. Having failed to achieve its objectives through these criminal adventures, the US and its allies are engaged in a war with Russia in Ukraine—that is, a war between nuclear-armed powers.

The G7 summit takes place as NATO funnels weaponry into Ukraine in ever-greater quantities, sophistication and destructive power—the latest being battle tanks, long-range cruise missiles and now F-16 fighter aircraft—with reckless disregard of the danger of the conflict widening into a direct war between NATO and Russia. At the same time, the US is ratcheting up its provocations against China over Taiwan, seeking to goad Beijing into a debilitating war in the same way that it provoked the Russian invasion of Ukraine.

Each G7 member is seeking to stake its claim amid the headlong US drive for global hegemony and is rapidly expanding its own military apparatus. Germany and Japan have both thrown off the legal and constitutional limitations put in place after their defeats in World War II and have doubled their military budgets over the past year since the start of the Ukraine war. Britain, which has played a central role in training and arming the Ukrainian armed forces, is boosting its defence spending. France is engaged in its own rapid military expansion.

Any suggestion that the sheer horror of what occurred in Hiroshima and Nagasaki in 1945 will stay the hands of nuclear-armed powers is delusional. US imperialism, which committed these atrocities, has never renounced a first strike use of nuclear weapons. Its latest Nuclear Posture Review, released last year, declared that US nuclear weapons “allow us to achieve Presidential objectives” should other means fail.

During his 2020 election campaign, Biden promised to make arms control and nuclear non-proliferation “a central pillar of US global leadership.” In office, however, he has continued to dismantle arms control agreements and provide tens of billions of dollars annually to the US military to modernise its nuclear arsenal and delivery systems. Last year Biden acknowledged that the world faced the “prospect of nuclear Armageddon,” but he has repeatedly declared that the US will not be deterred by nuclear threats.

Any resort to nuclear weapons would result in destruction and death on a scale that would make the atomic bombings of Hiroshima and Nagasaki pale by comparison. While strategic analysts in the Pentagon and US think tanks make ghoulish calculations to justify a limited nuclear war, the sheer scale of the US and Russian nuclear arsenals, consisting of thousands of nuclear weapons—each far more powerful than the two dropped on Japan—points to the danger of a nuclear holocaust sweeping the planet.

Just as the first use of atomic weapons on Japan was driven by imperialist ambitions, so the relentless and reckless drive by the US to war with Russia and China is guided by the same motivations. The international working class is the only social force that can prevent a Third World War involving nuclear weapons by abolishing the capitalist system and its outmoded division of the world into rival nation states. The building of a unified anti-war movement of the working class is the perspective for which the International Committee of the Fourth International and its youth organisation, the International Youth and Students for Social Equality, fight.