A jury convicted appellant Marcus T. Powell of two counts of distributing crack cocaine, and the district court sentenced him to 420 months’ imprisonment for those offenses. Powell now claims that evidence offered against him regarding his other drug dealing activity was inadmissible, that the jury was allowed to hear testimony regarding his likely sentence if convicted, and that the court should not have instructed the jury on an aiding-and-abetting theory of criminal liability. Powell also asks us to reconsider circuit precedent barring retroactive application of the Fair Sentencing Act of 2010. We affirm.
I. The Facts
On January 17, 2008, law enforcement officials directed confidential informant Darnell Yarbrough to contact Powell and arrange a purchase of crack cocaine. After calling Powell, Yarbrough proceeded to a residence in East St. Louis, Illinois, where he used money provided by law enforcement to purchase a quantity of crack cocaine. On January 30, Yarbrough again contacted Powell and arranged a second purchase of crack cocaine. Yarbrough then returned to the same residence in East St. Louis, where he again used money provided by law enforcement to purchase a quantity of crack cocaine. After each controlled buy, Yarbrough turned over the cocaine he purchased to law enforcement officers. Following these two controlled buys, Powell was arrested and charged with two counts of intentionally distributing five grams or more of crack cocaine in violation of 21 U.S.C. § 841(a)(1) & (b)(1)(B).
At trial, the prosecution’s star witness was Yarbrough, who testified that he had purchased cocaine from Powell on January 17 and January 30, 2008. During Yarbrough’s testimony, the prosecution played for the jury the recordings of the January 17 telephone conversations between Yarbrough and Powell arranging the initial controlled buy. The prosecution also played for the jury video recordings Yarbrough secretly made when he purchased the cocaine from Powell. Those video recordings show that a number of individuals were inside the residence at the time Yarbrough made the controlled buys.
The evidence at trial also included recordings of telephone calls Powell made from the Alton City Jail after his arrest. In those calls, Powell — apparently unaware that it is common practice to record prisoners’ calls — admitted his guilt of the crimes with which he had been charged. In one call, Powell admitted that if he had not been arrested, he would still be on the street selling drugs. In another, Powell complained that Yarbrough had underpaid him for the January 17 sale, and he speculated that Yarbrough had recorded the drug sales using a camera hidden in a necklace. In yet another, Powell explained that he would rather be considered a drug smuggler than a drug dealer, and he bragged that “as much shit as I be *706 doing ... they ain’t got me on [anything] but two ... sales.”
The jury convicted Powell on both counts of the indictment. At sentencing, the district judge characterized Powell as the most dangerous drug dealer he had ever encountered, an individual “devoid of a conscience” who manipulated the court system “in order to buy more time to intimidate witnesses from testifying.” The district court also took note of the extraordinary measures necessary during trial and at sentencing to maintain order and to ensure the safety of the witnesses against Powell. Based on all of this, as well as Powell’s leadership role in a large-scale drug distribution network, the court deemed it necessary that Powell “be incarcerated until [he is] criminally impotent” and sentenced him to 420 months’ imprisonment, a time the court estimated to be just short of the likely remainder of Powell’s natural life. This appeal followed.
II. Cumulative Error
Powell’s primary argument on appeal is that a number of evidentiary errors resulted, cumulatively, in the denial of his constitutional right to a fair trial. To succeed on this theory, Powell must show (1) that multiple errors occurred at trial; and (2) those errors, in the context of the entire trial, were so severe as to have rendered his trial fundamentally unfair.
Alvarez v. Boyd,
To show the multiple errors necessary under cumulative error analysis, Powell asserts that Yarbrough’s statements about Powell’s other drug dealing activity were all inadmissible under Federal Rule of Evidence 404(b). At trial, Yarbrough testified that Powell had “fronted” him some cocaine in May 2007 because Yarbrough was low on cash at the time. Yarbrough also testified that, in March 2008, after the charged sales of cocaine, Powell was going out of town to pick up some cocaine and offered Yarbrough “extra cocaine for [his] money” if he paid in advance. Lastly, Yarbrough testified that he had called Powell on July 16, 2008, to discuss a possible purchase of crack cocaine. This brief telephone call was recorded, and the recording was played for the jury. The district court overruled Powell’s objections to all of this testimony, instructing the jury that it could consider Yarbrough’s statements only as evidence of Powell’s intent.
The district court erred by admitting this evidence of Powell’s other drug dealing activity as evidence of his intent to unlawfully distribute cocaine. Although Rule 404(b) generally allows evidence of other bad acts as proof of a defendant’s intent, such bad acts may be admitted as evidence of a defendant’s intent to distribute illegal narcotics only when that defendant has put his intent at issue. See
United States v. Hicks,
At the same time, such other bad acts’ potential for unfair prejudice is substantial. The prior acts used to show intent to distribute narcotics are often prior drug dealings, and it can be easy for jurors to slide across Rule 404(b)’s slippery boundary between proper consideration of intent and improper consideration of propensity. Because those prior acts have minimal probative value in the absence of a challenge to the evidence of intent, and because they are particularly susceptible to misuse, they are generally not admissible to show an intent to distribute drugs on the familiar ground that evidence is inadmissible if its potential for unfair prejudice significantly outweighs its probative value. Only if the defendant puts his intent at issue, then, is it possible to present Rule 404(b) evidence regarding such intent, shifting the probative/prejudicial balance in favor of admission. See
Hicks,
Although Powell has managed to show that multiple errors occurred at his trial, those errors were harmless beyond any reasonable doubt. The evidence the government brought to bear against Powell — the recordings of the telephone calls arranging the initial purchase of cocaine, Yarbrough’s testimony, the video recordings of each sale, and the recordings of Powell’s telephone calls from jail — was overwhelming. The district court observed at sentencing that the evidence was so strong that “only 12 people unfit to serve as jurors could have found [Powell] not guilty.” In light of the quantity and quality of evidence of Powell’s guilt adduced at trial, we are confident that the relatively minor errors of which Powell complains did not have any effect on the jury’s verdict. 3
*708 III. Aiding and Abetting Instruction
Over Powell’s objection, the district court instructed the jury that anyone who aids in the commission of an offense may be found guilty of that offense if he knowingly associates with the criminal activity, participates in the activity, and tries to make it succeed. Powell argues that this instruction was erroneous because it was not supported by the evidence at trial and because the prosecution first requested this instruction only after two of its witnesses had already testified and been cross-examined.
We review the district court’s decision to give an instruction on aiding and abetting, like all jury instructions, for an abuse of discretion, reviewing any underlying issues of law de novo.
United States v. Tavarez,
The instruction on aiding and abetting was warranted so long as some evidence indicated that Powell associated himself with the drug sale, participated voluntarily in it, and tried to make it succeed. See
United States v. Aldaco,
Regarding unfair surprise, Powell admits that his trial strategy was “to suggest that [he] was not guilty because he was not a principal in the drug sales charged.” Having adopted this strategy, Powell cannot claim that he was unfairly surprised by the government’s request for an instruction on aiding and abetting. See
United States v. Smith,
*709 IV. Motion for Mistrial
Powell further contends that the district court should have granted his request for a mistrial. In one of the recorded telephone calls, Powell explained that the two cocaine sales with which he was charged were “petty,” but that if he had been caught later, the prosecution “woulda been trying to bury” him for all the drug sales he would have made during that time. After this recording was played for the jury, a prosecution witness explained that Powell was saying that, if the government “had continued the investigation for eight years” longer, it would have had “a lot more crack cocaine” and Powell “would be looking at a substantial amount of time.” Powell immediately moved for a mistrial, claiming that this testimony implied that “he is not looking at all that much time if [found] guilty.” Although the district court agreed with Powell that “any indication as to what the potential sentence in this case would be ... is improper,” it denied Powell’s motion on the grounds that the witness’s statement was “a fair comment on what [Powell] had said and [a] fair interpretation.” Instead, the district court instructed the jury that Powell’s potential prison sentence was irrelevant and could not be taken into consideration when reaching its verdict.
We review the district court’s denial of Powell’s motion for a mistrial for an abuse of discretion.
United States v. Collins,
V. Retroactive Application of the Fair Sentencing Act
Finally, Powell argues that his sentence was imposed in violation of the Fair Sentencing Act of 2010, which “amended the Controlled Substances Act and Controlled Substances Import and Export Act by resetting the drug quantities required to trigger mandatory minimum sentences.”
United States v. Bell,
*710
In response, the government asks us to limit our review to plain error because “Powell did not raise this issue [before the district court] even though the legislation that eventually became the Fair Sentencing Act ... was introduced on October 15, 2009, before Powell’s sentencing.” We decline this invitation. Although we will review arguments not made to the district court for plain error even if those arguments were rendered futile by precedent in existence at the time of trial, see,
e.g., United States v. Paladino,
Turning to the merits of Powell’s argument, we have already held that the Fair Sentencing Act does not apply retroactively to sentences imposed before that Act was signed into law.
Bell,
Defendant Powell’s convictions and sentence are Affirmed.
Notes
. This is in contrast with, for example, homicide crimes. When one person kills another, a wide variety of mental states — intent, recklessness, negligence — may be consistent with that act, making specific evidence beyond that of the act itself often necessary to show the killer’s precise mental state.
. Two of the other acts at issue here occurred
after
Powell’s charged drug sales. While Rule 404(b) does not restrict the evidence concerning other acts to events that took place before the alleged crime, the probative value of post-offense conduct may often be somewhat limited, depending on the circumstances. See
United States v. Anifowoshe,
. Powell also complains that one government witness incorrectly referred to a man named Ricardo Mason as Powell’s “co-defendant,” and that the government presented testimony that Yarbrough's actions as a confidential informant had led Mason to plead guilty to drug charges. Even if we assumed that this testimony was in error, that would not alter our harmless error analysis. For one thing, Powell immediately objected to this testimony, and the district court sustained both objections. Regarding Mason's guilty plea, the court cured any error when it instructed the
jury to
disregard Yarbrough’s statement and explained that Mason’s guilty plea “has nothing to do with this case.” See,
e.g., United States v. Fulk,
. We question whether it is ever possible for a defendant to be unfairly surprised by an aiding and abetting instruction. Neither Powell nor we have found any published cases finding such unfair surprise. (The one case Powell cites on the issue is entirely off point.) Aiding and abetting is not a separate crime but a fundamental principle of criminal liabil *709 ity, and every competent member of the defense bar should be aware of it.
. Two judges dissented from this court’s decision not to rehear
Fisher
en banc, arguing that the Fair Sentencing Act should apply to defendants who, unlike Powell, were sentenced
after
that Act's passage.
United States v. Fisher,
