A jury convicted Samuel Cerro of five counts of conspiracy to distribute cocaine and three counts of filing false income tax returns. The judge gave him concurrent 15-year sentences on the first three conspiracy counts and consecutive 15-year sentences on the fourth and fifth conspiracy counts, for a total of 45 years. (Sentences of 3 years on each of the tax counts were made concurrent with the conspiracy sentences.) Cerro had also been charged with being a drug “kingpin,” see 21 U.S.C. § 848, a charge that allows the most severe punishment possible under current federal law — life in prison without possibility of parole, see 21 U.S.C. §§ 848(a), (c), but this charge was dropped before trial on the authority of a dictum in
United States v. Jefferson,
The principal issue raised by Cerro’s appeal is whether the five conspiracies were indeed separate or were instead aspects of a single conspiracy; if the latter, the maximum sentence (apart from the tax counts) is 15 years and Cerro must be resentenced. Each of the alleged conspiracies was between Cerro and one other person, to whom Cerro consigned (“fronted”) up to one ounce of cocaine each week for resale to users of cocaine. Each dealer would remit all or part of his retail sales revenues to Cerro, either retaining some of the revenues as compensation for his services or retaining some of the cocaine in lieu of money compensation.
The five dealers were the principal witnesses against Cerro, testifying under grants of immunity. In Count I the dealer was Amato, and the evidence showed that the conspiracy ran from April 1980 to December 1980. The dealer and dates for the other conspiracies were as follows. Count II: Corti, summer or fall of 1978 to November 1980; Count III: Gaulke, March 1977 to the spring of 1979; Count IV: Schnidt, August 31, 1977 to December 8, 1980; Count V: Phillips, fall of 1979 to spring of 1981. Why the district judge imposed concurrent sentences for the first three conspiracies and consecutive ones for the last two is unclear. The fifth conspiracy did end later than the others, but the fourth (August 1977 to December 1980) fell within the overall span of the first three (March 1977 to December 1980).
There was no evidence that any of the dealers knew that Cerro was selling cocaine through other dealers, beyond what might be inferred from the nature and timing of the conspiracies and the facts that all the transactions took place in Madison, Wisconsin, that Amato and Gaulke were brothers-in-law, that Corti “fronted” cocaine to Amato as well as selling cocaine at retail for Cerro, and that Phillips knew that Corti sold cocaine, though there is no indication that he knew that Cerro was Corti’s supplier.
More often it is the government that is arguing for a single overarching conspiracy and the defendant for multiple conspiracies, the most recent examples in this court being
United States v. Andrus,
By a fluke, none of the disadvantages
of
multiple conspiracies to the government is present here (there is no misjoinder problem because there is only one defendant, so that Rule 8(a), which is more liberal than 8(b), see
United States v. Velasquez, supra,
A conspiracy is an agreement; and to be a party to an agreement you must know something of its general scope and objective though not necessarily its details. See
id.
at 1351;
Blumenthal v. United States,
The cases sometimes say must know
{Borelli, Elam,
many others), less frequently must have reason to know (e.g., Barnes). Taken literally the latter formulation would imply something very curious indeed, that a conviction can be upheld without proof beyond a reasonable doubt of an element of the crime (knowledge of the conspiracy). But it should not be taken literally. Although usually in the law to say that someone has “reason to know” something means that he would be negligent in not knowing it, in the present context it means only that knowledge can be inferred from circumstantial evidence. If the facts indicate that the defendant must have known something (the formulation in
Borelli),
then a jury may be able to find beyond a reasonable doubt that he did know it, especially since the requirement of knowledge is satisfied by proof that the defendant willfully shut his eyes for fear of what he might see if he opened them,
United States v. Josefik,
A jury could have found that Cerro’s dealers knew there were other dealers if for example Cerro had told the dealers this, if other dealers had told them, if they had observed cocaine dealings between Cerro and other dealers, or if they had seen Cerro with a quantity of cocaine too large to be distributed through one dealer. See, e.g.,
Blumenthal v. United States, supra,
The failure to prove a single conspiracy is not surprising. It was no part of the government’s purpose to show an overarching conspiracy — quite the contrary — or to show that the prosecution witnesses were members of such a conspiracy. And while Cerro might have wanted to establish a single conspiracy in order to put a cap on his sentence if he was convicted, he would not have improved his chances for acquittal by exploring the extent of the witnesses’ knowledge of each other’s dealings on his behalf. Testimony of their knowledge would have strengthened the case against him; testimony of their lack of knowledge would not have weakened it.
But lack of proof that the dealers knew about each other need not be decisive on the question whether Cerro could be punished for multiple conspiracies. It is never right to try to answer a legal question, such as (in this case) whether there was one conspiracy or five conspiracies, without considering the purpose of the question. The purpose here is to decide whether Cer-ro was given an illegal sentence. For other purposes it would be clear that there were multiple conspiracies. It would be clear for example if any of the dealers had been charged with participating in an overarching conspiracy and the issue was whether the dealer could be convicted; lack of proof of a dealer’s knowledge of a conspiracy broader than his own dealings with Cerro would doom any attempt to make such a charge stick.
If on the other hand Cerro had been charged with being the hub of a single conspiracy embracing all five dealers, proof of the dealers’ knowledge, though no doubt easy to come by if the government had wanted to explore that knowledge, might conceivably not have been necessary. Suppose, as has become familiar from the literature on espionage, revolution, and terrorism, that the leading members of a clandestine organization seek to minimize the chances of detection by adopting a system of “cut-outs” under which subordinate members know nothing about their superiors, their coordinate members, conceivably even the objects of the organization. See, e.g., Copeland, Without Cloak or Dagger: The Truth About the New Espionage 111-12, 140 (1974); Seth, Anatomy of Spying 97 (1963). It might be possible to argue that the leaders’ ability to conduct their operations through completely insulated cells, thereby making those operations more rather than less effective, should not protect the leaders from charges of participation in one large conspiracy rather than a series of petty two-man conspiracies, with all the obstacles to effective prosecution in the run of cases that multiple-conspiracy charges create; that the “hub” of an illegal enterprise can be guilty of conspiracy even if the “spokes” do not have a common rim. Otherwise there is the paradox that “a central figure will be guilty of one conspiracy or of many, depending entirely upon whether he informed each individual with whom he plotted of the others’ existence.” *913 Developments in the Law, Criminal Conspiracy, 72 Harv.L.Rev. 920, 928 (1959).
Whether the objection that a conspiracy of many requires a multiplicity of knowing conspirators could be surmounted is fortunately not an issue we need decide in this case. Maybe it will never have to be decided. In the type of case we have put each spoke is bound to know, in fact, that he is “participating in a collective venture” of some sort,
United States v. Martino,
In this case, where the only issue is length of sentence and no one suggests that the defendant was attempting to minimize his fellow conspirators’ knowledge of the larger conspiracy, the argument against finding multiple conspiracies is compelling. The government cannot, just by choosing to prove less than it could easily have proved by asking its own witnesses another question — namely, whether each of the dealers realized he was not alone — get a defendant punished more severely; cannot, simply by not proving a single conspiracy, obtain punishment more severe than if it had proved one; cannot shift, to a defendant fearful of more severe punishment, the burden of proving how much his coconspirators knew about the conspiracy. The balance of advantages in a conspiracy case is adequately in the prosecutor’s favor without his being allowed to gain a sentencing bonus by atomizing a single venture. Maybe for purposes of trial the government can charge as many conspiracies as it wants unless the effect is to confuse the jury. But we do not think the government can get the judge to pile on consecutive sentences by arbitrarily, as in this case, declining to present minimum evidence of what is pretty apparent without evidence, that there really was one conspiracy.
The issue has arisen more commonly when the government, rather than charging multiple conspiracies in the same case (for, as we have said, the government’s interests are ordinarily best served by charging a single overarching conspiracy), reindicts a defendant acquitted (or convicted) on another conspiracy charge, and the defendant argues that the conspiracies are one and the same for purposes of double jeopardy. Courts in such cases do not ask just whether the evidence required to establish the defendant’s guilt is the same in both cases; that would encourage the prosecution to withhold some of its evidence in the first case. They also ask whether the “conspiracy has been subdivided arbitrarily, resulting in multiple indictments for a single illegal agreement.”
United States v. Castro,
Contrary to its usual position in conspiracy cases, the government argues, how
*914
ever, that it could not have charged a single conspiracy, because the dealings between Cerro and each dealer were not “mutually dependent.” Many cases do say that mutual dependence must be shown for a course of dealings to be a single conspiracy. See, e.g.,
United States v. Percival,
The expression “mutual dependence” can be taken literally only in cases (and not all of them, either) where the conspirators are different links in the chain of distribution. If the conspiracy is to distribute imported drugs and the sole importer defects, an essential link has been severed. But when the conspirators (all but one) sell in parallel, each is a strand rather than a link, and normally an inessential one; yet conspiracies of this sort are prosecuted all the time, and successfully, too. You can be part of a common enterprise without being indispensable to that enterprise; and a common enterprise for illegal ends is a conspiracy whose inessential as well as essential members are conspirators.
“Mutual support” would be a more accurate description of the cases, which require at most that the various arrangements and transactions alleged to constitute or manifest a single conspiracy contribute to the success of the overall undertaking and in that sense reinforce each other. At any rate, by choosing not to inquire into the dealers’ knowledge of Cerro’s operation, the government is barred from obtaining a sentencing advantage, since as we have said the facts show that Cerro was the hub of a conspiracy the “spokes” of which probably knew of each other’s existence, and which was no more effective or dangerous a conspiracy if, contrary to all the probabilities, they in fact were in the dark and thought, each one, that he was Cerro’s only dealer.
The only other question that requires discussion (Cerro’s other grounds of appeal being plainly without merit) is whether his conviction should be reversed because the district court improperly curtailed his efforts to impeach the credibility of the dealers, the principal witnesses against him. The pretrial order in this case, which apparently is used routinely by this district judge in criminal cases, requires written notice before the final pretrial conference if either counsel intends to try to present at trial evidence of, among other things, “prior similar acts or any person ([Fed.R.Evid.] 404(b)).” Cerro’s counsel did not object to the order and did not give the required notice, and at trial the judge forbade him to present some of the evidence regarding the prior crimes of the witnesses with which he hoped to impeach them. The two most important items of evidence that were excluded were that witness Gaulke’s insurance-brokerage license had been revoked for fraud and that witness Corti was an extortionist.
Although the district judge must know better than we what his pretrial order means, we find it very hard to understand how it could be read to require that defense counsel give the prosecution writ *915 ten notice of the evidence with which he hopes to undermine the jury’s belief in the truth of the testimony of the prosecution witnesses (and thus Cerro’s counsel cannot be faulted for having failed to object to the order when it was entered). Rule 404(b), which provides that evidence of other crimes, wrongs, or acts illuminating a person’s character is not admissible in order to prove that he acted in conformity with that character (but allows it to be admitted for other purposes), applies to evidence in chief, not to impeachment evidence. This is apparent from a comparison with Rules 608 and 609, which deal specifically with using evidence of character and of prior crimes to impeach witnesses. See also the Advisory Committee’s Note to Rule 608(a).
Whatever the pretrial order means, there is a serious question whether a district judge is empowered to require discovery of impeachment evidence. Pretrial discovery of federal criminal defendants is regulated in detail by Rules 12.1, 12.2, and 16 of the Federal Rules of Criminal Procedure, and nothing in any of them suggests that impeachment evidence is discoverable. Rule 16(b)(1)(A) limits compelled disclosure of defense documents to those “which the defendant intends to introduce as evidence in chief at the trial.” Rule 16(d), on which the government relies here, regulates the manner rather than objects of discovery from a criminal defendant and is thus irrelevant to our issue. Whether the provision for pretrial conferences made by Rule 17.1 is intended to override the limitation in Rule 16(b)(1)(A) is most doubtful. Nothing in the language or history of the rule suggests that it is, an omission not surprising when we consider that a defendant’s interest in being able to conduct a vigorous and effective cross-examination — an interest central to the right of a criminal defendant under the Sixth Amendment “to be confronted with the witnesses against him,” see, e.g.,
Davis v. Alaska,
But any error here was harmless beyond a reasonable doubt. Keeping the revocation of Gaulke’s broker’s license from the jury could do little harm to the defendant. Given Gaulke’s own testimony that he had stolen funds from his employer to pay for cocaine that he bought from Cerro, evidence that his insurance broker’s license had been revoked would have been anticlimactic and its exclusion was surely harmless. And similarly with Corti. Evidence that he was an-extortionist was excluded, it is true, but Corti admitted having committed perjury (though he said it had been done under duress), and perjury is more relevant to credibility than extortion would be. And remember that the whole premise of Gaulke’s and Corti’s testimony, as of the testimony of the other three dealers, was that they had sold cocaine illegally. Thus it is not as if the jury could have thought that Gaulke and Corti were anything but what they were: crooks singing for their freedom. Finally, the evidence of Cerro’s guilt would have been overwhelming even if Gaulke and Corti had been thoroughly discredited by a mountain of evidence of their prior crimes — especially once the three conspiracies are recharacterized as one, as we have held they must be.
It is always perilous to speculate on what the effect of evidence improperly admitted was on a jury, or what the effect of evidence improperly excluded would have been. See Teitelbaum, Sutton-Barbere & Johnson,
Evaluating the Prejudicial Effect of Evidence: Can Judges Identify the Impact of Improper Evidence
*916
on Juries?,
1983 Wis.L.Rev. 1147. The lay mind evaluates evidence differently from the legal mind, and while many appellate judges have substantial experience with juries and perhaps great insight into the thinking process of juries, others do not. This is a reason to be wary about invoking the doctrine of harmless error (on which see, e.g.,
United States v. Hasting,
Most cases of harmless error involve the erroneous admission of evidence favorable to the prosecution. As a practical matter, if the evidence of guilt that was neither erroneously admitted nor tainted by the erroneously admitted evidence is overpowering, and the tainted evidence neither probative nor inflammatory (inflammatory evidence might overbear the judgment of a lay trier of fact), so that the appellate court can safely conclude that the likelihood that the defendant would have been acquitted is very small — too small to warrant the delays and other costs entailed by ordering a new trial — the error will be pronounced harmless (harmless beyond a reasonable doubt, if the appellate court is strongly convinced of its conclusion).
Despite some contrary language in
Davis v. Alaska, supra,
But we are far from that extreme point in this case. Cerro’s defense was impeded, probably improperly, but the impediment was a minor one; the error in keeping from the jury impeachment evidence of a marginal and cumulative nature must be deemed harmless beyond a reasonable doubt in a ease such as this where the evidence of guilt was overwhelming and the defendant was allowed to put on a defense, if not quite so complete a defense as he might reasonably have desired. Cases in which error in the curtailment of a criminal defendant’s right of effective cross-examination was found not harmless, such as
Hoover v. Maryland,
So Cerro’s convictions must stand, along with the sentences for the tax offenses. But the case must be returned for resen- *917 tencing on the conspiracy counts in accord-anee with our conclusion that the defendant cannot be given consecutive sentences on those counts.
Affirmed in Part, Vacated in Part, and Remanded with Directions.
