The Janus Faces of the Atomic Age : Bizarrely, the horridness of the weaponry seems to have promoted a nuclear peace

Day One of the Atomic Age began exactly 50 years ago, at 5:29 a.m., with an explosion of a test device in the New Mexico desert equal in power to 20,000 tons of TNT. Three weeks later the first atomic weapon ever used in wartime was dropped on Hiroshima, killing 118,661 people. Three days after that, the last atomic bomb ever used in wartime fell on Nagasaki, killing 73,884.

Within a week Japan surrendered to the United States and its allies. That the use of the two enormously destructive weapons sped the end of the war and forestalled an invasion that could have produced millions of American and Japanese casualties seems clear. That the horror of Hiroshima and Nagasaki contributed mightily to restraining any further use of nuclear weapons through more than 40 years of Cold War also seems clear.

No price tag can ever be put on the benefit of not fighting a nuclear war. It is simply impossible to quantify the value of the lives and property spared, the environmental poisoning prevented, the unbearable moral consequences not suffered thanks to the recognition among the nuclear powers that nuclear weapons may indeed be simply too terrible ever again to use against an enemy.

But keeping the nuclear peace for the last half-century has been staggeringly expensive. A new study by the Brookings Institution gives a good idea of what the nuclear arms race cost the United States alone.

The Brookings report estimates the total cost at nearly $4 trillion, an amount, coincidentally, close to the total national debt. Half of that was spent on the long-range bombers, land-based intercontinental bombers and nuclear-armed submarines that are the delivery systems for strategic weapons. About $1.1 trillion more went to command and control systems and air defenses. Nuclear warheads and bombs--about 70,000 of them have been produced--cost $375 billion.

The decades-old argument over how wisely this money was allocated is certain to be fueled by the new study. That the arms race was monstrously costly is beyond dispute. That it was also profligately wasteful in many of its aspects is clear. But any assessment must also take careful note of results. We have lived through the second half of the 20th Century without the unimaginably hideous experience of a nuclear war. Simply by their existence in such redundant numbers, the terrible weapons that could have destroyed much of the world may instead have contributed immeasurably to keeping the nuclear peace.