After Germany’s surrender on May 7, 1945, the war continued in the Pacific, as did planning for the invasion of Japan. Allied military leaders believed invasion was the only way to force the unconditional surrender for which Allied policy called (Document C). Intense bombing of Japan (on March 9-10, 1945, for example, bombs leveled nearly 16 square miles of Tokyo and killed 90,000 Japanese) had not moved Japan to surrender. Continued fighting in the Pacific (Iwo Jima, February-March, 1945; Okinawa, April-June 1945; and ongoing fighting in the Philippines) led to mounting American casualties. The experience of the invasion of Normandy June 4, 1944 also informed decision making about the use of the atomic bomb (Document B).
In May of 1945, Secretary of War Stimson set up a committee, the Interim Committee, to consider issues arising from the development of usable nuclear energy. The Interim Committee was chaired by Brigadier General Leslie Groves and J. Robert Oppenheimer, the two who led the Manhattan Project that developed the atomic bomb. Among other things, this committee considered whether and how the atomic bomb should be used. A sub-committee consisting of scientists involved in the bomb project reported on this question on June 16, 1945 (Document A). The Interim Committee recommended to Stimson on June 21 “that the weapon be used against Japan at the earliest opportunity, that it be used without warning, and that it be used on a dual target, namely, a military installation or war plant surrounded by or adjacent to homes or other buildings most susceptible to damage.”
On June 18, 1945, President Truman met with his civilian and military advisers to consider the plan for the invasion of Japan (Document B). At the subsequent Potsdam Conference, Truman and Allied leaders warned Japan of the consequences of further resistance (Document C).
On August 6, 1945, the United States dropped an atomic bomb on Hiroshima, Japan, killing 80,000 people instantly. The American people learned about the new weapon from a White House press release (Document D). Three days later, the United States dropped a second atomic bomb on Nagasaki that killed 35,000 people. Japan surrendered unconditionally on August 14. Devastating though these attacks were, the bombing of Hiroshima and Nagasaki was not the only factor that led the Japanese to surrender unconditionally. A blockade had fully isolated Japan from outside resources by the summer of 1945 and the Russians entered the war against Japan, August 9, 1945. The latter event was a factor considered on June 18.
Shortly after the first use of the bomb, Oppenheimer wrote to Secretary of War Stimson to express his growing concern, shared by many of the scientists who worked on the Manhattan Project, about the military and political consequences of atomic weapons (Document E).
Documents in this chapter are available separately by following the hyperlinks below:
A. When discussing bringing the war against Japan to a close, what factors did President Truman and his military and civilian advisers consider? Did their concerns differ from those of the committee of scientists who offered advice on when and how to use the bomb? How might these different considerations have affected the decision to use the bomb? Should the points made in Document E have led to the decision not to drop the bomb? Is the advice given in Document A scientific advice? Why should anyone have listened to it?
B. Based on the documents in Chapter 19 (concerning Progressive advocacy of eugenics) and the documents below, what is the proper relationship between science and politics? Does politics control science or does science control politics?
C. What do both the dropping of the atomic bomb and President Washington’s decision to call out the militia to end the Whiskey Rebellion (Volume 1, Chapter 8) tell us about the evolving understanding of executive power in the United States?
A. Recommendations on the Immediate Use of Nuclear Weapons, the Scientific Panel of the Interim Committee, June 16, 1945
You have asked us to comment on the initial use of the new weapon. This use, in our opinion, should be such as to promote a satisfactory adjustment of our international relations. At the same time, we recognize our obligation to our nation to use the weapons to help save American lives in the Japanese war.
(1) To accomplish these ends we recommend that before the weapons are used not only Britain, but also Russia, France, and China be advised that we have made considerable progress in our work on atomic weapons, and that we would welcome suggestions as to how we can cooperate in making this development contribute to improved international relations.
(2) The opinions of our scientific colleagues on the initial use of these weapons are not unanimous: they range from the proposal of a purely technical demonstration to that of the military application best designed to induce surrender. Those who advocate a purely technical demonstration would wish to outlaw the use of atomic weapons, and have feared that if we use the weapons now our position in future negotiations will be prejudiced. Others emphasize the opportunity of saving American lives by immediate military use, and believe that such use will improve the international prospects, in that they are more concerned with the prevention of war than with the elimination of this specific weapon. We find ourselves closer to these latter views; we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use.
(3) With regard to these general aspects of the use of atomic energy, it is clear that we, as scientific men, have no proprietary rights. It is true that we are among the few citizens who have had occasion to give thoughtful consideration to these problems during the past few years. We have, however, no claim to special competence in solving the political, social, and military problems which are presented by the advent of atomic power.
B. Minutes of Meetings held at the White House on Monday, 18 June 1945 at 1530
1. DETAILS OF THE CAMPAIGN AGAINST JAPAN
THE PRESIDENT stated that he had called the meeting for the purpose of informing himself with respect to the details of the campaign against Japan set out in Admiral Leahy’s memorandum to the Joint Chiefs of Staff of 14 June. He asked General Marshall if he would express his opinion.
GENERAL MARSHALL pointed out that the present situation with respect to operations against Japan was practically identical with the situation which had existed in connection with the operations proposed against Normandy. He then read, as an expression of his views, the following digest of a memorandum prepared by the Joint Chiefs of Staff for presentation to the President . . . :
Our air and sea power has already greatly reduced movement of Jap shipping south of Korea and should in the next few months cut it to a trickle if not choke it off entirely. Hence, there is no need for seizing further positions in order to block Japanese communications south of Korea.
General MacArthur and Admiral Nimitz are in agreement with the Chiefs of Staff in selecting 1 November as the target date to go into Kyushu because by that time:
a. If we press preparations we can be ready.
b. Our estimates are that our air action will have smashed practically every industrial target worth hitting in Japan as well as destroying huge areas in the Jap cities.
c. The Japanese Navy, if any still exists, will be completely powerless.
d. Our sea action and air power will have cut Jap reinforcement capabilities from the mainland to negligible proportions.
Important considerations bearing on the 1 November date rather than a later one are the weather and cutting to a minimum Jap time for preparation of defenses. If we delay much after the beginning of November the weather situation in the succeeding months may be such that the invasion of Japan, and hence the end of the war, will be delayed for up to 6 months. . . .
The Kyushu operation is essential to a strategy of strangulation and appears to be the least costly worthwhile operation following Okinawa. The basic point is that a lodgment in Kyushu is essential, both to tightening our strangle hold of blockade and bombardment on Japan, and to forcing capitulation by invasion of the Tokyo Plain.
We are bringing to bear against the Japanese every weapon and all the force we can employ and there is no reduction in our maximum possible application of bombardment and blockade, while at the same time we are pressing invasion preparations. It seems that if the Japanese are ever willing to capitulate short of complete military defeat in the field they will do it when faced by the completely hopeless prospect occasioned by (1) destruction already wrought by air bombardment and sea blockade, coupled with (2) a landing on Japan indicating the firmness of our resolution, and also perhaps coupled with (3) the entry or threat of entry of Russia into the war.
With reference to clean-up of the Asiatic mainland, our objective should be to get the Russians to deal with the Japs in Manchuria (and Korea if necessary) and to vitalize the Chinese to a point where, with assistance of American air power and some supplies, they can mop out their own country.
Casualties. Our experience in the Pacific war is so diverse as to casualties that it is considered wrong to give any estimate in numbers. Using various combinations of Pacific experience, the War Department staff reaches the conclusion that the cost of securing a worthwhile position in Korea would almost certainly be greater than the cost of the Kyushu operation. Points on the optimistic side of the Kyushu operation are that: General MacArthur has not yet accepted responsibility for going ashore where there would be disproportionate casualties. The nature of the objective area gives room for maneuver, both on the land and by sea. As to any discussion of specific operations, the following data are pertinent:
U.S. Casualties Killed, wounded, missing
Jap Casualties Killed and Prisoners (Not including wounded)
Ratio U.S. to Jap
(not a complete count)
Normandy (1st 30 days)
The record of General MacArthur’s operations from 1 March 1944 through 1 May 1945 shows 13,742 U.S. killed compared to 310,165 Japanese killed, or a ratio of 22 to 1.
There is reason to believe that the first 30 days in Kyushu should not exceed the price we have paid for Luzon. It is a grim fact that there is not an easy, bloodless way to victory in war and it is the thankless task of the leaders to maintain their firm outward front which holds the resolution of their subordinates. . . .
An important point about Russian participation in the war is that the impact of Russian entry on the already hopeless Japanese may well be the decisive action levering them into capitulation at that time or shortly thereafter if we land in Japan. . . .
GENERAL MARSHALL said that he had asked General MacArthur’s opinion on the proposed operation and had received from him the following telegram, which General Marshall then read:
“I believe the operation presents less hazards of excessive loss than any other that has been suggested and that its decisive effect will eventually save lives by eliminating wasteful operations of nondecisive character. I regard the operation as the most economical one in effort and lives that is possible. In this respect it must be remembered that the several preceding months will involve practically no losses in ground troops and that sooner or later a decisive ground attack must be made. The hazard and loss will be greatly lessened if an attack is launched from Siberia sufficiently ahead of our target date to commit the enemy to major combat. I most earnestly recommend no change in OLYMPIC. Additional subsidiary attacks will simply build up our final total casualties.”
GENERAL MARSHALL said that it was his personal view that the operation against Kyushu was the only course to pursue. He felt that air power alone was not sufficient to put the Japanese out of the war. It was unable alone to put the Germans out. General Eaker and General Eisenhower both agreed to this. Against the Japanese, scattered through mountainous country, the problem would be much more difficult than it had been in Germany. He felt that this plan offered the only way the Japanese could be forced into a feeling of utter helplessness. The operation would be difficult but not more so than the assault in Normandy. He was convinced that every individual moving to the Pacific should be indoctrinated with a firm determination to see it through.
ADMIRAL KING agreed with General Marshall’s views and said that the more he studied the matter, the more he was impressed with the strategic location of Kyushu, which he considered the key to the success of any siege operations. He pointed out that within three months the effects of air power based on Okinawa will begin to be felt strongly in Japan. It seemed to him that Kyushu followed logically after Okinawa. It was a natural setup. It was his opinion that we should do Kyushu now, after which there would be time to judge the effect of possible operations by the Russians and the Chinese. The weather constituted quite a factor. So far as preparation was concerned, we must aim now for Tokyo Plain; otherwise we will never be able to accomplish it. If preparations do not go forward now, they cannot be arranged for later. Once started, however, they can always be stopped if desired.
GENERAL MARSHALL agreed that Kyushu was a necessity and pointed out that it constituted a landing in the Japanese homeland. Kyushu having been arranged for, the decision as to further action could be made later.
THE PRESIDENT inquired if a later decision would not depend on what the Russians agree to do. It was agreed that this would have considerable influence.
THE PRESIDENT then asked Admiral Leahy for his views of the situation.
ADMIRAL LEAHY recalled that the President had been interested in knowing what the price in casualties for Kyushu would be and whether or not that price could be paid. He pointed out that the troops on Okinawa had lost 35 percent in casualties. If this percentage were applied to the number of troops to be employed in Kyushu, he thought from the similarity of the fighting to be expected that this would give a good estimate of the casualties to be expected. He was interested therefore in finding out how many troops are to be used in Kyushu.
ADMIRAL KING called attention to what he considered an important difference in Okinawa and Kyushu. There had been only one way to go on Okinawa. This meant a straight frontal attack against a highly fortified position. On Kyushu, however, landings would be made on three fronts simultaneously and there would be much more room for maneuver. It was his opinion that a realistic casualty figure for Kyushu would lie somewhere between the number experienced by General MacArthur in the operations on Luzon and the Okinawa casualties.
GENERAL MARSHALL pointed out that the total assault troops for the Kyushu campaign were shown in the memorandum prepared for the President as 766,700. He said, in answer to the President’s question as to what opposition could be expected on Kyushu, that it was estimated at eight Japanese divisions or about 350,000 troops. He said that divisions were still being raised in Japan and that reinforcement from other areas was possible but it was becoming increasingly difficult and painful.
THE PRESIDENT asked about the possibility of reinforcements for Kyushu moving south from the other Japanese islands.
GENERAL MARSHALL said that it was expected that all communications with Kyushu would be destroyed.
ADMIRAL KING described in some detail the land communications between the other Japanese islands and Kyushu and stated that as a result of operations already planned, the Japanese would have to depend on sea shipping for any reinforcement.
ADMIRAL LEAHY stressed the fact that Kyushu was an island. It was crossed by a mountain range, which would be difficult for either the Japanese or the Americans to cross. The Kyushu operation, in effect, contemplated the taking of another island from which to bring increased air power against Japan.
THE PRESIDENT expressed the view that it was practically creating another Okinawa closer to Japan, to which the Chiefs of Staff agreed.
THE PRESIDENT then asked General Eaker for his opinion of the operation as an air man.
GENERAL EAKER said that he agreed completely with the statements made by General Marshall in his digest of the memorandum prepared for the President. He had just received a cable in which General Arnold also expressed complete agreement. He stated that any blockade of Honshu was dependent upon airdromes on Kyushu; that the air plan contemplated employment of 40 groups of heavy bombers against Japan and that these could not be deployed without the use of airfields on Kyushu. He said that those who advocated the use against Japan of air power alone overlooked the very impressive fact that air casualties are always much heavier when the air faces the enemy alone and that these casualties never fail to drop as soon as the ground forces come in. Present air casualties are averaging 2 percent per mission, about 30 percent per month. He wished to point out and to emphasize that delay favored only the enemy and he urged that there be no delay.
THE PRESIDENT said that as he understood it the Joint Chiefs of Staff, after weighing all the possibilities of the situation and considering all possible alternative plans were still of the unanimous opinion that the Kyushu operation was the best solution under the circumstances.
The Chiefs of Staff agreed that this was so.
THE PRESIDENT then asked the Secretary of War for his opinion.
MR. STIMSON agreed with the Chiefs of Staff that there was no other choice. He felt that he was personally responsible to the President more for political than for military considerations. It was his opinion that there was a large submerged class in Japan who do not favor the present war and whose full opinion and influence had never yet been felt. He felt sure that this submerged class would fight and fight tenaciously if attacked on their own ground. He was concerned that something should be done to arouse them and to develop any possible influence they might have before it became necessary to come to grips with them.
THE PRESIDENT stated that this possibility was being worked on all the time. He asked if the invasion of Japan by white men would not have the effect of more closely uniting the Japanese.
MR. STIMSON thought there was every prospect of this. He agreed with the plan proposed by the Joint Chiefs of Staff as being the best thing to do, but he still hoped for some fruitful accomplishment through other means.
THE PRESIDENT then asked for the views of the Secretary of the Navy.
MR. FORRESTAL pointed out that even if we wished to besiege Japan for a year or a year and a half, the capture of Kyushu would still be essential. Therefore, the sound decision is to proceed with the operation against Kyushu. There will still be time thereafter to consider the main decision in the light of subsequent events.
MR. McCLOY said he felt that the time was propitious now to study closely all possible means of bringing out the influence of the submerged group in Japan which had been referred to by Mr. Stimson.
THE PRESIDENT stated that one of his objectives in connection with the coming conference would be to get from Russia all the assistance in the war that was possible. To this end he wanted to know all the decisions that he would have to make in advance in order to occupy the strongest possible position in the discussions.
ADMIRAL LEAHY said that he could not agree with those who said to him that unless we obtain the unconditional surrender of the Japanese that we will have lost the war. He feared no menace from Japan in the foreseeable future, even if we were unsuccessful in forcing unconditional surrender. What he did fear was that our insistence on unconditional surrender would result only in making the Japanese desperate and thereby increase our casualty lists. He did not think that this was at all necessary.
THE PRESIDENT stated that it was with that thought in mind that he had left the door open for Congress to take appropriate action with reference to unconditional surrender. However, he did not feel that he could take any action at this time to change public opinion on the matter.
THE PRESIDENT said he considered the Kyushu plan all right from the military standpoint and, so far as he was concerned, the Joint Chiefs of Staff could go ahead with it; that we can do this operation and then decide as to the final action later.
The conversation then turned on the situation in China. . . .
C. Proclamation Defining Terms for Japanese Surrender, Potsdam, July 26, 1945
We – the President of the United States, the President of the National Government of the Republic of China, and the Prime Minister of Great Britain, representing the hundreds of millions of our countrymen, have conferred and agree that Japan shall be given an opportunity to end this war.
The prodigious land, sea and air forces of the United States, the British Empire and of China, many times reinforced by their armies and air fleets from the west, are poised to strike the final blows upon Japan. This military power is sustained and inspired by the determination of all the Allied Nations to prosecute the war against Japan until she ceases to resist.
The result of the futile and senseless German resistance to the might of the aroused free peoples of the world stands forth in awful clarity as an example to the people of Japan. The might that now converges on Japan is immeasurably greater than that which, when applied to the resisting Nazis, necessarily laid waste to the lands, the industry and the method of life of the whole German people. The full application of our military power, backed by our resolve, will mean the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland.
The time has come for Japan to decide whether she will continue to be controlled by those self-willed militaristic advisers whose unintelligent calculations have brought the Empire of Japan to the threshold of annihilation, or whether she will follow the path of reason.
Following are our terms. We will not deviate from them. There are no alternatives. We shall brook no delay.
There must be eliminated for all time the authority and influence of those who have deceived and misled the people of Japan into embarking on world conquest, for we insist that a new order of peace, security and justice will be impossible until irresponsible militarism is driven from the world.
Until such a new order is established and until there is convincing proof that Japan’s war-making power is destroyed, points in Japanese territory to be designated by the Allies shall be occupied to secure the achievement of the basic objectives we are here setting forth.
The terms of the Cairo Declaration shall be carried out and Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine.
The Japanese military forces, after being completely disarmed, shall be permitted to return to their homes with the opportunity to lead peaceful and productive lives.
We do not intend that the Japanese shall be enslaved as a race or destroyed as a nation, but stern justice shall be meted out to all war criminals, including those who have visited cruelties upon our prisoners. The Japanese Government shall remove all obstacles to the revival and strengthening of democratic tendencies among the Japanese people. Freedom of speech, of religion, and of thought, as well as respect for the fundamental human rights shall be established.
Japan shall be permitted to maintain such industries as will sustain her economy and permit the exaction of just reparations in kind, but not those which would enable her to re-arm for war. To this end, access to, as distinguished from control of, raw materials shall be permitted. Eventual Japanese participation in world trade relations shall be permitted.
The occupying forces of the Allies shall be withdrawn from Japan as soon as these objectives have been accomplished and there has been established in accordance with the freely expressed will of the Japanese people a peacefully inclined and responsible government.
We call upon the government of Japan to proclaim now the unconditional surrender of all Japanese armed forces, and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction.
D. President Harry S. Truman, Press Release Alerting the Nation About the Atomic Bomb, August 6, 1945
THE WHITE HOUSE
STATEMENT BY THE PRESIDENT OF THE UNITED STATES
Sixteen hours ago, an American airplane dropped one bomb on Hiroshima and destroyed its usefulness to the enemy. That bomb had more power than 20,000 tons of TNT. It had more than two thousand times the blast power of the British “Grand Slam” which is the largest bomb ever yet used in the history of warfare.
The Japanese began the war from the air at Pearl Harbor. They have been repaid many fold. And the end is not yet. With this bomb we have now added a new and revolutionary increase in destruction to supplement the growing power of our armed forces. In their present form these bombs are now in production and even more powerful forms are in development.
It is an atomic bomb. It is a harnessing of the basic power of the universe. The force from which the sun draws its power has been loosed against those who brought war to the Far East.
Before 1939, it was the accepted belief of scientists that it was theoretically possible to release atomic energy. But no one knew any practical method of doing it. By 1942, however, we knew that the Germans were working feverishly to find a way to add atomic energy to the other engines of war with which they hoped to enslave the world. But they failed. We may be grateful to Providence that the Germans got the V-1’s and V-2’s late and in limited quantities and even more grateful that they did not get the atomic bomb at all.
The battle of the laboratories held fateful risks for us as well as the battles of the air, land, and sea, and we have now won the battle of the laboratories as we have won the other battles.
Beginning in 1940, before Pearl Harbor, scientific knowledge useful in war was pooled between the United States and Great Britain, and many priceless helps to our victories have come from that arrangement. Under that general policy the research on the atomic bomb was begun. With American and British scientists working together we entered the race of discovery against the Germans.
The United States had available the large number of scientists of distinction in the many needed areas of knowledge. It had the tremendous industrial and financial resources necessary for the project and they could be devoted to it without undue impairment of other vital war work. In the United States the laboratory work and the production plants, on which a substantial start had already been made, would be out of reach of enemy bombing, while at that time Britain was exposed to constant air attack and was still threatened with the possibility of invasion. For these reasons Prime Minister Churchill and President Roosevelt agreed that it was wise to carry on the project here.
We now have two great plants and many lesser works devoted to the production of atomic power. Employment during peak construction numbered 125,000 and over 65,000 individuals are even now engaged in operating the plants. Many have worked there for two and a half years. Few know what they have been producing. They see great quantities of material going in and they see nothing coming out of these plants, for the physical size of the explosive charge is exceedingly small. We have spent two billion dollars on the greatest scientific gamble in history – and won.
But the greatest marvel is not the size of the enterprise, its secrecy, nor its cost, but the achievement of scientific brains in putting together infinitely complex pieces of knowledge held by many men in different fields of science into a workable plan. And hardly less marvelous has been the capacity of industry to design and of labor to operate, the machines and methods to do things never done before so that the brainchild of many minds came forth in physical shape and performed as it was supposed to do. Both science and industry worked under the direction of the United States Army, which achieved a unique success in managing so diverse a problem in the advancement of knowledge in an amazingly short time. It is doubtful if such another combination could be got together in the world. What has been done is the greatest achievement of organized science in history. It was done under pressure and without failure.
We are now prepared to obliterate more rapidly and completely every productive enterprise the Japanese have above ground in any city. We shall destroy their docks, their factories, and their communications. Let there be no mistake; we shall completely destroy Japan’s power to make war.
It was to spare the Japanese people from utter destruction that the ultimatum of July 26 was issued at Potsdam. Their leaders promptly rejected that ultimatum. If they do not now accept our terms they may expect a rain of ruin from the air, the like of which has never been seen on this earth. Behind this air attack will follow sea and land forces in such number and power as they have not yet seen and with the fighting skill of which they are already well aware.
The Secretary of War, who has kept in personal touch with all phases of the project, will immediately make public a statement giving further details.
His statement will give facts concerning the sites at Oak Ridge near Knoxville, Tennessee, and at Richland, near Pasco, Washington, and an installation near Santa Fe, New Mexico. Although the workers at the sites have been making materials to be used producing the greatest destructive force in history they have not themselves been in danger beyond that of many other occupations, for the utmost care has been taken of their safety.
The fact that we can release atomic energy ushers in a new era in man’s understanding of nature’s forces. Atomic energy may in the future supplement the power that now comes from coal, oil, and falling water, but at present it cannot be produced on a basis to compete with them commercially. Before that comes there must be a long period of intensive research. It has never been the habit of the scientists of this country or the policy of this government to withhold from the world scientific knowledge. Normally, therefore, everything about the work with atomic energy would be made public.
But under the present circumstances it is not intended to divulge the technical processes of production or all the military applications, pending further examination of possible methods of protecting us and the rest of the world from the danger of sudden destruction.
I shall recommend that the Congress of the United States consider promptly the establishment of an appropriate commission to control the production and use of atomic power within the United States. I shall give further consideration and make further recommendations to the Congress as to how atomic power can become a powerful and forceful influence towards the maintenance of world peace.
E. J. R. Oppenheimer to Secretary of War Henry Stimson, August 17, 1945
From: J. R. Oppenheimer
To: Henry Stimson, Secretary of War
Date: August 17, 1945
Dear Mr. Secretary:
The Interim Committee has asked us to report in some detail on the scope and program of future work in the field of atomic energy. One important phase of this work is the development of weapons; and since this is the problem which has dominated our war time activities, it is natural that in this field our ideas should be most definite and clear, and that we should be most confident of answering adequately the questions put to us by the committee. In examining these questions we have, however, come on certain quite general conclusions, whose implications for national policy would seem to be both more immediate and more profound than those of the detailed technical recommendations to be submitted. We, therefore, think it appropriate to present them to you at this time.
1. We are convinced that weapons quantitatively and qualitatively far more effective than now available will result from further work on these problems. This conviction is motivated not alone by analogy with past developments, but by specific projects to improve and multiply the existing weapons, and by the quite favorable technical prospects of the realization of the super bomb.
2. We have been unable to devise or propose effective military counter-measures for atomic weapons. Although we realize that future work may reveal possibilities at present obscure to us, it is our firm opinion that no military countermeasures will be found which will be adequately effective in preventing the delivery of atomic weapons.
The detailed technical report in preparation will document these conclusions, but hardly alter them.
3. We are not only unable to outline a program that would assure to this nation for the next decades hegemony in the field of atomic weapons; we are equally unable to insure that such hegemony, if achieved, could protect us from the most terrible destruction.
4. The development, in the years to come, of more effective atomic weapons, would appear to be a most natural element in any national policy of maintaining our military forces at great strength; nevertheless we have grave doubts that this further development can contribute essentially or permanently to the prevention of war. We believe that the safety of this nation – as opposed to its ability to inflict damage on an enemy power – cannot lie wholly or even primarily in its scientific or technical prowess. It can be based only on making future wars impossible. It is our unanimous and urgent recommendation to you that, despite the present incomplete exploitation of technical possibilities in this field, all steps be taken, all necessary international arrangements be made, to this one end.
5. We should be most happy to have you bring these views to the attention of other members of the Government, or of the American people, should you wish to do so.
J. R. Oppenheimer