Every August 6th and 9th, the nation's conscience is stirred--and, for many citizens, haunted--by what America did to Hiroshima and Nagasaki on those dates in 1945.

Historically, we remember this destruction of 37 summers ago because no persuasive case has ever been made that the atomic bombings were militarily necessary. Arguments for the moral necessity for the two mass killings have never been advanced. I have met World War II veterans who claim they would have been killed by Colman McCarthy the Japanese if we had not dropped the bombs. But this we-had-to-get-them-first argument has never been accepted by serious scholars. Japan's military was all but collapsed by August 1945. We knew it, but we killed anyway.

Why go into all this again? A fair question, except that the issue has never left us. A war didn't end in 1945. An era began.

In the June issue of the Journal of Epidemiology and Community Health, Dr. Alice Stewart, a British physician whose record for thorough research commands trust, reports that studies have been underestimating the residual effects of the Hiroshima and Nagasaki bombings. It had been believed, from earlier studies, that cancer deaths were the sole delayed effects of the radiation.

Stewart determined that 4,339 deaths between 1950 and 1974 were caused by A-bomb radiation. Two-thirds of the bomb survivors died of diseases other than cancer, including blood diseases. This contrasts with the earlier finding that only 415 had died, and all from cancer.

In the radiation debate, Stewart's conclusions--that the death rate is 10 times greater than had been believed--mean that the public hasn't been given the full story on nuclear destructiveness. The Defense Department itself has been using the earlier, more benign findings to guess the radiation aftereffects of nuclear war. The department's message--it won't be all that bad--has been discredited.

This is a small victory and, at that, won by a lone British doctor who is 77 years old. But against the unprecedented domination that the weapons industry enjoys in both American and international politics, any information that can lead to new controls is a major advance. The nuclear-freeze campaign has shown that citizens can be shaken out of their complacency. But weapons apologists know how to wait out the uproar. They have done that with the MX missile. For a time, the citizens of Utah and Nevada became a bronco that bucked the military from its back. But plans for the MX someplace else proceed at a steady pace.

With the planet Earth turning into the bomb factory of the universe, and with nation states evolving into weapon states, the nuclear era that began in 1945 has turned the meaning of war on its head. Before a nuclear power ever gets to destroy what it believes is an enemy nation, it has already begun to destroy itself.

In the new book, "Killing Our Own," Harvey Wasserman and Norman Solomon document the effects of radiation from bomb tests, weapons production, waste storage and power reactors. Their research makes a mockery of leaders who talk of defeating the other side through "limited exchanges." It would not "make much difference," the authors state, "where the bombs landed. Four days after the Chinese exploded a bomb on their own soil in September 1976, dangerous levels of radiation were recorded in milk throughout New England. The radioactive cloud circled the globe and was monitored as it passed over the East Coast of the United States a second time, several days later. An American attack on the Soviet Union or a Soviet attack on America would ultimately have the same impact on future generations in each country. And bombs manufactured and used, or reactors blown up in smaller countries, will ultimately kill and maim the children of the nation that sold them the technology."

The 37 years since Hiroshima and Nagasaki have been marked by the illusion that the world has been free of nuclear war. But William James wrote that the "preparation for a war by nations is the real war." That might seem like the musings of a philosopher, except that the radiation victims are everywhere--from China to New England.