Truman Library, PSF–Subject File, “Atomic Weapons, Thermonuclear”
The Chairman of the Joint Congressional Committee on Atomic Energy (McMahon) to the President1
Dear Mr. President: More than two years ago you directed that the H-bomb program go forward.2 The historic Tightness of your decision, in the defense of our country and in the defense of peace, cannot be questioned. I write you today because I believe that further action is necessary by way of laying down requirements for H-bombs in quantity. Only the President of the United States should decide this issue.
It now seems likely that not merely one but several types of H-bombs can be constructed. The explosive power of each of these weapon types is expected to be equivalent to some millions of tons of TNT and very possibly tens of millions of tons of TNT. The early doubt whether this weapon could be made at all has almost disappeared. Likewise it seems that the weapon will be of manageable proportions from a delivery viewpoint, such that it could be carried in existing-type aircraft. A deliverable prototype H-bomb is anticipated by 1954 or sooner. The first A-bombs cost our nation about $2 billion; I estimate the first H-bombs may cost less than one tenth of this sum.
Since your original instructions two years ago had to do mainly with development efforts, my specific purpose in writing you is to recommend a new directive covering production efforts—how many H-bombs we need and how soon. As you know, certain questions on the scope and scale of the hydrogen program are now pending before the National Security Council, and some studies are underway. [Page 956] I very much hope that the problem will be met squarely in all of its implications for our defense.
A basic element in this problem is tactical uses. If the H-bomb is only a strategic weapon, then the number that could profitably be employed against an aggressor may be comparatively limited. If, however, this weapon is to have sweeping tactical applications against enemy military targets in case of war, then the number which we could profitably employ is apt to be very great.
A related question is the percentage of our existing and anticipated atomic stockpile that should be made available for hydrogen weapons. Ordinary A-bombs, of course, may be used to produce atomic explosions or else to set off vastly more powerful hydrogen explosions. Should 10 %, or 50%, or 90% of the atomic stockpile be assigned to the accumulation of a hydrogen stockpile? A third basic element in the problem is the estimated costs—over and above funds we already plan to spend on the atomic program—for manufacturing various numbers of H-bombs: For example, 100, 500, 1000, 1500, etc.
In other words, the fundamental issue is to what extent the H-bomb will be our primary nuclear weapon and the A-bomb a secondary or special-purpose weapon. I would not be of most help to you, as you confront the momentous problem of hydrogen requirements, unless I stated frankly my own belief that H-bombs can and must rapidly be made the primary weapon.
There are those who hesitate even to estimate military requirements until a specific hydrogen weapon type has been field-tested. It is true that we do not know today whether a particular H-bomb model will take out, for example, a circular area which has a radius of seven miles or only six miles. But, as I have noted, we have every expectation of achieving a deliverable prototype by 1954 that will introduce a new order of magnitude in firepower. To wait upon a prototype perfect in the last details before laying down quantity goals for H-bombs may well delay us two or three years.
I do not think anyone familiar with the technical facts can say that mass production of H-bombs within the next few years is beyond our capability. Cost figures of course contain a number of variables and uncertainties at the present time. I estimate, however, that a program designed to make the H-bomb our primary nuclear weapon would add perhaps $200 to $300 million annually to the expenditures we already contemplate for the Atomic Energy Commission. The important point is that the cost—relative to guns or tanks or planes or even to our present outlays for A-bombs—would be small. In my sincere judgment, the need is not huge funds—it is a bold decision to attain H-bombs in real quantity as quickly as possible.
[Page 957]It seems to me self-evident that, so long as the arms race continues, the ineluctable logic of our position leaves us without choice except to acquire the greatest possible firepower in the shortest possible time. It seems to me equally self-evident that the basic decisions on H-bomb requirements must be reached now.
Attached to this letter is a chronology which I had prepared on the leading events in the formulation of our atomic production policy over the past six years.3 The chronology is a long one, and some parts of it do not make for happy reading. In case you find it difficult to agree with the views expressed in this letter, I hope that you will not think it presumptuous of me to request that you and your highest counsellors read the attached paper. I profoundly hope that, six years hence, our military planners will be able to look back upon their recommendations in the hydrogen program and find satisfaction in the fact that some of the early delays encountered in the atomic program were not repeated.
I am sure I do not need to say that I write this letter with intense personal anguish. I share what I know are your own feelings of horror at the thought of these hideous weapons entering into the arsenals of the world. Yet overwhelming American superiority in H-bombs may well be the decisive means of keeping open the future for peace. It is one of the paradoxes of history that the President, who has worked harder and done more for world peace than any of his predecessors, has also been required—in behalf of peace—to meet the issue of hydrogen weapons.
If we carry on the fight for peace which you have launched, I remain convinced that we will yet win through to victory without war.
Very respectfully yours,
- A copy of this letter is in G/PM files, lot 68 D 349, “H-Bomb Report to the President”.↩
- For documentation on President Truman’s decision of Jan. 31, 1950, to proceed with the development of the hydrogen bomb, see Foreign Relations, 1949, vol. i, pp. 419 ff., and ibid., 1950, vol. i, pp. 493 ff.↩
- Not printed.↩