Hans Bethe: The other was M - A - D, MAD [Mutually Assured Destruction], which essentially says that nuclear weapons make sense only as a safeguard against nuclear weapons. As [Wolfgang] Panofsky has said recently, and there is actually an article by him, "It is not a doctrine. It is a fact of life. Nothing else is possible, whatever you might wish.” So I think you should not present it as something really unavoidable, without any movements in the opposite direction.
Martin Sherwin: Well, I think I did not make myself clear, because I do not believe that it was unavoidable, and I do not believe there were movements in the opposite direction. What I believe is that in spite of the movements in the opposite direction, the burden of the arms race has been from A-bombs to H-bombs to MIRVs [multiple independently targetable reentry vehicle].
Bethe: Right. First, missiles.
Sherwin: To missiles.
Bethe: To MIRV.
Sherwin: Surely, there are even more successes, in the sense that everything that has been proposed has not been developed. I mean, there were surely some things—
Bethe: Nothing important.
Sherwin: Nothing? That is depressing.
Bethe: The only important thing that was not done was ABM [anti-ballistic missile].
Sherwin: Was ABM. Okay. Now it seems to me that at the same time that MAD was put in, it was in that same administration, which understood the point that Panofsky made that we all agree with. He understood it intellectually, and articulated that point often in very convincing and moving prose. It still was the same administration that built up the tactical nuclear force in Europe, and not because it thought that limited nuclear war was a good idea. It did not. But when you mentioned your threat in 1961 during the Kennedy administration, you tend to, in a crisis, regardless of your intellectual framework, you tend to fall back on what you have available and reach for virtually everything that you have available.
Bethe: Very important point, and I think the '61 crisis is a very important one. Yes, I think that is—
Sherwin: Okay. Well, this has been tremendously helpful. If I ever give a talk something like this again it will be much better refined as a result.
Bethe: Now, you want to talk about this?
Sherwin: I would like to talk about basically [J. Robert] Oppenheimer in general, but I of course would like to start with—
Bethe: Oppenheimer in particular. The most important document is not here, namely the minutes of the October meeting.
Sherwin: Right. I did not want to bring them, because they were in the back of [Herbert] York's.
Bethe: Yes. Before you came, I was trying very hard to find York's book [The Advisors: Oppenheimer, Teller, and the Superbomb]. It is just too small.
Sherwin: Yes. These are not the minutes, but this is the report.
Sherwin: I actually may have the minutes too, but I thought what I would like to do is to get a running start on this meeting, to find out as much about the background as I could.
Bethe: I read this at one time, and it is awfully short.
Bethe: Isn't it?
Sherwin: It is very short. Well, there are three parts to it. This is the cover letter you are looking at. This is the letter to the Chairman of the Atomic Energy Commission, and that is in three parts and that was signed by Oppenheimer. This is the recommendation by [James] Conant, [Hartley] Rowe, [Cyril] Smith, [Lee] DuBridge, [Edward] Buckley and Oppenheimer. And the next one is the recommendation by [Enrico] Fermi and [Isidor] Rabi.
Bethe: Yes. Very good. I knew it was in there, and there is just so much more [to] the book than I remember.
Sherwin: Well, it made a large impact. So you think of it as a large book, but that is not the way—
Sherwin: It is a good book.
Bethe: It is a very good book. One of the reasons is that in this case, just as in the case of your book, I saw it first in manuscript when it was three times as big.
Bethe: You asked about the first page of the [Edward] Teller/[John] Von Neumann letter.
Sherwin: Right. November 23, 1949.
Bethe: August 23rd.
Sherwin: I mean, August 23rd. I am saying that to be sure that I can identify these things.
Bethe: Absolutely. You said the first page is not clear, and it is not clear to me either.
Bethe: The second page is certainly interesting. Certainly, he wanted to increase the use of atomic weapons. And that, I think, is the gist of it.
Sherwin: Of course, it is not unfair to say that that is sort of the gist of this whole orientation.
Sherwin: Life. Yes.
Bethe: I saw just recently an op-ed he wrote for the Washington Post. It must have been around April 28th. It is within two days either way, which makes absolutely no sense.
Sherwin: No sense in the context of other things he has recommended?
Bethe: No sense, period. It is an emotional plea to save the values of Western Civilization against the bad Russians. For this we have to go on developing atomic weapons, and he says, “There are certain people in the laboratories, young people, who are devoting their life to purely defensive atomic weapons. It would be terrible if one were to stop the activity.” I leave it to you to read.
Now, in the meeting of September, the following points struck my eye. On page ten, it mentions 60 kilotons, a high-yield weapon.
Bethe: Those were marvelous times, idyllic times.
Sherwin: Very small.
Sherwin: But three times the size of Hiroshima, yes?
Sherwin: That is the booster, isn’t it? Bomb?
Bethe: I am not sure that this was in their minds, but it is possible.
Sherwin: Although York says that the booster bomb could get up to half a megaton.
Bethe: It has been so tested.
Bethe: And even an unboosted bomb got off up to something like that.
Sherwin: That high?
Bethe: That high. It just was a question of putting in enough of the U-235.
Sherwin: Is that a combination of U-235 and plutonium?
Bethe: No plutonium.
Sherwin: No plutonium.
Bethe: The reason against plutonium is that once you come to a very large size, you get very high efficiency anyway. Plutonium and booster are methods to increase the efficiencies, which are very important for small amounts of material. Once you have very large bombs without H, the thing that matters is just the amount of material. You get the high efficiency anyway.
Sherwin: So U-235 can be exploded with an implosion device? It doesn't just need a gun device? But plutonium must be an implosion. It cannot be a gun.
Bethe: Correct. The gun is a silly way to do it anyway.
Sherwin: Once you know how to do implosion.
Bethe: Right. On page eleven, it is very interesting, the production at Hanford, that they have problems with leaving the material in long enough. You know what this means, megawatt-days per ton?
Sherwin: Well, I knew it was a period of time in terms of measuring.
Bethe: That is the period of time during which the uranium is left in the—
Sherwin: But I did not know what that time was.
Bethe: Well that you can figure out by knowing the power of the reactor and all of that, and it is not important. But what is important is that higher megawatt-days per ton means that some of the plutonium-239 is converted into 240, which makes pre-detonation. Apparently they were no longer worried about pre-detonation, but it was merely a question of production.
Sherwin: I see. Because the design had been figured out?
Bethe: Had been improved so much that—
Sherwin: Yeah, so that you could neutralize any of the 240.
Bethe: That you could stand a lot of 240.
Sherwin: Yes. In the way of what, of absorbing neutrons so that they do not—
Bethe: I refuse to comment.
Sherwin: Okay. I do not want to know how to build a bomb, anyway.
Bethe: On page nineteen, they make a big play on civil defense, which in that idyllic time made some sense talking about bombs in the number of tens, possibly going above 100 sometimes, talking about airplane delivery, and talking about bombs which at the most have 60 kilotons. So at that time the GAC [General Advisory Committee] was in favor of civil defense, which then made a great deal of sense, and now makes no sense whatever. When you talk about mindset, it is very important to realize that people's minds move in grooves, given by old history when that old history is no longer valid at all.
Sherwin: Yes. That is what I meant by [inaudible].
Bethe: Right. On page twenty, one thing says, “One outcome of the Russian explosion would be the achievement of a more rational security policy.” I presume that means policy on secrecy, security?
Sherwin: No. What they are saying is that one outcome of the release of the fact that the Russians had exploded a bomb would be a public discussion, and they believe that a public discussion would lead to a more rational policy.
Bethe: On secrecy?
Sherwin: Opening secrecy, yes.
Sherwin: No, it did not at all.
Sherwin: But that is because there was no debate.
Sherwin: It is interesting about Rabi's comment here. It says, "Rabi felt that the Russian achievement brought the prospect of war much closer, and therefore prompted the question as to what courses of action should be taken.”
Bethe: Yes. That is very interesting. Fortunately, he was wrong, and there was the contrary opinion of [Patrick] Blackett.
Sherwin: PMS Blackett.
Bethe: Yes. He said that the Russians would be more amenable to discussions once they had the atomic bomb.
Sherwin: Yes. Was that Blackett speaking publicly?
Bethe: Yes, it is in the book by him.
Sherwin: Fear, War, and the Bomb.
Sherwin: Yes, I know that. When you hooked it to this, I thought maybe these people in some way were talking to Blackett, which surprised me.
Bethe: Not at all. I remarked on the [Glenn] Seaborg letter. In that letter he took essentially [Harry] Truman's point of view that one cannot avoid developing the weapon.
Sherwin: Yes. Or, he said, you would have to hear some very good arguments.
Sherwin: Which I think he would have heard.
Bethe: Yes. I do not know whether he would have been satisfied.
Bethe: One important letter that I remember was that by Conant to Oppenheimer.
Sherwin: I remember a letter from Oppenheimer to Conant.
Bethe: There were both, in which Conant said, “If you recommend that we go ahead with the H-bomb, I do not want to have any part of it. I am completely opposed to that.”
Sherwin: That is interesting. I did not know about that.
Bethe: This should be in the Oppenheimer files.
Sherwin: It's not. I have been through the Conant papers and the Oppenheimer files.
Bethe: Yes, that is a great pity. When Teller and I jointly visited Oppenheimer, before the decision, before the October meeting, it must have been about two weeks earlier. Oppie had a letter from Conant which he showed both of us in which he made that statement. This was just on the right basis, namely, "Let's not escalate."
Sherwin: Do you remember anything else about the letter?
Bethe: No. It was about a page. It was stamped "Secret."
Sherwin: Everything gets stamped secret.
Bethe: Well, it had to be.
Sherwin: Yes, in that case it did. There are a lot of letters in the Oppenheimer papers which are secret, which are then declassified.
Sherwin: In a lot of the Conant files too.
Sherwin: But that letter, I know, is not there.
Bethe: I think it is a very important letter. I do not believe that it influenced Oppenheimer very much. Maybe it did, but it shows that Oppenheimer was not the only one who had this idea.
Bethe: When Teller and I discussed it with Oppenheimer, it was not at all clear to me that Oppenheimer was against developing the H-bomb. It was apparently clear to Teller, because at the end of that meeting Teller said to me, and he has published that statement, that he was convinced that now I would decide not to work on the H-bomb.
Sherwin: I thought that referred to a meeting with Oppenheimer after the October 29th meeting?
Bethe: Not so.
Sherwin: But before Truman's decision?
Bethe: Not so.
Sherwin: So this was before the October 29th meeting?
Bethe: Yes, before that meeting.
Sherwin: Was this in Princeton?
Bethe: In Princeton. We were both in Princeton. I do not remember why he [Teller] was in Princeton. I think he wanted to persuade Oppenheimer to participate in a crash program. I was in Princeton for a meeting of the Einstein Emergency Committee, and incidentally went to see Oppenheimer. I decided at that time, independently of what Oppenheimer had said, not to participate.
Sherwin But you also talked to [Victor] Weisskopf?
Bethe: Weisskopf and [George] Placzek.
Sherwin: And Placzek. Before this meeting or after this meeting?
Bethe: After the meeting with Oppenheimer. Weisskopf and Placzek and I speculated whether Oppenheimer would in the GAC favor the development or not. It was quite unclear to me where he stood.
Sherwin: Before I ask you this other question, I want to go back to that letter from Conant.
Sherwin: Since this conversation may be my only source if I cannot get ahold of the rest, tell me again what—
Bethe: What Conant said?
Sherwin: Yeah, and do you have any idea of the date? Did Oppenheimer just receive the letter that day?
Bethe: He had received it within the last few days. It was obviously written after the September meeting, because otherwise there would not have been any need for the letter. The date of our meeting I do not remember precisely. There may be records of the Emergency Committee of Atomic Scientists, which would determine that date, whether it was the 15th or the 20th of October, I do not know.
Sherwin: But you think it was closer towards the October meeting than it was towards the September meeting?
Bethe: That is my impression.
Sherwin: Okay. Do you think you are coming close to paraphrasing when you say that Conant said he did not want to have anything to do with the hydrogen bomb, or with the Committee?
Bethe: That is correct. No, with the hydrogen bomb.
Sherwin: If the Committee recommended it?
Sherwin: Meaning, that he would not work on it?
Bethe: No. Meaning that in the Committee, he would vote against it.
Sherwin: Oh, I see. Okay.
Bethe: Whatever Oppenheimer might do.
Sherwin: Right. Okay.
Bethe: That was clearly implied.
Sherwin: Did he give any reasons right there?
Bethe: I reconstructed that he did not want that. Atomic bombs were bad enough. He did not want to have any responsibility for furthering increasing the power.
Sherwin: Okay. That is very interesting. I have always thought, and if you think I am off-base please tell me, I thought that from the '46 period onward that Conant was a significant influence on Oppenheimer.
Bethe: That may well be.
Sherwin: That Oppenheimer found in Conant somebody whose judgement he could relate to.
Bethe: Yes, I think that is correct.
Conant was not the only one. Rabi was another, and Lauritsen, Charles Lauritsen. The other person who was mentioned in the Oppenheimer security trial, [Jerrold] Zacharias, I think had no influence on Oppie whatever. These three people, I think, did have considerable influence on him.
I had no influence on Oppenheimer whatever. I saw him occasionally, much more to listen than to talk to him. I do not believe he was very much interested in my judgement.
Sherwin: Is that right? Why do you say that?
Bethe: Except in scientific matters. He asked me to testify in the October meeting. He had great respect for my scientific judgement, including judgement on nuclear weapons feasibility. But I do not believe he had any particular interest in my political judgement.
Sherwin: Did you hesitate to make those judgments? Or did you find yourself disagreeing with him a lot?
Bethe: Not at all. No, I just thought that he had a much more mature opinion about these matters than I did.
Sherwin: I see.
Bethe: So I considered myself unqualified.
Sherwin: Could you tell me about when you testified? Was it on the first day, the 29th?
Sherwin: The morning or the afternoon?
Bethe: Probably the morning, but I do not know. The other people present were George Kennan.
Sherwin: Did you hear Kennan, or were you there just for your presentation?
Bethe: Just for my presentation. The meetings were very secret, so witnesses were brought in one by one. Kennan came out while I was sitting in the waiting room. I think I was the next witness. I was asked for my opinion on the feasibility of actually building the H-bomb. I think I probably would have said that it is uncertain, that there were some possibilities, but that it was by no means clear whether they would work.
Sherwin: Yes. They say in their report that it was a full commitment equivalent more or less to the Manhattan Project in a five-year period. I think they say that it might be a 50/50 chance, or something like that. Does that fit in with what you would have thought at that time?
Sherwin: Okay. Who else would have testified? Teller and [Robert] Serber?
Sherwin: No, Serber and [Luis] Alvarez, right? I think they both came from Berkeley.
Bethe: Alvarez, I did not meet in the anteroom. But Serber I did. Serber came right after me.
Sherwin: How long were you in there?
Bethe: Oh, a better part of an hour, I think. It was a long—
Sherwin: Did they ask you more than was it feasible?
Bethe: I did volunteer my opinion, that one should not do it.
Sherwin: Did they ask you why?
Bethe: Probably. Whether they asked me or not, I would have said.
Sherwin: Which was more or less the same reasons as Conant's?
Bethe: As Conant's, yes.
Sherwin: Yes. Were there other issues that—
Bethe: Just technical feasibility and what the decision should be. I think they mainly wanted to hear about the technical feasibility. Now, I have really said everything that I made notes on.
Oh, one more point. I was interested and troubled to read that [David] Lilienthal was apparently quite weak, and his health was so bad that it probably contributed to his ineffectiveness.
Sherwin: Yes. I think by this point, he had been so ground down.
Bethe: Right. By the [Senator Bourke] Hickenlooper investigation.
Sherwin: Yes, and overwhelmed by a sense of pessimism that you cannot stop these things.
Bethe: Yes. There is a very detailed Lilienthal diary. Which includes, I think, this time.
Sherwin: Yes, it does. In several volumes, three or four.
Bethe: Yes. But what I have seen only—
Sherwin: The Atomic Energy years?
Bethe: Not only restricted to that, but this particular time. I found it very interesting, and indeed, very pessimistic.
Sherwin: Yes. Let's see what we have here. Advisory Committee problems and Lilienthal’s remarks. These were just for your interest, if you wanted to see. Here we are, from the Gordon Dean diaries. Excerpts on February 9, 1951, and on February 12, 1951. Dean has comments to the effect that Oppenheimer has discouraged people from getting too enthusiastic about the program, whatever that means.
By 1951, what is, to the best of your recollection, Oppenheimer's view? It has been about a year and a month or so since Truman made the decision in January 1950. Did you have contact with him at that time?
Bethe: No useful contact. I presume that he still regretted Truman's decision. But that is just my extrapolation, and not by direct knowledge. In addition to that, of course, he had heard of the investigations by [Stanislaw] Ulam showing that the original so-called "Classical Super" would probably not work. I can well imagine that a number of people who asked Oppenheimer's opinion were told by him.
Sherwin: Yeah, he did not think much of it.
Bethe: Right. Now that changed, of course, in June of '51.
Sherwin: Yeah, w ith the Princeton meeting.
Bethe: The Princeton meeting.
Sherwin: Right. Were you at that meeting?
Bethe: Yes. Not only was I at that meeting, but I presented Teller's idea. Teller thought that it would be more effective with Oppenheimer and Rabi and a few others if I presented it. I was quite willing to do that. So the main presentation was my presentation, and then Teller chimed in and gave some details.
Sherwin: Now this put the whole thing on a different track. It was almost—and again, I am searching for an understanding of my own—would it be fair to say that it was almost like the Frisch–Peierls [Memorandum] insight for the atomic bomb?
Sherwin: That it was suddenly seen how this—
Bethe: This way, it can be done.
Sherwin: Could be done.
Bethe: Once it was clear how it could be done, it was indeed very obvious that presumably the Russians could do it, too.
Sherwin: Because it was so intermittently connected with the atomic bomb work?
Bethe: No, because it was an idea which once conceived, was almost sure to succeed.
Sherwin: Then I have two questions.
Sherwin: One goes back to your comments on the other side of the tape about a hydrogen bomb. It has to be tested, because of the nature of its complexity.
Sherwin: So the clarity was not equivalent to the clarity of the atomic bomb.
Bethe: The first atomic bomb had to be tested, too.
Sherwin: Well, the first implosion atomic bomb.
Bethe: The first implosion.
Sherwin: But not the first gun.
Bethe: Not the first gun. No, but the first implosion had to be tested too.
The question with the hydrogen bomb was similar, namely, would the method of assembly, which was now suggested by Teller, actually work? It was not obvious at all. The difference, however, between the H-bomb and the A-bomb is that the result is much more sensitive to the details of the assembly. Therefore, even when you know that it will work, and even if you know the great secret, it is still not at all clear that it will work in exactly the configuration.
Sherwin: So in other words, the technical problem for the hydrogen bomb is far more critical that it be done exactly right, than the technical problem with the atomic bomb?
Bethe: That is correct.
Sherwin: The second problem is another one of these A-bomb, H-bomb analogies. If the insight that the Teller-Ulam collaboration brought to the H-bomb was of the kind that once someone told it to you, you would say, "Of course," and everybody else would think of it too, the same thing was true during the war with the A-bomb.
Sherwin: Of course, we were two years behind the Germans. Now the Germans worked on it for two years in one way or another, and there are lots of reasons—
Bethe: Two plus, yes. [Inaudible] three than two.
Sherwin: Okay. They never got to first base, or at least not to December 1942, to Fermi’s [sustained nuclear reaction].
Bethe: They never did. No.
Sherwin: Yeah. Does that modify—bringing that analogy in? In other words, it is one thing to say that people thinking of this who are bright enough should think of it, but it does not necessarily have to happen that they will think of it. They will in time, of course, but at about the same time—
Bethe: That is a terribly important point. I will now trot out my favorite theory.
Let me first say that in 1954, I was asked, together with lots of other people, by the Congressional Joint Committee on Atomic Energy. It may have been '53 or maybe '54. I do not remember for sure. It was after the first supposed test of a Russian H-bomb, which was in August '53, which was not an H-bomb, and before the first real test, which was the end of '55.
In between these two events, and I do not recall exactly when, the Joint Committee asked a number of people connected with the developments, “When are the Russians likely to have one?”
So I wrote in a secret testimony, "I do not know," is what I wrote, “Because it depends on having an idea. When that idea will occur to them, nobody can tell. So it can be tomorrow, or it can be twenty years from now. It just is unpredictable.” Now I do not remember that testimony accurately, but that was the gist of it.
Bethe: My favorite theory was stated first by one of the British scientists working on an atomic weapons. They said, "We”—the British—"got the idea of how to do it by looking at the radioactive debris of the Russian test of '55." And indeed the British got it in '58, three years after they had the debris. That much is fact.
Hans Bethe: This Britisher said, “It took us three years after we got the idea. It took you three years after you started. So it probably took the Russians three years after they got your debris of ‘52.” So his opinion was that the Russian H-bomb was based on the debris, which they collected from our Pacific test of 1952.
Martin Sherwin: That is very interesting, because that takes us back to our initial discussion about not testing.
Sherwin: Because in the report that Oppenheimer, Conant, Fermi, and Rabi wrote, they said that “If we do it, it will simply make it easier for them to do it.”
Sherwin: Debris tells the story.
Bethe: The one thing is a fact, that the British got it because they looked at the Russian debris. The other is at least a very plausible theory.
Sherwin: Right. I guess the other argument is that the Russians went straight for it.
Bethe: That is the other argument.
Sherwin: What do you think of that?
Bethe: I do not know. I do not know. This British theory is so plausible with the timescale.
Sherwin: Yes. [Inaudible] have ‘55.
Sherwin: Mike is ‘52.
Bethe: Yes, and the British is ‘58. Now, it did not help the French. The French took ages before they got it.
It could be because while they have extremely good scientists, very few of them wanted to go into the weapons project. Which was not [inaudible] and surely not in the Soviet Union. That could be the explanation, but it took them an unconscionable time before they got it.
Sherwin: Was it ’67 or something?
Bethe: I think it was ’70, but I am not sure.
Sherwin: Well, that is the only encouraging fact, that at least as you go down the scale of industrial powers, that it gets harder.
Bethe: Yes. Now the Chinese, on the other hand, got it very quickly. The Chinese had their first weapon’s test, I think, sometime ’63, ’62.
Sherwin: During the Kennedy Administration.
Bethe: And they had their first H-bomb one or two years after. Now, they probably collected the Russian debris, among other things.
Sherwin: Yeah, and American debris and British debris. They had so much debris.
Bethe: Probably, the most likely, the Russian, because that comes directly over China. Be that as it may, even the fact that the Russians knew that we could do it, would help.
Bethe: Now the Russians, of course, have the eminent scientist, [Andrei] Sakharov. If he could leave the Soviet Union and could tell us, we would know a lot more.
Sherwin: Right. That’s one reason why he is probably not going to be able to leave.
Bethe: I do not see why the Russians would have any interest in concealing from us the way how they got started.
Sherwin: I think it is back to that point, habits of mind and people thinking, as you said, in track.
Bethe: That is right.
Sherwin: Just fear of people knowing anything.
Bethe: Yes, yes. Of course, there is a much simpler thing that the Russians do not tell us, which has presumably no military connotation at all. They made the radioactive contamination in the Urals, which was discussed so much by [Zhores] Medvedev.
Sherwin: I think I can understand sort of the bureaucracy’s anxieties about that, because in fact if it was an explosion or an accident—
Bethe: Right, there surely was not an explosion there. The most likely thing is that they were just very sloppy in their production and chemical separation.
But the Russians have a great interest in, as far as I can tell, making nuclear power respectable. They have said so many times. This is one of the things that is held against nuclear power. Medvedev claimed that it was an explosion in the waste disposal, which does not make any sense at all. So why do the Russians not tell the world what it actually was?
Sherwin: A ruse?
Bethe: In addition to it, I do not know about what year this was. It was long before [Leonid] Brezhnev. They could just say, “This was under the discredited former—“
Sherwin: I suppose if they ever say it, that is the context it will be in.