Mr. Justice Stewart
delivered the opinion of the Court.
The petitioner, a Nashville lawyer, was convicted in the United States District Court for the Middle District of Tennessee upon one count of an indictment under 18 U. S. C. § 1503, which charged him with endeavoring to bribe a member of the jury panel in a prospective federal criminal trial. The conviction was affirmed by the Court of Appeals, 350 F. 2d 497. We granted certio-rari, 382 U. S. 1023, primarily to consider whether the conviction rests upon unconstitutionally acquired evidence, although the petitioner also presses other claims.
In late 1963, James R. Hoffa was awaiting trial upon a criminal charge in the federal court in Nashville, and the petitioner, as one of Hoffa’s attorneys, was engaged in preparing for that trial. In connection with these preparations the petitioner hired a man named Robert Vick to make background investigations of the people listed on the panel from which members of the jury for the Hoffa trial were to be drawn. Vick was a member of the Nashville police department whom the petitioner had employed for similar investigative work in connection with another criminal trial of the same defendant a year earlier. What the petitioner did not know was that Vick, before applying for the job with the petitioner in 1963, had met several times with federal agents and had agreed to report to them any “illegal activities” he might observe.
The conviction which we now review was upon the charge that the petitioner “during the period from on or about November 6, 1963, up to and including November 15, 1963, . . . did unlawfully, knowingly, wilfully and corruptly endeavor to influence, obstruct and impede the due administration of justice . . in that he “did request, counsel and direct Robert D. Vick to contact Ralph A. Elliott, who was, and was known by the said Osborn to be, a member of the petit jury panel from which the petit jury to hear the [Hoffa] trial was scheduled to be drawn, and to offer and promise to pay the said Ralph A. Elliott $10,000 to induce the said Elliott to vote for an acquittal, if the said Elliott should be selected to sit on the petit jury in the said trial.” The primary evidence against the petitioner on this charge consisted of Vick’s testimony, a tape recording of a conversation between the petitioner and Vick, and admissions which the petitioner had made during the course of federal disbarment proceedings.
Vick testified that during a discussion with the petitioner at the latter’s office on November 7, he mentioned that he knew some of the prospective jurors. At this, according to Vick, the petitioner “jumped up,” and said, “You do? Why didn’t you tell me?” The two then moved outside into the adjacent alley to continue the conversation. There, Vick testified, he told the petitioner that one of the prospective jurors, Ralph Elliott, was his cousin, and the petitioner told Vick to pay a visit to Elliott to see what arrangements could be made about the case. Vick also testified to meetings with the petitioner on November 8 and November 11, when he told the petitioner, falsely, that he had visited Elliott and found him “susceptible to money for hanging this jury,” to which the petitioner responded by offering $5,000 to Elliott if he became a member of the jury and an additional $5,000 “when he hung the jury, but he would have to go all the way, and to assure Mr. Elliott that he would not be alone, that there would be some other jurors in there.”
I.
No claim is made in this case that Vick’s testimony about the petitioner’s incriminating statements was inadmissible in evidence. Cf. Hoffa v. United States, ante, p. 293; Lewis v. United States, ante, p. 206. What is challenged is the introduction in evidence of a tape recording of one of the conversations about which Vick testified, specifically the conversation which took place in the petitioner’s office on November 11. The recording of this conversation was played for the jury, and a written transcript of it was introduced in evidence. We are asked to hold that the recording should have been excluded, either upon constitutional grounds, Weeks v. United States, 232 U. S. 383, or in the exercise of our supervisory power over the federal courts. McNabb v. United States, 318 U. S. 332.
There is no question of the accuracy of the recording. The petitioner testified that it was a “substantially correct” reproduction of what took place in his office on November 11. There can be no doubt, either, of the recording’s probative relevance. It provided strong corroboration of the truth of the charge against the petitioner. The recording was made by means of a device concealed upon Vick’s person during the November 11 meeting. We thus deal here not with surreptitious surveillance of a private conversation by an outsider, cf. Silverman v. United States, 365 U. S. 505, but, as in Lopez v. United States, 373 U. S. 427, with the use by one party of a device to make an accurate record of a conversation about which that party later testified. Unless Lopez v. United States is to be disregarded, therefore, the petitioner cannot prevail.
But we need not rest our decision here upon the broad foundation of the Court’s opinion in Lopez, because it is evident that the circumstances under which the tape recording was obtained in this case fall within the narrower compass of the Lopez concurring and dissenting opinions. Accordingly, it is appropriate to set out with some precision what these circumstances were.
Immediately after his November 7 meeting with the petitioner, at which, according to Vick, the possibility of approaching the juror Elliott was first discussed, Vick reported the conversation to an agent of the United States Department of Justice. Vick was then requested to put his report in the form of a written statement under oath, which he did. The following day this sworn statement was shown by government attorneys to the two judges of the Federal District Court, Chief Judge Miller and Judge Gray. After considering this affidavit, the judges agreed to authorize agents of the Federal Bureau of Investigation to conceal a recorder on Vick’s person in order to determine from recordings of further conversations between Vick and the petitioner whether the statements in Vick’s affidavit were true. It was this judicial authorization which ultimately led to the recording here in question.
The issue here, therefore, is not the permissibility of “indiscriminate use of such devices in law enforcement,” but the permissibility of using such a device under the most precise and discriminate circumstances, circumstances which fully met the “requirement of particu- / larity” which the dissenting opinion in Lopez found necessary.
The situation which faced the two judges of the District Court when they were presented with Vick’s affidavit on November 8, and the motivations which prompted their authorization of the recorder are re-fleeted in the words of Chief Judge Miller. As he put it, “The affidavit contained information which reflected seriously upon a member of the bar of this court, who had practiced in my court ever since I have been on the bench. I decided that some action had to be taken to determine whether this information was correct or whether it was false. It was the most serious problem that I have had to deal with since I have been on the bench. I could not sweep it under the rug.”
So it was that, in response to a detailed factual affidavit alleging the commission of a specific criminal offense directly and immediately affecting the administration of justice in the federal court, the judges of that court jointly authorized the use of a recording device for the narrow and particularized purpose of ascertaining the truth of the affidavit’s allegations. As the district judges recognized, it was imperative to determine whether the integrity of their court was being undermined, and highly undesirable that this determination should hinge on the inconclusive outcome of a testimonial contest between the only two people in the world' who knew the truth — one an informer, the other a lawyer of previous good repute. There could hardly be a clearer example of “ The procedure of antecedent justification before a magistrate that is central to the Fourth Amendment’ ” as “a precondition of lawful electronic surveillance.”
We hold on these facts that the use of the recording device was permissible, and consequently that the recording itself was properly admitted as evidence at the petitioner’s trial.
II.
The petitioner’s defense was one of entrapment, and he renews here the contention made in his motion for acquittal at the trial that entrapment was established as a matter of law. We cannot agree.
The validity of the entrapment defense depended upon what had transpired at the meetings between the petitioner and Vick which took place before the recorded conversation of November 11. According to the petitioner, Vick initiated the idea of making a corrupt approach to Elliott on October 28, and the petitioner at first resisted the suggestion and tried to discourage Vick from carrying it out. The petitioner conceded that he ultimately acquiesced in the scheme, out of “weakness” and because he was exhausted from overwork, but said that he never seriously intended actually to carry out the plan to bribe Elliott. But Vick’s version of what had happened was, as stated above, quite different, and the truth of the matter was for the jury to determine. Masciale v. United States, 356 U. S. 386. Surely it was not a “trap for the unwary innocent,” Sherman v. United States, 356 U. S. 369, 372, for Vick to tell the petitioner, truthfully, that he knew some of the members of the jury panel and that one of them was his cousin. And according to Vick he had said no more when the petitioner “jumped up,” went out into the alley with him, and initiated the effort to get Elliott “on our side.” At the most, Vick’s statement afforded the petitioner “opportunities or facilities” for the commission of a criminal offense, and that is a far cry from entrapment. Sherman v. United States, supra, at 372; Sorrells v. United States, 287 U. S. 435, 441.
III.
Finally, the argument is made that even if the admissibility and truth of all the evidence against the petitioner be accepted, this conviction must be set aside because his conduct did not constitute a violation of 18 U. S. C. § 1503. The basis for this argument is that since Vick never in fact approached Elliott and never intended to do so, any endeavor on the petitioner’s part was impossible of accomplishment.
We reject the argument. Whatever continuing validity the doctrine of “impossibility,” with all its subtleties, may continue to have in the law of criminal attempt, that body of law is inapplicable here. The statute under which the petitioner was convicted makes an offense of any proscribed “endeavor.” And almost 50 years ago this Court pointed out the significance of that word: “The word of the section is 'endeavor/ and by using it the section got rid of the technicalities which might be urged as besetting the word 'attempt/ and it describes any effort or essay to accomplish the evil purpose that the section was enacted to prevent. . . . The section ... is not directed at success in corrupting a juror but at the 'endeavor’ to do so. Experimental approaches to the corruption of a juror are the 'endeavor’ of the section.” United States v. Russell, 255 U. S. 138, 143.
If the evidence against the petitioner be accepted, there can be no question that he corruptly endeavored to impede the due administration of justice by instructing Robert Vick to offer a bribe to a prospective juror in a federal criminal case. , „ ,
, „ , Affirmed.
Mr. Justice White took no part in the consideration or decision of this case.
APPENDIX TO OPINION OF THE COURT.
Transcript of the recording of the Vick-Osborn conversation of November 11, 1963:
“Girl: You can go in now.
“Vick: O. K. honey. Hello, Mr. Osborn.
“Osborn: Hello Bob, close the door, my friend, and let's see what's up.
“Vick: How’re you doing?
“Osborn: No good. How're you doing?
“Vick: Oh, pretty good. You want to talk in here?
“Osborn: How far did you go?
“Vick: Well, pretty far.
“Osborn: Maybe we’d better . . .
“Vick: Whatever you say. Don’t make any difference to me.
“Osborn: [Inaudible whisper.]
“Vick: I’m comfortable, but er, this chair sits good, but we’ll take off if you want to, but
“Osborn: Did you talk to him?
“Vick: Huh?
“Osborn: Did you talk to him?
“Vick: Yeah. I went down to Springfield Saturday morning and talked to er.
“Osborn: Elliott?
“Vick: Elliott.
“Osborn: [Inaudible whisper.]
“Vick: Huh?
“Osborn: Is there any chance in the world that he would report you?
“Vick: That he will report me to the FBI? Why of course, there's always a chance, but I wouldn’t got into it if I thought it was very, very great.
“Osborn: [Laughed.]
“Vick: You understand that.
“Osborn: [Laughing.] Yeah, I do know. Old Bob first.
“Vick: That’s right. 'Don’t worry. I’m gonna take care of old Bob and I know, and of course I’m depending on you to take care of old Bob if anything, if anything goes wrong.
“Osborn: I am. I am. Why certainly.
“Vick: Er, we had coffee Saturday morning and now he had previously told you that it’s the son.
“Osborn: It is?
“Vick: Yes, and not the father.
“Osborn: That’s right.
“Vick: The son is Ralph Alden Elliott and the father is Ralph Donnal. Alden is er — Marie, that’s Ralph’s wife who killed herself. That was her maiden name, Alden, see? Anyway, we had coffee and he’s been on a hung jury up here this week, see?
“Osborn: I know that.
“Vick: Well, I didn’t know that but anyway, he brought that up so he got to talking about the last Hoffa case being hung, you know, and some guy refused $10,000 to hang it, see, and he said the guy was crazy, he should’ve took it, you know, and so we talked about and so just discreetly, you know, and course I’m really playing this thing slow, that’s the reason I asked you if you wanted a lawyer down there to handle it or you wanted me to handle it, cause I’m gonna play it easy.
“Osborn: The less people, the better.
“Vick: That’s right. Well, I’m gonna play it slow and easy myself and er, anyway, we talked about er, something about five thousand now and five thousand later, see, so he did, he brought up five thousand see, and talking about about [sic] how they pay it off you know and things like that. I don’t know whether he suspected why I was there or not cause I don’t just drop out of the blue to visit him socially, you know. We’re friends, close kin, cousins, but I don’t ordinarily just, we don’t fraternize, you know, and er, so he seemed very receptive for er, to hang the thing for five now and five later. Now, er, I thought I would report back to you and see what you say.
“Osborn: That’s fine! The thing to do is set it up for a point later so you won’t be running back and forth.
“Vick: Yeah.
“Osborn: Then tell him it’s a deal.
“Vick: It’s what?
“Osborn: That it’s a deal. What we’ll have to do— when it gets down to the trial date, when we know the date, tomorrow for example if the Supreme Court rules against us, well within a week we’ll know when the trial comes. Then he has to be certain that when he gets on, he’s got to know that he’ll just be talking to you and nobody else. -
“Vick: Social strictly.
“Osborn: Oh yeah.
“Vick: I’ve got my story all fixed on that.
“Osborn: Then he will have to know where to, he will have to know where to come.
“Vick: Well, er . . .
“Osborn: And, he’ll have to know when.
“Vick: Er, do you want to see him yourself? You want me to handle it or what?
“Osborn: Uh huh. You’re gonna handle it yourself.
“Vick: All right. You want to know it when he’s ready, when I think he’s ready for the five thousand. Is that right?
“Osborn: Well no, when he gets on the panel, once he gets on the jury. Provided he gets on the panel.
“Vick: Yeah. Oh yeah. That’s right. That’s right. Well now, he’s on the number one.
“Osborn: I know, but now . . .
“Vick: But you don’t know that would be the one.
“Osborn: Well, I know this, that if we go to trial before that jury he’ll be on it but suppose the government challenges him over being on another hung jury.
“Vick: Oh, I see.
“Osborn: Where are we then?
“Vick: Oh, I see. I see.
“Osborn: So we have to be certain that he makes it on the jury.
“Vick: Well now, here’s one thing, Tommy. He’s a member of the CWA, see, and the Teamsters, or
“Osborn: Well, they’ll knock him off.
“Vick: Naw, they won’t. They’ve had a fight with the CWA, see?
“Osborn: I think everything looks perfect.
“Vick: I think it’s in our favor, see. I think that’ll work to our favor.
“Osborn: That’s why I’m so anxious that they accept him.
“Vick: I think they would, too. I don’t think they would have a reason in the world to. I don’t think that I’m under any surveillance or suspicion or anything like that.
“Osborn: I don’t think so.
“Vick: I don’t know. I don’t frankly think, since last year and since I told them I was through with the thing, I don’t think I have been. Now Fred,
“Osborn: I don’t think you have either.
“Vick: You know Fred and I may not [pause], he may be too suspicious and I may not be suspicious enough. I don’t know.
“Osborn: I think you’ve got it sized up exactly right.
“Vick: Well, I think so.
“Osborn: Now, you know you promised that fella that you would have nothing more to do with that case.
“Vick: That’s right.
“Osborn: At that time you had already checked on some of the jury that went into Miller’s court. You went ahead and did that.
“Vick: Well, here’s another thing, Tommy.
“Osborn: - church affiliations, background, occupation and that sort of thing on those that went into Miller’s court. You didn’t even touch them. You didn’t even investigate the people that were in Judge Gray’s court.
“Vick: Well, here’s the thing about it, Tommy. Soon as this damn thing’s over, they’re gonna kick my . . . out anyway, so probably Fred’s too. So, I might as well get out of it what I can. The way I look at it. I might be wrong cause the Tennessean is not gonna have anything to do with anybody that’s had anything to do with the case now or in the past, you know that. Cause they’re too close to the Kennedy’s.
“Osborn: All right, so we’ll leave it to you. The only thing to do would be to tell him, in other words your next contact with him would be to tell him if he wants that deal, he’s got it.
“Vick: O. K.
“Osborn: The only thing it depends upon is him being accepted on the jury. If the government challenges him there will be no deal.
“Vick: All right. If he is seated.
“Osborn: If he’s seated.
“Vick: He can expect five thousand then and
“Osborn: Immediately.
“Vick: Immediately and then five thousand when it’s hung. Is that right?
“Osborn: All the way, now!
“Vick: Oh, he’s got to stay all the way?
“Osborn: All the way.
“Vick: No swing. You don’t want him to swing like we discussed once before. You want him
“Osborn: Of course, he could be guided by his own b — , but that always leaves a question. The thing to do is just stick with his crowd. That way we’ll look better and maybe they’ll have to go to another trial if we get a pretty good count.
“Vick: Oh. Now, I’m going to play it just like you told me previously, to reassure him and keep him from getting panicky, you know. I have reason to believe that he won’t be alone, you know.
“Osborn: You assure him of that. 100%.
“Vick: And to keep any fears down that he might have, see?
“Osborn: Tell him there will be at least two others with him.
“Vick: Now, another thing, I want to ask you does John know anything. You know, I originally told John about me knowing.
“Osborn: He does not know one thing.
“Vick: He doesn’t know. O. K.
“Osborn: He’ll come in and recommend this man- and I’ll say well just let it alone, you know.
“Vick: Yeah. So he doesn’t know anything about this at all?
“Osborn: Nothing.
“Vick: Now he hasn’t seen me. When I first came here he was in here, see.
“Osborn: -We’ll keep it secret. The way we keep it safe is that nobody knows about it but you and me-where could they ever go?
“Vick: Well that’s it, I reckon, or I’ll probably go down there. See, I’m off tonight. I’m off Sunday and Monday, see. That’s why I talked to you yesterday. I had a notion to go down there yesterday cause I was off last night and I’m off again tonight.
“Osborn: It will be a week at least until we know the trial date.
“Vick: 0. K. You want to hold up doing anything further till we know.
“Osborn: Unless he should happen to give you a call and - something like that, then you just tell him, whenever you happen to run into him.
“Vick: Well, he’s not apt to call, cause see
“Osborn: You were very circumspect.
“Vick: Yeah. We haven’t talked really definite and I think he clearly understands. Now, he might, it seemed to me that maybe he thought I was joking or, you know.
“Osborn: That’s a good way to leave it, he’s the one that brought it up.
“Vick: That’s right.
“Osborn: -
“Vick: Well, I knew he would before I went down there.
“Osborn: Well,-
“Vick: Huh?
“Osborn: I’ll be talking to you.
“Vick: I’ll wait a day or two.
“Osborn: Yeah. I would.
“Vick: Before I contact him. Don’t want to seem anxious and er
“Osborn: -
“Vick: O. K. See you later.”
18 U. S. C. § 1503 provides as follows:
"Whoever corruptly, or by threats or force, or by any threatening letter or communication, endeavors to influence, intimidate, or impede any witness, in any court of the United States or before any United States commissioner or other committing magistrate, or any grand or petit juror, or officer in or of any court of the United States, or officer who may be serving at any examination or other proceeding before any United States commissioner or other committing magistrate, in the discharge of his duty, or injures any party or witness in his person or property on account of his attending or having attended such court or examination before such officer, commissioner, or other committing magistrate, or on account of his testifying or having testified to any matter pending therein, or injures any such grand or petit juror in his person or property on account of any verdict or indictment assented to by him, or on account of his being or having been such juror, or injures any such officer, commissioner, or other committing magistrate in his person or property on account of the performance of his official duties, or corruptly or by threats or force, or by any threatening letter or communication, influences, obstructs, or impedes, or endeavors to influence, obstruct, or impede, the due administration of justice, shall be fined not more than $5,000 or imprisoned not more than five years, or both.”
The indictment contained two other counts charging similar offenses with respect to the earlier trial of the same defendant. The Government dismissed one of these counts, and the petitioner was acquitted on the other.
A transcript of the recording is reproduced as an Appendix to this opinion.
It is argued that in Lopez the petitioner knew that the person to whom he offered a bribe was a federal officer. But, even assuming there might otherwise be some force to this distinction, it is enough to point out that in the present case the petitioner also knew he was talking to a law enforcement officer — a member of the Nashville police department.
The relevant portion of this affidavit was as follows:
“On November 7, 1963, I was in Mr. Osborn’s office going over the results of my investigation. I was aware that the jury panel which I had been investigating was the panel assigned to Judge William E. Miller. Mr. Osbom and I got into a discussion of the jury panel assigned to Judge Frank Gray, Jr. This jury panel list had previously been shown to me by John Polk, an investigator for Mr. Osborn. Polk told me at that time that he was investigating the jury panel assigned to Judge Gray. At that time, I mentioned to Polk that I knew three of the people on the jury panel. In discussing the panel with Mr. Osborn, I again mentioned that I knew three of the people on the jury panel. Mr. Osbom said, ‘You do? Why didn’t you tell me?’ I told Mr. Osbom I had told John Polk and assumed that John Polk had told him. Mr. Osborn said that Polk had not told him and suggested that we discuss the matter further. We then left Mr. Osborn’s office and walked out onto the street to discuss the matter further. Mr. Osborn asked me how well I knew the three prospective jurors. I told him that I knew Mr. Ralph A. Elliott, Springfield, Tennessee, the best since he was my cousin. Mr. Osborn asked me whether I knew him well enough to talk to him about anything. I said that I thought I did. Mr. Osborn then said, ‘Go contact him right away. Sit down and talk to him and get him on our side. We want him on the jury.’ I told Mr. Osbom that I thought Mr. Elliott was not in very good financial position and Mr. Osbom said, ‘Good, go see him right away.’ ”
The recording device did not operate properly on the occasion of Vick’s visit to the petitioner’s office on November 8, and Vick made a written statement of what occurred during that meeting. The government lawyers reported these circumstances to District Judge Miller, who then authorized the use of the recorder on November 11, under the same conditions:
“I said on that second occasion the same as I did on the first occasion: that the tape recorder should be used under proper surveillance, supervision, to see that it was not faked in any way, and to take every precaution to determine that it was used in a fair manner, so that we could get at the bottom of it and determine what the truth was.”
“I also share the opinion of Mr. Justice BrennaN that the fantastic advances in the field of electronic communication constitute a great danger to the privacy of the individual; that indiscriminate use of such devices in law enforcement raises grave constitutional questions under the Fourth and Fifth Amendments; and that these considerations impose a heavier responsibility on this Court in its supervision of the fairness of procedures in the federal court system. However, I do not believe that, as a result, all uses of such devices should be proscribed either as unconstitutional or as unfair law enforcement methods.” Lopez v. United States, 373 U. S., at 441 (concurring opinion of The Chief Justice).
373 U. S., at 463.
“The requirements of the Fourth Amendment are not inflexible, or obtusely unyielding to the legitimate needs of law enforcement. It is at least clear that 'the procedure of antecedent justification before a magistrate that is central to the Fourth Amendment,’ Ohio ex rel. Eaton v. Price, 364 U. S. 263, 272 (separate opinion) ; see McDonald v. United States, 335 U. S. 451, 455; Abel v. United States, 362 U. S. 217, 251-252 (dissenting opinion), could be made a precondition of lawful electronic surveillance. . . .” Lopez v. United States, 373 U. S., at 464 (dissenting opinion of Mr. Justice BRENNAN).
The petitioner’s trial counsel explicitly conceded that the entrapment issue was for the jury to resolve.
The petitioner further argues, with respect to the entrapment defense, that the jury instructions were erroneous in two respects, and that government rebuttal evidence was improperly received.
It is urged that the trial judge committed error in failing to instruct the jury that if they acquitted the petitioner under Count 2 (charging an endeavor to bribe a juror at the 1962 Hoffa trial), they must not consider any evidence under that count in determining the petitioner’s guilt under Count 1. Such an instruction was not requested. Rule 30, Fed. Rules Crim. Proc. Moreover, it is settled that when the defense of entrapment is raised, evidence of prior conduct tending to show the defendant’s predisposition to commit the offense charged is admissible. See Sorrells v. United States, 287 U. S. 435, 451.
The petitioner further argues that the instructions on entrapment erroneously left to the jury the question of whether the tape recording had been obtained by lawful means. We do not so understand the trial judge’s language, and neither, apparently, did trial counsel, because no objection was made to the instructions as given. Rule 30, Fed. Rules Crim. Proc. Moreover, such an instruction would have been favorable to the petitioner, because the judge, in denying the earlier defense motion to suppress, had already ruled that the recording had been lawfully obtained.
Finally, objection is made to permitting the Government on rebuttal to introduce Vick’s November 8 affidavit and show the circumstances under which the tape recording had been authorized by the judges. But this evidence was a relevant response to the petitioner’s testimony that it was Vick who, at the instigation of the Government, had initiated the plan to approach Elliott as early as October 28.
See n. 1, supra.
Compare People v. Jaffe, 185 N. Y. 497, 78 N. E. 169, with People v. Gardner, 144 N. Y. 119, 38 N. E. 1003. See Wechsler, Jones & Korn, The Treatment of Inchoate Crimes in the Model Penal Code of the American Law Institute: Attempt, Solicitation, and Conspiracy, 61 Col. L. Rev. 571, 578-585 (1961).