We granted certiorari to consider whether a trial court's order directing petitioner, the defendant in a federal prosecution, not to consult his attorney during a regular overnight recess, called while petitioner was on the stand as a witness and shortly before cross-examination was to begin, deprived him of the assistance of counsel in violation of the Sixth Amendment.

A grand jury in the Middle District of Florida returned indictments charging petitioner and several codefendants with conspiracy to import and illegal importation of a controlled substance into the United States, in violation of 18 U.S.C. § 371 and 21 U.S.C. § 952(a), and with possession of marihuana, in violation of 21 U.S.C. § 841(a). The charges grew out of plans for several of the defendants to fly about 1,000 pounds of marihuana from Colombia into the United States, plans that might have succeeded but for the fact that the pilot of the charter plane informed the United States Customs Service of the arrangements.

The trial of petitioner and one codefendant commenced on Tuesday, October 9, 1973. Petitioner testified in his own defense on Tuesday, October 16, and Wednesday, October 17. Petitioner's counsel concluded direct examination at 4:55 p. m. Tuesday. When the court recessed for the night, and after the jury departed, the prosecutor asked the judge to instruct petitioner not to discuss the case overnight with anyone. Throughout the trial, the judge had given the same instruction to every witness whose testimony was interrupted by a recess.

Petitioner's attorney objected, explaining that he believed he had a right to confer with his client about matters other than the imminent cross-examination, and that he wished to discuss problems relating to the trial with his client. The judge indicated his confidence that counsel would properly confine the discussion, but expressed some doubt that petitioner would be able to do so, saying: "I think he would understand it if I told him just not to talk to you; and I just think it is better that he not talk to you about anything." The judge suggested that counsel could have an opportunity immediately after the recess to discuss with his client matters other than the cross-examination, such as what witnesses were to be called the next day, and he indicated that he would grant a recess the next day so that counsel could consult with petitioner after petitioner's testimony ended. Counsel persisted in his objection, although he appropriately indicated that he would as in fact he did comply with the court's order.1

When court convened the next morning, petitioner's attorney asked and received permission to reopen his direct examination of petitioner. The cross-examination which followed was finished in the morning; the judge then called the luncheon recess. Petitioner whose testimony on redirect examination was yet to come—was permitted to confer with his attorney during the noon recess. The trial concluded the following day, and petitioner was convicted on all three counts; he was sentenced to concurrent three-year prison terms.

The Court of Appeals affirmed petitioner's conviction. United States v. Fink, 502 F.2d 1 (CA5 1974 On the point here at issue, the court held that petitioner's failure to claim any prejudice resulting from his inability to consult with counsel during one evening of the trial was fatal to his appeal. In so holding, the court relied on United States v. Leighton, 386 F.2d 822 (CA2 1967), cert. denied, 390 U.S. 1025, 88 S.Ct. 1412, 20 L.Ed.2d 282 (1968), dealing with a similar order applied to a noon recess, and rejected the Third Circuit's position that prejudice need not be shown, United States v. Venuto, 182 F.2d 519 (1950), in a case involving an overnight recess. The Court of Appeals also disposed of several other claims of error. We granted certiorari limited to petitioner's claim that the order forbidding consultation with his attorney overnight denied him the assistance of counsel in violation of the Sixth Amendment. 421 U.S. 929, 95 S.Ct. 1654, 44 L.Ed.2d 86.

Our cases have consistently recognized the important role the trial judge plays in the federal system of criminal justice. "(T)he judge is not a mere moderator, but is the governor of the trial for the purpose of assuring its proper conduct and of determining questions of law." Quercia v. United States, 289 U.S. 466, 469, 53 S.Ct. 698, 77 L.Ed. 1321, 1324 (1933). A criminal trial does not unfold like a play with actors following a script; there is no scenario and can be none. The trial judge must meet situations as they arise and to do this must have broad power to cope with the complexities and contingencies inherent in the adversary process. To this end, he may determine generally the order in which parties will adduce proof; his determination will be reviewed only for abuse of discretion. Goldsby v. United States, 160 U.S. 70, 74, 16 S.Ct. 216, 218, 40 L.Ed. 343, 345 (1895); United States v. Martinez-Villanueva, 463 F.2d 1336 (CA9 1972); Nelson v. United States, 415 F.2d 483, 487 (CA5 1969), cert. denied, 396 U.S. 1060, 90 S.Ct. 751, 24 L.Ed.2d 754 (1970). Within limits, the judge may control the scope of rebuttal testimony, United States v. Chrzanowski, 502 F.2d 573, 575-576 (CA3 1974); United States v. Perez, 491 F.2d 167, 173 (CA9), cert. denied Sub nom., Lombera v. United States, 419 U.S. 858, 95 S.Ct. 106, 42 L.Ed.2d 92 (1974); may refuse to allow cumulative, repetitive, or irrelevant testimony, Hamling v. United States, 418 U.S. 87, 127, 94 S.Ct. 2887, 2912, 41 L.Ed.2d 590, 626 (1974); County of Macon v. Shores, 97 U.S. 272, 24 L.Ed. 889 (1877); and may control the scope of examination of witnesses, United States v. Nobles, 422 U.S. 225, 231, 95 S.Ct. 2160, 2166, 45 L.Ed.2d 141, 149 (1975); Glasser v. United States, 315 U.S. 60, 83, 62 S.Ct. 457, 470, 86 L.Ed. 680, 706 (1942). If truth and fairness are not to be sacrificed, the judge must exert substantial control over the proceedings.

The judge's power to control the progress and, within the limits of the adversary system, the shape of the trial includes broad power to sequester witnesses before, during, and after their testimony. Holder v. United States, 150 U.S. 91, 92, 14 S.Ct. 10, 37 L.Ed. 1010 (1893); United States v. Robinson, 502 F.2d 894 (CA7 1974); United States v. Eastwood, 489 F.2d 818, 821 (CA5 1974). Wigmore notes that centuries ago, the practice of sequestration of witnesses "already had in English practice an independent and continuous existence, even in the time of those earlier modes of trial which preceded the jury and were a part of our inheritance of the common Germanic law." 6 J. Wigmore, Evidence § 1837, p. 348 (3d ed., 1940). The aim of imposing "the rule on witnesses," as the practice of sequestering witnesses is sometimes called, is twofold. It exercises a restraint on witnesses "tailoring" their testimony to that of earlier witnesses; and it aids in detecting testimony that is less than candid. See Wigmore, Supra, § 1838; F. Wharton, Criminal Evidence § 405 (C. Torcia ed. 1972). Sequestering a witness over a recess called before testimony is completed serves a third purpose as well preventing improper attempts to influence the testimony in light of the testimony already given.

The trial judge here sequestered all witnesses for both prosecution and defense and before each recess instructed the testifying witness not to discuss his testimony with anyone. Applied to nonparty witnesses who were present to give evidence, the orders were within sound judicial discretion and are not challenged here.

But the petitioner was not simply a witness; he was also the defendant. A sequestration order affects a defendant in quite a different way from the way it affects a nonparty witness who presumably has no stake in the outcome of the trial. A nonparty witness ordinarily has little, other than his own testimony, to discuss with trial counsel; a defendant in a criminal case must often consult with his attorney during the trial. Moreover, "the rule" accomplishes less when it is applied to the defendant rather than a nonparty witness, because the defendant as a matter of right can be and usually is present for all testimony and has the opportunity to discuss his testimony with his attorney up to the time he takes the witness stand.

The recess at issue was only one of many called during a trial that continued over 10 calendar days. But it was an overnight recess, 17 hours long. It is common practice during such recesses for an accused and counsel to discuss the events of the day's trial. Such recesses are often times of intensive work, with tactical decisions to be made and strategies to be reviewed. The lawyer may need to obtain from his client information made relevant by the day's testimony, or he may need to pursue inquiry along lines not fully explored earlier. At the very least, the overnight recess during trial gives the defendant a chance to discuss with counsel the significance of the day's events. Our cases recognize that the role of counsel is important precisely because ordinarily a defendant is ill-equipped to understand and deal with the trial process without a lawyer's guidance.

"The right to be heard would be, in many cases, of little avail if it did not comprehend the right to be heard by counsel. . . . (A defendant) is unfamiliar with the rules of evidence. . . .He lacks both the skill and knowledge adequately to prepare his defense, even though he (may) have a perfect one. He requires the guiding hand of counsel at every step in the proceedings against him." Powell v. Alabama, 287 U.S. 45, 68-69, 53 S.Ct. 55, 64, 77 L.Ed. 158, 170 (1932).

See also Argersinger v. Hamlin, 407 U.S. 25, 31-36, 92 S.Ct. 2006, 2009-2012, 32 L.Ed.2d 530, 535-537 (1972); Gideon v. Wainwright, 372 U.S. 335, 343-345, 83 S.Ct. 792, 796, 9 L.Ed.2d 799, 804 (1963). Other courts have concluded that an order preventing a defendant from consulting his attorney during an overnight recess infringes upon this substantial right. See United States v. Venuto, 182 F.2d 519 (CA3 1950); People v. Noble, 42 Ill.2d 425, 248 N.E.2d 96 (1969); Commonwealth v. Werner, 206 Pa.Super. 498, 214 A.2d 276 (1965). But see People v. Prevost, 219 Mich. 233, 189 N.W. 92 (1922).2

There are other ways to deal with the problem of possible improper influence on testimony or "coaching" of a witness short of putting a barrier between client and counsel for so long a period as 17 hours. The opposing counsel in the adversary system is not without weapons to cope with "coached" witnesses. A prosecutor may cross-examine a defendant as to the extent of any "coaching" during a recess, subject, of course, to the control of the court. Skillful cross-examination could develop a record which the prosecutor in closing argument might well exploit by raising questions as to the defendant's credibility, if it developed that defense counsel had in fact coached the witness as to how to respond on the remaining direct examination and on cross-examination. In addition the trial judge, if he doubts that defense counsel will observe the ethical limits on guiding witnesses,3 may direct that the examination of the witness continue without interruption until completed. the judge considers the risk high he may arrange the sequence of testimony so that direct- and cross-examination of a witness will be completed without interruption. That this would not be feasible in some cases due to the length of direct- and cross-examination does not alter the availability, in most cases, of a solution that does not cut off communication for so long a period as presented by this record. Inconvenience to the parties, witnesses, counsel, and court personnel may occasionally result if a luncheon or other recess is postponed or if a court continues in session several hours beyond the normal adjournment hour. In this day of crowded dockets, courts must frequently sit through and beyond normal recess; convenience occasionally must yield to concern for the integrity of the trial itself.

There are a variety of ways to further the purpose served by sequestration without placing a sustained barrier to communication between a defendant and his lawyer. To the extent that conflict remains between the defendant's right to consult with his attorney during a long overnight recess in the trial, and the prosecutor's desire to cross-examine the defendant without the intervention of counsel, with the risk of improper "coaching," the conflict must, under the Sixth Amendment, be resolved in favor of the right to the assistance and guidance of counsel. Brooks v. Tennessee, 406 U.S. 605, 92 S.Ct. 1891, 32 L.Ed.2d 358 (1972).

The challenged order prevented petitioner from consulting his attorney during a 17-hour overnight recess, when an accused would normally confer with counsel. We need not reach, and we do not deal with limitations imposed in other circumstances. We hold that an order preventing petitioner from consulting his counsel "about anything" during a 17-hour overnight recess between his direct- and cross-examination impinged upon his right to the assistance of counsel guaranteed by the Sixth Amendment.

Accordingly, the judgment of the Court of Appeals is reversed, and the case is remanded to the Court of Appeals, with directions that it be remanded to the District Court for proceedings consistent with this opinion.

Reversed and remanded.

Mr. Justice STEVENS took no part in the consideration or decision of this case.

Mr. Justice MARSHALL, with whom Mr. Justice BRENNAN joins, concurring.

I join in most of the Court's opinion, and I agree with its conclusion that an order preventing a defendant from consulting with his attorney during an overnight recess violates the defendant's Sixth Amendment right to counsel.

The Court notes that this case does not involve an order barring communication between defendant and counsel during a "brief routine recess during the trial day."1 Ante, at 89 n. 2. That is, of course, true. I would add, however, that I do not understand the Court's observation as suggesting that as a general rule no constitutional infirmity would inhere in an order barring communication between a defendant and his attorney during a "brief routine recess." In my view, the general principles adopted by the Court today are fully applicable to the analysis of Any order barring communication between a defendant and his attorney, at least where that communication would not interfere with the orderly and expeditious progress of the trial.

Thus, as the Court holds, a defendant who claims that an order prohibiting communication with his lawyer impinges upon his Sixth Amendment right to counsel need not make a preliminary showing of prejudice. Such an order is inherently suspect, and requires initial justification by the Government.

The only justification expressly considered by the Court in its opinion is the desire to avoid the risk of unethical counseling by an attorney.2 The Court holds that the fear of unethical conduct is not a sufficient ground for an order barring overnight communication between a defendant and his attorney, and the same would hold true absent the most unusual circumstances, I take it, for an order barring consultation between a defendant and his attorney at Any time before or during the trial.3 If our adversary system is to function according to design, we must assume that an attorney will observe his responsibilities to the legal system, as well as to his client. I find it difficult to conceive of any circumstances that would justify a court's limiting the attorney's opportunity to serve his client because of fear that he may disserve the system by violating accepted ethical standards. If any order barring communication between a defendant and his attorney is to survive constitutional inquiry, it must be for some reason other than a fear of unethical conduct.