                                In the

    United States Court of Appeals
                 For the Seventh Circuit

No. 12-1104

UNITED STATES OF AMERICA,
                                                     Plaintiff-Appellee,

                                   v.

NICOLAS GOMEZ,
                                                 Defendant-Appellant.


            Appeal from the United States District Court
        for the Northern District of Illinois, Eastern Division.
            No. 10 cr 1055-1 — William J. Hibbler, Judge.



  ARGUED SEPTEMBER 11, 2013 — DECIDED AUGUST 18, 2014



   Before WOOD, Chief Judge, and BAUER, POSNER, FLAUM,
EASTERBROOK, KANNE, ROVNER, WILLIAMS, SYKES, TINDER, and
HAMILTON, Circuit Judges.
    SYKES, Circuit Judge. Federal agents suspected Nicolas
Gomez of involvement in a cocaine-distribution ring operating
in Chicago and Milwaukee. A wiretap on the phones of Robert
Romero, a known Chicago supplier, revealed a reseller named
2                                                   No. 12-1104

“Guero” who lived in Milwaukee. The agents believed that
Gomez was Guero. When Romero and Guero scheduled a deal
for September 3, 2010, the agents followed Romero as he drove
from Chicago to Milwaukee and parked his car on a street near
Gomez’s house. The two men had a brief conversation next to
Romero’s car and then left the scene on foot. Later that day the
agents seized Romero’s car—still parked where he had left it—
and found a quarter kilogram of cocaine in the trunk. Gomez
was arrested and charged with conspiracy to distribute cocaine
and related crimes.
    At trial the government introduced more than 50 recorded
telephone calls between Romero and Guero detailing their
cocaine transactions in the months leading up to September 3.
The evidence tying the calls to Gomez’s residence was over-
whelming, so his defense was that Guero must have been
Victor Reyes, his brother-in-law who lived in the same house.
In response the government sought to introduce a small
quantity of cocaine found in Gomez’s bedroom at the time of
his arrest. Gomez objected, citing Rule 404(b)(1) of the Federal
Rules of Evidence, which prohibits the admission of evidence
of other crimes, wrongs, or acts for the purpose of showing a
person’s character or propensity to behave in a certain way. So-
called “other act evidence” is admissible for other purposes,
however, see FED. R. EVID. 404(b)(2), and here the district court
admitted the evidence for the purpose of proving Gomez’s
identity as Guero.
   Gomez was convicted on all counts. On appeal he primarily
challenged the district court’s decision to admit the other-act
evidence under Rule 404(b)(2). A divided panel affirmed. We
No. 12-1104                                                  3

reheard the case en banc to clarify the framework for admitting
other-act evidence. We now conclude that our circuit’s four-
part test should be replaced by an approach that more closely
tracks the Federal Rules of Evidence. Applying a rules-based
framework here, we hold that the cocaine found in Gomez’s
bedroom should not have been admitted, but the error was
harmless, so we affirm the judgment.


                       I. Background
    In 2010 federal agents were investigating Romero, a
Chicago-based cocaine supplier. A wiretap on his phones
revealed that he was regularly conducting business with a
reseller in Milwaukee, a man he called “Guero” or “Guerito.”
The cell phones Guero used were registered to a residence at
2522 West Mineral Street in Milwaukee where Gomez and his
brother-in-law Reyes lived. (Other people lived in the house
too, although the record doesn’t identify them.) When Romero
and Guero arranged a cocaine sale over the phone, GPS data
tracked Romero driving from Chicago to an alley behind
Gomez’s house on Mineral Street. When several months of
wiretap evidence established this transactional pattern, the
only thing left was to catch the conspirators in the act.
   The opportunity came on September 2, 2010, when Romero
and Guero discussed a sale for the following day. On Septem-
ber 3, DEA agents staked out Gomez’s house in Milwaukee,
and a separate group of FBI agents followed Romero. He left
Chicago in a white Mercedes, drove to Milwaukee, and parked
on a street within a block and a half of Gomez’s house. Both
4                                                  No. 12-1104

groups of agents watched and videorecorded a brief
interaction between Gomez and Romero standing next to the
parked Mercedes. After a short conversation, the two men
shook hands, then parted company and walked away in
opposite directions.
    Gomez’s route took him past the DEA agents, who stopped
him to confirm his identity. Pretending to be part of an antigun
task force, they patted him down and asked for his name,
address, and telephone number. The number Gomez gave was
the same number Guero used to arrange the sale that day. The
agents let him go and Gomez walked home.
   A few minutes later, FBI agents watched as Gomez drove
a green minivan down the street and picked up Romero. The
two men drove to Mercado El Rey, a nearby restaurant and
grocery store, where they met Reyes (Gomez’s brother-in-law
and housemate). An FBI agent followed them into the restau-
rant and photographed the meeting. Surveillance continued as
the three men left El Rey and went their separate ways.
   Reyes drove away in a tan Suburban and was stopped and
identified by a DEA agent. Gomez and Romero must’ve been
spooked because neither of them returned to the white
Mercedes—Romero took a taxi all the way back to Chicago.
Later that day the federal agents seized the abandoned
Mercedes. A search of the car at DEA headquarters revealed a
quarter kilogram of cocaine hidden in the trunk.
    That evening and the following morning, recorded phone
calls showed Romero and Guero frantically reviewing the
events of September 3. Guero told Romero that the Mercedes
No. 12-1104                                                    5

had been towed and that he was using a new cell phone. (The
number Gomez gave to DEA agents was deactivated that very
day.) When Romero asked Guero what had happened after the
“three of [them]” left El Rey, Guero responded that his brother-
in-law had been stopped by police while driving away from
El Rey—exactly what happened to Reyes. Romero then asked
Guero when he had been stopped and searched by police, and
Guero explained that he was stopped while walking—exactly
what happened to Gomez.
    On September 29—almost four weeks later—federal agents
arrested Gomez at his home. On the kitchen table were
Gomez’s wallet and the cell phone Guero had been using since
September 3. When agents searched Gomez’s bedroom, they
found a shoe box filled with documents addressed to Gomez,
including a phone bill for one of the three cell phones Guero
had used up until September 3. Although all three cell phones
were registered under Reyes’s name, records from the cellular-
service provider confirmed that the billing statements were
addressed to Gomez at 2522 West Mineral Street. Agents also
found a small quantity of cocaine in the pocket of a pair of
pants in Gomez’s bedroom.
    Gomez was brought directly to the FBI’s prisoner process-
ing center in Chicago where two agents interviewed him. They
played three of the recorded phone calls, including the one
describing the events of September 3. Gomez identified his
own voice as Guero on all three. He was thereafter charged
with conspiracy to possess cocaine with intent to distribute, see
21 U.S.C. § 846, and three counts of using a telephone to
facilitate a drug crime, see id. § 843(b).
6                                                         No. 12-1104

    At trial the government introduced more than 50 recorded
phone calls and testimony from various federal agents to
establish the facts we’ve just described. Gomez’s defense was
mistaken identity—he claimed that he was simply in the wrong
place at the wrong time. He also argued that the government
would never be able to show him in possession of cocaine. In
response prosecutors sought to introduce the small quantity of
cocaine found in Gomez’s bedroom at the time of his arrest.
Gomez objected on Rule 404(b)(1) grounds. The trial judge
initially denied the government’s request but ultimately
admitted the evidence to show Gomez’s identity as Guero.1 In
the end Gomez focused his defense on attempting to raise a
reasonable doubt about the government’s contention that he
was Guero, arguing that it was more likely that Reyes was
Romero’s coconspirator. He reminded the jurors that Reyes
lived at the same address and had also met with Romero on
September 3, and that the cell phones used in the conspiracy
were registered in Reyes’s name. The jury convicted Gomez on
all counts.
   On appeal Gomez primarily challenged the admission of
the other-act evidence—the cocaine found in his bedroom on
the day of his arrest—and also raised a sentencing issue. A
divided panel of this court affirmed, but the disagreement was
limited to the evidentiary question. United States v. Gomez,
712 F.3d 1146, 1159 (7th Cir. 2013); id. at 1159–63 (Hamilton, J.,


1
 The court also allowed the other-act evidence for the purpose of showing
Gomez’s knowledge and the absence of mistake. The government no longer
defends the admission of the evidence for these purposes, so we do not
address them here.
No. 12-1104                                                  7

dissenting). We vacated the panel opinion and granted
rehearing en banc on Gomez’s challenge to the admission of
the other-act evidence under Rule 404(b). We now reinstate the
panel opinion on the sentencing issue and address only the
Rule 404(b) question.


                        II. Discussion
A. The Admissibility of Other-Act Evidence
   Rule 404(b) prohibits the admission of evidence of other
crimes, wrongs, or acts for the purpose of proving a person’s
character or propensity to behave in a certain way, but permits
the use of this evidence for other purposes:
          (1) Prohibited Uses. Evidence of a crime,
       wrong, or other act is not admissible to prove a
       person’s character in order to show that on a
       particular occasion the person acted in accor-
       dance with the character.
           (2) Permitted Uses; … This evidence may be
       admissible for another purpose, such as proving
       motive, opportunity, intent, preparation, plan,
       knowledge, identity, absence of mistake, or lack
       of accident.
FED. R. EVID. 404(b).
  Our circuit has long used a four-part test to determine
when other-act evidence is admissible:
       To determine if such evidence is admissible, the
       district court must engage in a four-pronged
8                                                     No. 12-1104

       analysis and evaluate whether (1) the evidence is
       directed toward establishing a matter in issue
       other than the defendant’s propensity to commit
       the crime charged, (2) the evidence shows that
       the other act is similar enough and close enough
       in time to be relevant to the matter in issue,
       (3) the evidence is sufficient to support a jury
       finding that the defendant committed the similar
       act, and (4) the probative value of the evidence is
       not substantially outweighed by the danger of
       unfair prejudice.
United States v. Zapata, 871 F.2d 616, 620 (7th Cir. 1989) (citing
United States v. Shackleford, 738 F.2d 776, 779 (7th Cir. 1984) for
parts (1), (2), and (4) of the test and Huddleston v. United States,
485 U.S. 681 (1988), for part (3)).
    Multipart tests are commonplace in our law and can be
useful, but sometimes they stray or distract from the legal
principles they are designed to implement; over time misappli-
cation of the law can creep in. This is especially regrettable
when the law itself provides a clear roadmap for analysis, as
the Federal Rules of Evidence generally do. We have noted this
problem in the Rule 404(b) context before. Especially in drug
cases like this one, other-act evidence is too often admitted
almost automatically, without consideration of the “legitimacy
of the purpose for which the evidence is to be used and the
need for it.” United States v. Miller, 673 F.3d 688, 692 (7th Cir.
2012); see also United States v. Jones, 455 F.3d 800, 812 (7th Cir.
2006) (Easterbrook, J., concurring) (“Allowing a prosecutor
routinely to introduce drug convictions in the case in chief
No. 12-1104                                                      9

without demonstrating relevance to some concrete dispute
between the litigants creates needless risk that a conviction will
rest on the forbidden propensity inference.”). Moreover, as we
explain here, some aspects of our test lack an adequate basis in
the rules.
    Our four-part test for evaluating the admissibility of other-
act evidence has ceased to be useful. We now abandon it in
favor of a more straightforward rules-based approach. This
change is less a substantive modification than a shift in
paradigm that we hope will produce clarity and better practice
in applying the relevant rules of evidence.


   1. Rules 401 & 402 (Relevance) and 104 (Relevance Condi-
       tioned on a Fact)
    All evidentiary questions begin with Rule 402, which
contains the general principle that “[r]elevant evidence is
admissible” and “[i]rrelevant evidence is not.” Rule 401 defines
relevant evidence as that which is both probative (having “any
tendency to make a fact more or less probable than it would be
without the evidence”) and material (the fact must be “of
consequence in determining the action”).
    The second and third factors in our four-part test generally
correlate to the basic relevance inquiry under Rules 401 and
402, but the rules do not apply with the rote inflexibility that
the test implies. Step three of the test directs the district court
to evaluate whether the evidence of the proffered other act is
sufficient to support a jury finding that the defendant commit-
ted it. Step two asks if the other act is both recent and similar
10                                                           No. 12-1104

enough to the conduct charged in the case to be relevant (i.e.,
“of consequence in determining the action”). See Zapata,
871 F.2d at 620.
    Step three—the “sufficiency” inquiry—flows from
Rule 104(b), which addresses relevance conditioned on a fact:
“When the relevance of evidence depends on whether a fact
exists, proof must be introduced sufficient to support a finding
that the fact does exist.” FED. R. EVID. 104(b).2 In Huddleston v.
United States, the Supreme Court considered whether the
admission of other-act evidence requires a preliminary finding
by the court that the act has been proved by a preponderance
of the evidence. 485 U.S. at 682. The Court held that it does not.
Id. at 689. Relying on the default principle that relevant
evidence is admissible unless a rule specifies otherwise, the
Court concluded that nothing in the text or history of Rules 104
or 404(b) requires the judge to find that the proponent has
proved the other act before the evidence may be admitted. Id.
at 687–89. Although a preliminary finding by the judge is not
required as a condition of admissibility, the Court emphasized
that other-act evidence may not be admitted unless the
evidence is sufficient for the jury to find by a preponderance of
the evidence that the other act was committed. Id. at 689–90.
This requirement remains in full force as a condition of
relevance.



2
 The text of Rule 104(b) was slightly different at the time of Huddleston v.
United States, 485 U.S. 681 (1988), but the change to the current language
was intended to be purely stylistic, so we quote the current text. FED. R.
EVID. 104 advisory committee’s notes (2011 amendments).
No. 12-1104                                                    11

    Step two of the test, which requires an inquiry into the
similarity and timing of the other act, is loosely connected to
the basic principles of relevance found in Rules 401 and 402.
See United States v. Foster, 652 F.3d 776, 785–86 (7th Cir. 2011)
(explaining that “the comparison of [the defendant’s] prior acts
to the charged crimes” is “directed at establishing the rele-
vancy of the 404(b) evidence”) (citing United States v. Lloyd,
71 F.3d 1256, 1264–65 (7th Cir. 1995)). But the strength of this
inquiry varies depending on the particular theory of admissi-
bility. For example, one permissible purpose for the introduc-
tion of other-act evidence is to prove a defendant’s identity
through a “distinctive manner of operation, or modus operandi.”
United States v. Simpson, 479 F.3d 492, 497–98 (7th Cir. 2007),
abrogated in part on other grounds by United States v. Boone,
628 F.3d 927, 933 (7th Cir. 2010). A prior act will be relevant to
this purpose when it “‘bears a singular strong resemblance to
the pattern of the offense charged’ with the similarities
between the two crimes ‘sufficiently idiosyncratic to permit an
inference of pattern.’” Id. at 498 (quoting United States v.
Thomas, 321 F.3d 627, 634–35 (7th Cir. 2003)). Sometimes the
prior bad act may be too dissimilar to be relevant to show a
distinctive pattern, leaving only the forbidden propensity
inference. Id.
    On the other hand, the need to check for similarity and
recency may be substantially diminished or nonexistent
depending on the particular purpose for which the evidence is
offered. See United States v. Torres, 977 F.2d 321, 326 (7th Cir.
1992); United States v. Beasley, 809 F.2d 1273, 1277 (7th Cir.
1987). In some cases the relative similarity of the other act to
12                                                    No. 12-1104

the charged offense may be unimportant as a test of relevance.
See, e.g., Foster, 652 F.3d at 785–86 (holding that the similarity
of the other-act evidence to the charged offense was “of
exceedingly minimal significance” when evidence of a prior
check-cashing scheme was introduced to show a criminal
relationship between the defendant and his accomplice in an
armed bank robbery); United States v. Shriver, 842 F.2d 968, 974
(7th Cir. 1988) (same with respect to motive). Recognizing this,
we have repeatedly said that the “similarity” requirement for
admitting other-act evidence is not “unduly rigid,” Foster,
652 F.3d at 785, but instead is “loosely interpreted and ap-
plied,” United States v. Vargas, 552 F.3d 550, 555 (7th Cir. 2008).
    Our discussion thus far should illustrate the problem of
treating the “similarity” and “timing” factors as formal boxes
to check in the admissibility analysis. It’s far too tempting to
stop at superficial comparisons without meaningfully analyz-
ing how the similarity and recency of the prior bad act affect its
relevance in the unique circumstances of the case. And the
similarity and timing of the other act may not bear on the
relevance question at all. We think it best to return to a
framework that weighs the relevance of other-act evidence
directly.
   To restate the principle in positive terms: The extent to
which a proffered “other crime, wrong, or act” is close in time
and similar to the conduct at issue in the case may have a
bearing on its relevance, which is the starting point for all
evidence questions, but the importance of testing for similarity
and recency will depend on the specific purpose for which the
other-act evidence is offered. The proponent of the other-act
No. 12-1104                                                                  13

evidence should address its relevance directly, without the
straightjacket of an artificial checklist.


    2. Rule 404(b)
    Rule 404(b) excludes relevant evidence of other crimes,
wrongs, or acts if the purpose is to show a person’s propensity
to behave in a certain way, but other-act evidence may be
admitted for “another purpose” including, but not limited to,
“proving motive, opportunity, intent, preparation, plan,
knowledge, identity, absence of mistake, or lack of accident.”
FED. R. EVID. 404(b). The rule is straightforward enough, but
confusion arises because admissibility is keyed to the purpose
for which the evidence is offered, and other-act evidence is
usually capable of being used for multiple purposes, one of
which is propensity.3 See Beasley, 809 F.2d at 1279–80 (“Almost


3
 A common misconception about Rule 404(b) is that it establishes a rule of
exclusion subject to certain exceptions. That’s not quite right. The text of the
rule does not say that propensity evidence is inadmissible except when it is
used to prove motive, opportunity, intent, etc. Rather, it says that propen-
sity evidence—other-act evidence offered to prove a person’s character and
inviting an inference that he acted in conformity therewith—is categorically
inadmissible. FED. R. EVID. 404(b)(1). But the rule also acknowledges that
there may be “another” use for other-act evidence—i.e., a different, non-
propensity use. FED. R. EVID. 404(b)(2). So it’s technically incorrect to
characterize the purposes listed in subsection (2) as “exceptions” to the rule
of subsection (1). The Rules of Evidence do contain some true exceptions to
the rule against propensity evidence, but they’re found elsewhere—notably
in Rules 412 through 415, which are limited to sexual-assault cases. In
contrast, the purposes enumerated in subsection (2) of Rule 404(b) simply
                                                                 (continued...)
14                                                            No. 12-1104

any bad act evidence simultaneously condemns by besmirching
character and by showing one or more of ‘motive, opportunity,
intent, preparation, plan, knowledge, identity, or absence of
mistake or accident’ … .”). In the criminal context, and espe-
cially in drug cases, few defendants are new to criminal activity
and the range of possible defenses is fairly limited, so at least
three of the permitted purposes listed in the rule—knowledge,
intent, and identity—are routinely in play.
    Because other-act evidence can serve several purposes at
once, evidentiary disputes under Rule 404(b) often raise the
following question: Does a permissible ultimate purpose (say,
proof of the defendant’s knowledge or intent) cleanse an
impermissible subsidiary purpose (propensity)? On the surface
the rule seems to permit this. But if subsection (b)(2) of the rule
allows the admission of other bad acts whenever they can be
connected to the defendant’s knowledge, intent, or identity (or
some other plausible non-propensity purpose), then the bar
against propensity evidence would be virtually meaningless.
We have made this point before. See, e.g., United States v.
McMillan, 744 F.3d 1033, 1038 (7th Cir. 2014); Miller, 673 F.3d at
696 (explaining that “if applied mechanically,” the permitted
purposes listed in the rule “would overwhelm the central
principle” of the rule against propensity evidence (quoting
Beasley, 809 F.3d at 1279)).




3
 (...continued)
identify situations in which the rule of subsection (1) by its terms does not
apply.
No. 12-1104                                                   15

    To resolve this inherent tension in the rule, we have
cautioned that it’s not enough for the proponent of the other-
act evidence simply to point to a purpose in the “permitted”
list and assert that the other-act evidence is relevant to it.
Rule 404(b) is not just concerned with the ultimate conclusion,
but also with the chain of reasoning that supports the non-
propensity purpose for admitting the evidence. United States v.
Reed, 744 F.3d 519, 524–25 (7th Cir. 2014); United States v. Lee,
724 F.3d 968, 976–77 (7th Cir. 2013); Miller, 673 F.3d at 697–98.
In other words, the rule allows the use of other-act evidence
only when its admission is supported by some propensity-free
chain of reasoning. Lee, 724 F.3d at 978 (“When one looks
beyond the purposes for which the evidence is being offered
and considers what inferences the jury is being asked to draw
from that evidence, and by what chain of logic, it will some-
times become clear … that despite the label, the jury is essen-
tially being asked to rely on the evidence as proof of the
defendant’s propensity to commit the charged offense.”);
Miller, 673 F.3d at 697–99; United States v. Jones, 389 F.3d 753,
757 (7th Cir. 2004), vacated on other grounds by Jones v. United
States, 545 U.S. 1125 (2005). This is not to say that other-act
evidence must be excluded whenever a propensity inference
can be drawn; rather, Rule 404(b) excludes the evidence if its
relevance to “another purpose” is established only through the
forbidden propensity inference.
   Spotting a hidden propensity inference is not always easy.
See Jones, 389 F.3d at 757. For this reason, although we have
long required the record to reflect a “principled exercise of
discretion” by the district court, Beasley, 809 F.2d at 1279, we
16                                                    No. 12-1104

have more recently emphasized the importance of identifying
the non-propensity theory that makes the other-act evidence
relevant and specifically asking how the evidence tends to
make a particular fact of consequence more or less probable.
For example, in United States v. Ciesiolka, 614 F.3d 347, 355 (7th
Cir. 2010), we noted that it was critical to “delineate precisely
the legitimate ends to which the evidence could be applied.” In
Miller we explained that the court should ask “more specifi-
cally how” the other-act evidence is relevant to a permitted
purpose in order to help expose impermissible uses of other-
act evidence for pure propensity purposes. 673 F.3d at 699. In
United States v. Richards, 719 F.3d 746 (7th Cir. 2013), we said
that the “district court[] must consider specifically how the prior
conviction tends to serve the non-propensity exception.” Id. at
759 (internal quotation marks and alterations omitted). And in
Lee we explained that the court must “consider the chain of
logic by which the jury is being asked to glean the defendant’s
knowledge, intent, etc., from proof of his prior misdeeds.”
724 F.3d at 976–77.
   The principle that emerges from these recent cases is that
the district court should not just ask whether the proposed
other-act evidence is relevant to a non-propensity purpose but
how exactly the evidence is relevant to that purpose—or more
specifically, how the evidence is relevant without relying on a
propensity inference. Careful attention to these questions will
help identify evidence that serves no permissible purpose.
No. 12-1104                                                                17

    3. Rule 403
    Finally, even if other-act evidence is relevant without
relying on a propensity inference, it may be excluded under
Rule 403, which applies “with full force” in this context, Miller,
673 F.3d at 696, and gives the district court discretion to
exclude relevant evidence if its probative value is “substan-
tially outweighed by a danger of … unfair prejudice,” FED. R.
EVID. 403. Other-act evidence raises special concerns about
unfair prejudice because it almost always carries some risk that
the jury will draw the forbidden propensity inference.4 See Lee,
724 F.3d at 976 (describing the “inherent risk of prejudice that
such evidence poses to the defendant.”). Rule 403 does much
of the heavy lifting in the admissibility analysis by excluding
other-act evidence that may be slightly probative through a
non-propensity theory but has a high likelihood of creating
unfair prejudice by leading a jury to draw conclusions based
on propensity. See Miller, 673 F.3d at 697 (explaining that under
Rule 403 “all bad acts evidence must be balanced for probative
value and unfair prejudice”); United States v. Chapman, 692 F.3d
822, 827 (7th Cir. 2012) (“The admission of [other-act] evidence
always carries with it some risk of unfair prejudice to the
defendant, but the critical issue is whether that risk is suffi-
ciently outweighed by other factors.”).


4
  Rule 403 also gives the court discretion to exclude relevant evidence if its
probative value is substantially outweighed by the danger of “confusing the
issues, misleading the jury, undue delay, wasting time, or needlessly
presenting cumulative evidence.” FED. R. EVID. 403. Other-act evidence may
implicate these concerns as well, but the more common problem is the risk
of unfair prejudice.
18                                                   No. 12-1104

       i. The degree to which a fact is contested
    One important issue in Rule 403 balancing in this context is
the extent to which the non-propensity factual proposition
actually is contested in the case. For example, if a defendant
offers to concede or stipulate to the fact for which the evidence
is offered, additional evidence may have little probative value.
See, e.g., Old Chief v. United States, 519 U.S. 172, 191–92 (1997)
(holding that a defendant’s stipulation to a prior felony
conviction removes its probative value in a prosecution for
unlawful possession of a firearm by a felon). Of course, there
are various degrees of factual disagreement in a trial, and
stipulations are at one end of that spectrum. See generally
2 EDWARD J. IMWINKELRIED, UNCHARGED MISCONDUCT EVI-
DENCE §§ 8:10–15 (2004) (reviewing various forms of disagree-
ment and their effect on the admissibility of other-act evi-
dence). Because each case is unique, Rule 403 balancing is a
highly context-specific inquiry; there are few categorical rules.
See Miller, 673 F.3d at 696–97. The general guiding principle is
that the degree to which the non-propensity issue actually is
disputed in the case will affect the probative value of the other-
act evidence. See United States v. Causey, 748 F.3d 310, 318 (7th
Cir. 2014); Lee, 724 F.3d at 976; Miller, 673 F.3d at 696–97.
    On the other hand, there are a few discrete circumstances in
which we can say as a categorical matter that other-act evi-
dence is substantially more prejudicial than probative. The
Supreme Court’s decision in Old Chief is one example. There,
the defendant was charged with unlawful possession of a
firearm by a felon and offered to stipulate to his status as a
felon to prevent the jury from learning the details of his prior
No. 12-1104                                                       19

conviction. The government rejected his offer to stipulate, and
the district court permitted the prosecutor to introduce the
prior conviction over the defendant’s Rule 403 objection.
519 U.S. at 177–78.
    The Supreme Court reversed. Id. at 192. The Court began by
acknowledging the “familiar, standard rule that the prosecu-
tion is entitled to prove its case by evidence of its own choice,
or, more exactly, that a criminal defendant may not stipulate or
admit his way out of the full evidentiary force of the case as the
Government chooses to present it.” Id. at 186–87. But when a
defendant’s status as a felon is an element of the offense and he
offers to stipulate to that fact, the evidence of his prior convic-
tion loses its probative value, leaving only a substantial risk of
unfair prejudice. Id. at 191–92. In this specific situation, a
district court abuses its discretion in admitting the details of
the prior conviction. Id.
    Our circuit also requires special caution when other-act
evidence is offered to prove intent, which though a permissible
non-propensity purpose is nonetheless “most likely to blend
with improper propensity uses.” Miller, 673 F.3d at 698. In
cases involving general-intent crimes—e.g., drug-distribution
offenses (as distinct from drug conspiracies or possession of
drugs with intent to distribute)—we have adopted a rule that
other-act evidence is not admissible to show intent unless the
defendant puts intent “at issue” beyond a general denial of
guilt. See, e.g., United States v. Hicks, 635 F.3d 1063, 1070–71 (7th
Cir. 2011); Shackleford, 738 F.2d at 781, overruled in part on other
grounds by Huddleston v. United States, 485 U.S. 681. Our most
complete explanation of this rule comes from Shackleford:
20                                                       No. 12-1104

       We have previously distinguished between
       situations in which intent is in issue because the
       government must show specific intent as an
       essential element of the crime and when intent is
       only a formal issue that can be inferred from the
       act. When the crime charged requires proof of
       specific intent, we have held that, because it is a
       material element to be proved by the govern-
       ment, it is necessarily in issue and the govern-
       ment may submit evidence of other acts in an
       attempt to establish the matter in its case-in-
       chief, assuming the other requirements of
       Rules 404(b) and 403 are satisfied. … On the
       other hand, we have stated that when intent is
       only a formal issue, so that proof of the proscribed act
       gives rise to an inference of intent, then unless the
       government has reason to believe that the de-
       fense will raise intent as an issue, evidence of
       other acts directed toward this issue should not
       be used in the government’s case-in-chief and
       should not be admitted until the defendant raises
       the issue.
738 F.2d at 781 (emphasis added).
    The specific-intent/general-intent distinction in the
Rule 404(b) context is sometimes misunderstood. The critical
point is that for general-intent crimes, the defendant’s intent
can be inferred from the act itself, so intent is not “automati-
cally” at issue. The paradigm case involves a charge of distri-
bution of drugs, see Hicks, 635 F.3d at 1070–71, a general-intent
No. 12-1104                                                      21

crime for which the government need only show that the
defendant physically transferred the drugs; the jury can infer
from that act that the defendant’s intent was to distribute them.
Hence our rule that “[b]ecause unlawful distribution [of drugs]
is a general intent crime, in order for the government to
introduce prior bad acts to show intent, the defendant must
put his intent at issue first.” Id.; see also United States v.
Manganellis, 864 F.2d 528, 539 (7th Cir. 1988).
     In contrast, we have repeatedly rejected a similar rule for
specific-intent crimes because in this class of cases “intent is
automatically at issue.” United States v. Conner, 583 F.3d 1011,
1022 (7th Cir. 2009) (collecting cases). Unfortunately, this line
of precedent too frequently has been seen as a rule of auto-
matic admission for other-act evidence in cases of specific-
intent crimes. See Lee, 724 F.3d at 981; Miller, 673 F.3d at 698–99.
We firmly rejected that notion in Miller, emphasizing that
other-act evidence is always subject to Rule 403 balancing.
673 F.3d at 696–98. We explained that although “[i]ntent can be
‘automatically at issue’ because it is an element of a specific
intent crime,” other-act evidence offered to prove intent “can
still be completely irrelevant to that issue, or relevant only in
an impermissible way.” Id. at 697–98. We have reiterated these
themes in other recent cases. See, e.g., Lee, 724 F.3d at 976
(“Simply because a subject like intent is formally at issue when
the defendant has claimed innocence and the government is
obliged to prove his intent as an element of his guilt does not
automatically open the door to proof of the defendant’s other
wrongful acts for purposes of establishing his intent.”); United
States v. Earls, 704 F.3d 466, 471 (7th Cir. 2012) (“Rule 404(b)
22                                                    No. 12-1104

does not provide a rule of automatic admission whenever bad
acts evidence can be plausibly linked to another purpose … .
The Rule 402 requirement of relevance and the unfair prejudice
balancing inquiries of Rule 403 still apply with full force.”
(internal quotation marks omitted)).
    To summarize then, when intent is not “at issue”—when
the defendant is charged with a general-intent crime and does
not meaningfully dispute intent—other-act evidence is not
admissible to prove intent because its probative value will
always be substantially outweighed by the risk of unfair
prejudice. In contrast, when intent is “at issue”—in cases
involving specific-intent crimes or because the defendant
makes it an issue in a case involving a general-intent crime—
other-act evidence may be admissible to prove intent, but it
must be relevant without relying on a propensity inference,
and its probative value must not be substantially outweighed
by the risk of unfair prejudice. And again, the degree to which
the non-propensity issue actually is contested may have a
bearing on the probative value of the other-act evidence.
    Before moving on, we pause to note a point raised by the
government that one of our recent cases could be read to
suggest a generally applicable rule that other-act evidence may
not be admitted unless the defendant “meaningfully
dispute[s]” the non-propensity issue for which the evidence is
offered. Richards, 719 F.3d at 759 (citing Miller, 673 F.3d at 697).
Richards never actually held that, but for clarity’s sake, we
reiterate that there is no such categorical rule or prerequisite,
and we decline to adopt one now. Nothing in the Rules of
Evidence supports imposing such a universal prerequisite to
No. 12-1104                                                    23

the admission of other-act evidence. Indeed, the advisory
committee explicitly disapproves of any general requirement
of this sort. See FED. R. EVID. 401 advisory committee’s notes
(1972) (“The fact to which the evidence is directed need not be
in dispute. … [T]he ruling should be made on the basis of such
considerations as waste of time and undue prejudice (see
Rule 403), rather than under any general requirement that
evidence is admissible only if directed to matters in dispute.”);
FED. R. EVID. 404 advisory committee’s notes (1972) (“No
mechanical solution is offered.”). Moreover, as we have noted,
the Supreme Court has specifically endorsed “the accepted rule
that the prosecution is entitled to prove its case free from any
defendant’s option to stipulate the evidence away.” Old Chief,
519 U.S. at 189. The Court held in Old Chief that “if … there [is]
a justification for receiving evidence of the nature of prior acts
on some issue other than status (i.e., to prove motive, opportu-
nity, intent, preparation, plan, knowledge, identity, or absence
of mistake or accident … ), Rule 404(b) guarantees the opportu-
nity to seek its admission.” Id. at 190 (internal quotation marks
omitted).
    Though not a fixed requirement, we reiterate that the
district court should consider the degree to which the non-
propensity issue actually is contested when evaluating the
probative value of the proposed other-act evidence. Because
other-act evidence almost always carries a risk of unfair
prejudice, sensitivity to the real factual disputes in the case is
critical to meaningful Rule 403 balancing.
24                                                    No. 12-1104

                             *   *   *
    In sum, to overcome an opponent’s objection to the
introduction of other-act evidence, the proponent of the
evidence must first establish that the other act is relevant to a
specific purpose other than the person’s character or propen-
sity to behave in a certain way. See FED. R. EVID. 401, 402,
404(b). Other-act evidence need not be excluded whenever a
propensity inference can be drawn. But its relevance to
“another purpose” must be established through a chain of
reasoning that does not rely on the forbidden inference that the
person has a certain character and acted in accordance with
that character on the occasion charged in the case. If the
proponent can make this initial showing, the district court
must in every case assess whether the probative value of the
other-act evidence is substantially outweighed by the risk of
unfair prejudice and may exclude the evidence under Rule 403
if the risk is too great. The court’s Rule 403 balancing should
take account of the extent to which the non-propensity fact for
which the evidence is offered actually is at issue in the case.


       ii. Jury instructions
    Appropriate jury instructions may help to reduce the risk
of unfair prejudice inherent in other-act evidence. See, e.g.,
United States v. Carter, 695 F.3d 690, 702 (7th. Cir. 2012); FED. R.
EVID. 403 advisory committee’s notes (1972) (explaining that
the effectiveness of limiting instructions are a factor in weigh-
ing the danger of unfair prejudice). A limiting instruction must
be given upon request. See FED. R. EVID. 105. But a defendant
No. 12-1104                                                     25

may choose to go without one to avoid highlighting the
evidence. See Jones, 455 F.3d at 811 (Easterbrook, J., concurring).
We caution against judicial freelancing in this area; sua sponte
limiting instructions in the middle of trial, when the evidence
is admitted, may preempt a defense preference to let the
evidence come in without the added emphasis of a limiting
instruction. The court should consult counsel about whether
and when to give a limiting instruction.
    Rule 404(b) already requires that the prosecutor notify the
defendant before trial of an intent to use other-act evidence,
provided the defense has requested this notice (though the
judge may excuse a lack of pretrial notice for good cause). See
FED. R. EVID. 404(b)(2)(A)–(B). Motions in limine are common
even in the absence of a defense request for notice. As soon as
it becomes clear that other-act evidence may be part of the
prosecution’s case, the district judge should raise with the
defendant whether the defense wants a limiting instruction
(since Rule 105 requires it to be given on request) and, if so,
what kind.
    When given, the limiting instruction should be customized
to the case rather than boilerplate. Id. at 811–12 (“A good
limiting instruction needs to be concrete so that the jury
understands what it legitimately may do with the evidence.”).
In order to “effectively distinguish appropriate from inappro-
priate inferences,” id. at 812, jurors should be told in plain
language the specific purpose for which the evidence is offered
and that they should not draw any conclusions about the
defendant’s character or infer that on a particular occasion the
defendant acted in accordance with a character trait. Our
26                                                    No. 12-1104

circuit’s Pattern Jury Instruction 3.11 is a good starting point,
but it needs customization for the particular case.
    Moreover, we see no reason to keep the jury in the dark
about the rationale for the rule against propensity inferences.
Lay people are capable of understanding the foundational
principle in our system of justice that “we try cases, rather than
persons.” People v. Allen, 420 N.W.2d 499, 504 (Mich. 1988); see
also United States v. Linares, 367 F.3d 941, 945 (D.C. Cir. 2004)
(explaining that a component of the presumption of innocence
is that “a defendant must be tried for what he did, not for who
he is”); 1 IMWINKELRIED, supra, § 1:3 (2004) (explaining that the
rule against propensity evidence guards against the illicit
temptation to “penalize the defendant for his or her past
misdeeds”). The court’s limiting instruction would be more
effective if it told the jurors that they must not use the other-act
evidence to infer that the defendant has a certain character and
acted “in character” in the present case because it does not
follow from the defendant’s past acts that he committed the
particular crime charged in the case.
    Finally, the instruction would be improved by tying the
limiting principle to the prosecution’s burden of proof. The
jurors should be reminded that the government’s duty is to
prove beyond a reasonable doubt every element of the specific
crime charged, and it cannot discharge its burden by inviting an
inference that the defendant is a person whose past acts
suggest a willingness or propensity to commit crimes.
No. 12-1104                                                    27

B. Application of a Rules-Based Framework
   Here, the district court allowed the government to use the
evidence of the user quantity of cocaine found in Gomez’s
bedroom for the purpose of proving his identity as Guero. That
was error, but for reasons we will explain, the error was
harmless.


   1. The Evidence Was Relevant Only Through a Propensity
       Inference
    Because the proponent of the other-act evidence must
explain how it is relevant to a non-propensity purpose, the
government needed a rationale for connecting the cocaine
found in Gomez’s bedroom to his identity as Guero without
relying on the forbidden propensity inference. As we’ve discussed,
one accepted way to use other-act evidence to prove identity
is to argue that the perpetrator had a distinctive modus
operandi. Gomez suggests that we should limit the “identity”
uses of other-act evidence to this theory. We see no reason to
do so. Indeed, we have previously said that modus operandi
is not the exclusive theory for admitting other acts to prove
identity. Simpson, 479 F.3d at 498. Accordingly, we reject
Gomez’s invitation to artificially limit the ways in which other-
act evidence can be admitted to prove identity. At the same
time, however, a defense of mistaken identity does not by itself
give the government a green light to use other-act evidence.
   To support its identity theory of relevance here, the
government relies on two cases in which other-act evidence
was admitted in response to a defense of mistaken identity:
28                                                    No. 12-1104

United States v. Brown, 471 F.3d 802 (7th Cir. 2006), and United
States v. Gibson, 170 F.3d 673 (7th Cir. 1999). Brown is inapplica-
ble. There, the defendant was alleged to have participated in a
drug transaction that was interrupted by the police. He fled the
scene, but another man involved in the deal was apprehended
and agreed to cooperate with law enforcement. 471 F.3d at 804.
The cooperator identified Brown as the drug buyer who fled
the scene when the police arrived. Brown’s defense was
mistaken identity—he claimed that he had nothing to do with
the cooperator—not on this specific occasion or at any other
time. Id. at 806. In response the government introduced
evidence that Brown had purchased drugs from the cooperator
on many prior occasions. We approved this use of other-act
evidence because it undercut Brown’s claim that the cooperator
was lying. Id.
    The basic theory of admissibility in Brown—that evidence
of other transactions between the defendant and a witness is
admissible to bolster the witness’s identification of the defen-
dant as a participant in the charged transaction—is a distinct
and widely acknowledged theory of admissibility under
Rule 404(b). See 1 IMWINKELRIED, supra, § 3:7 (2006). But it has
no application in this case. The other-act evidence here—a user
quantity of cocaine found in Gomez’s bedroom 26 days after
the conspiracy ended—did not serve that purpose.
    Gibson is more on point. Gibson was charged with distribut-
ing cocaine in 1996. His defense was that it was not him, but his
brother, who sold the cocaine. In response the government
introduced Gibson’s postarrest statement to the FBI that he
regularly sold cocaine from 1994 to 1997 (he denied involve-
No. 12-1104                                                   29

ment in the particular sale at issue in the case). We upheld the
prosecution’s use of Gibson’s statement about his history of
drug dealing “because his primary defense at trial was that of
mistaken identity.” Gibson, 170 F.3d at 679.
    Gibson is hard to square with United States v. Simpson,
479 F.3d 492, a nearly identical case that reached the opposite
conclusion. Simpson was charged with selling cocaine, and as
in Gibson his defense was mistaken identity. The government
introduced Simpson’s statement to the FBI admitting that he
had been dealing cocaine for three or four years leading up to
the charged crime. We held that this evidence was improperly
admitted to prove identity because it could only be relevant to
that issue by way of an impermissible propensity inference. Id.
at 497–98. We distinguished Gibson by highlighting that Gibson
had specifically pointed the finger at an alternative culprit—his
brother—and that Gibson’s history of drug dealing made it
more likely that he—not his brother—was the drug dealer. Id.
at 499 n.1. In contrast, Simpson argued more generally that the
police had the wrong guy. Id.
    Here, as in Gibson, Gomez’s mistaken-identity defense
singled out another person—his brother-in-law and housemate
Victor Reyes—as the “real” Guero. The government intro-
duced the user quantity of cocaine found in Gomez’s bedroom
for the purpose of showing that as between the two, it was
more likely that Gomez was Guero. If the distinction drawn in
Simpson is valid, then Gibson controls as the more closely
analogous precedent. But the distinction does not hold up.
Simpson relied on a supposed difference in the probative value
of propensity evidence when a mistaken-identity defense
30                                                      No. 12-1104

focuses on a particular alternative suspect rather than arguing
mistaken identity more generally. But Rule 404(b) does not
allow propensity evidence when it is probative enough; it bars
propensity evidence as a categorical matter. In Gibson, just as
in Simpson, the evidence of the defendant’s history of drug
dealing tended to prove his identity as a participant in the
charged drug deal only by way of a forbidden propensity
inference: Once a drug dealer, always a drug dealer. Gibson
and Simpson cannot be reconciled. We now conclude that
Gibson did not survive our recent decisions in Miller and Lee.
    This case is yet another example of the importance of
asking how exactly the proposed other-act evidence is relevant
without relying on propensity. The government maintains that
the cocaine found in Gomez’s bedroom was admissible because
it made it more probable that Gomez—not Reyes—was Guero.
But that is just to say that the evidence is relevant; it doesn’t tell
us how the evidence is relevant in a propensity-free way. On that
pivotal question, the government has little to offer.
    If there had been some basis to argue that the cocaine in
Gomez’s bedroom was the product of the conspiracy, then it
might have qualified as direct evidence of Gomez’s participa-
tion in Romero’s drug ring and Rule 404(b) would not apply.
See United States v. Philips, 745 F.3d 829, 833 (7th Cir. 2014);
United States v. Adams, 628 F.3d 407, 414 (7th Cir. 2010); United
States v. Alviar, 573 F.3d 526, 538 (7th Cir. 2009). But the
government doesn’t make that argument, for good reason. The
cocaine in Gomez’s room was a small user quantity; it was half
as pure as the quarter kilogram of cocaine found in Romero’s
No. 12-1104                                                       31

car; and it was recovered almost four weeks after Romero and
Gomez ceased doing business together.
    In the end, the government offers no theory other than
propensity to connect the cocaine found in Gomez’s bedroom
to his identity as Guero, Romero’s coconspirator. The govern-
ment’s sole theory is that Gomez’s possession of a user
quantity of cocaine 26 days after the conspiracy ended shows
that he, rather than Reyes, was Guero. That argument is
extraordinarily weak, but the more important point is that it
rests on pure propensity: Because Gomez possessed a small
quantity of cocaine at the time of his arrest, he must have been
involved in the cocaine-distribution conspiracy. The district
court should not have admitted this evidence.


   2. The Error Was Harmless
    Evidentiary errors are subject to review for harmlessness.
See FED. R. CRIM. P. 52(a); McMillan, 744 F.3d at 1077; United
States v. Vargas, 689 F.3d 867, 875 (7th Cir. 2012). In this context,
“[t]he test for harmless error is whether, in the mind of the
average juror, the prosecution’s case would have been signifi-
cantly less persuasive had the improper evidence been ex-
cluded.” Vargas, 689 F.3d at 875 (citing United States v. Loughry,
660 F.3d 965, 975 (7th Cir. 2011)). The evidence identifying
Gomez as Guero was quite compelling and would not have
been less so had the other-act evidence been excluded.
   First, Romero addressed his coconspirator as “Guero” in
numerous recorded phone calls, confirming that it was always
the same person on the other end of the line in the months
32                                                No. 12-1104

leading up to the September 3 transaction. GPS data showed
Romero driving to the alley behind Gomez’s house after
arranging sales with Guero. On September 2 Romero again
called Guero to arrange a cocaine sale for the next day. Romero
drove to Milwaukee on September 3 as planned and parked his
Mercedes near Gomez’s house, consistent with past practice.
Federal agents observed—and a videorecording captured—a
brief conversation between Gomez and Romero as they stood
next to the Mercedes. Importantly, when the two men parted
company and left on foot in opposite directions, the agents
stopped Gomez, asked for his identification, and he gave them
the same phone number that Guero had used to set up the sale
that day. Later that day the agents seized and searched the
abandoned Mercedes and found a quarter kilogram of cocaine
in the trunk.
   Next, the jury heard other evidence corroborating Gomez’s
identity as Guero. The three cell phones Guero used were
registered to the house on Mineral Street that Gomez shared
with Reyes, but the bills were sent to Gomez at that address,
and he had one of the bills in a box in his bedroom. True, the
phones could be linked to Reyes too, and Reyes joined Romero
and Gomez at the meeting at El Rey after Gomez was stopped
and searched by DEA agents. So it’s no wonder Gomez
focused his defense on pointing the finger at Reyes.
    But other evidence convincingly refuted the theory that
Reyes was Guero. During Gomez’s postarrest interview,
federal agents played several of the recorded phone calls for
him, including one that took place after the aborted cocaine
sale on September 3. Gomez admitted that Guero’s voice on
No. 12-1104                                                                 33

the recordings was his. This admission is quite powerful on its
own, but because Gomez challenged the agents’ credibility, we
press on with our harmless-error analysis. See United States v.
Robinson, 724 F.3d 878, 888 (7th Cir. 2013).
    In a recorded phone call on September 4 retracing the
events of the previous day, Guero describes in the first person
how the police stopped him as he walked away from his
conversation with Romero; we know that happened to Gomez,
not Reyes. Earlier in that same phone call Romero asked Guero
what happened to Reyes, and Guero responded with an
account in the third person about what happened to his brother-
in-law after the three men left El Rey.5 Finally, when Gomez


5
  Our dissenting colleagues object that the government did not press this
interpretation of the September 4 phone call before the jury. We disagree.
It’s true that the prosecutor did not specifically contrast the agents’ stop of
Gomez (on foot) and Reyes (in his car). But the prosecutor discussed the
September 4 phone call in some detail in closing argument, explaining that:
        [I]n another call, Call 64171, Gomez says—Gomez tells
        Romero that Gomez had been stopped when he was
        walking and had turned the corner. Now it’s no coinci-
        dence that Guero, the man on this phone with Roberto
        Romero, is telling Romero about a stop that occurred—that
        occurred to him that day exactly the same way it happened
        to Nicolas Gomez that day. It’s no coincidence because
        Nicolas Gomez is Guero. The context of these calls,
        combined with the other evidence, is just one more kind of
        proof that Nicolas Gomez was Roberto Romero’s partner
        in all of these calls.
After touching on some of the other evidence, the prosecutor returned to
this point, telling the jurors that they could be confident beyond a
                                                           (continued...)
34                                                        No. 12-1104

was arrested at his home nearly four weeks after the conspir-
acy ended, his wallet was found on the kitchen table right next
to the phone Guero had used since September 3.
    In short, the prosecution’s case was strong and would not
have been any less persuasive had the other-act evidence been
excluded—or at least it would not have been significantly less
persuasive in the mind of the average juror. The link between
the small quantity of cocaine found in Gomez’s bedroom and
his identity as Guero was extremely weak; the government has
never really articulated a coherent theory for why this evi-
dence helped its case. Excluding it would not have seriously
diminished the strength of the prosecution’s case against
Gomez. We’re satisfied that the error was harmless.
                                                            AFFIRMED.




5
 (...continued)
reasonable doubt that Gomez was Guero “because of the context of the
post-stop phone calls where [Guero] talks about things that only happened
to Nicolas Gomez.”
No. 12-1104                                                35

   HAMILTON, Circuit Judge, joined by WOOD, Chief Judge,
and ROVNER and WILLIAMS, Circuit Judges, concurring in part
and dissenting in part. The en banc court agrees unanimous-
ly that the district court erred by admitting under Rule
404(b) the evidence that Gomez was in possession of a small
amount of cocaine nearly four weeks after the charged con-
spiracy ended. Its admission was not justified on any of the
three grounds accepted by the district court and argued by
the government to the jury. Judge Sykes’ opinion for the
court on the merits of the Rule 404(b) question takes im-
portant and welcome steps to clarify this troublesome area of
evidence law. See generally United States v. Gomez, 712 F.3d
1146, 1159–63 (7th Cir. 2013) (Hamilton, J., dissenting). I
therefore join Parts II-A and II-B-1 of Judge Sykes’ opinion.
    Those joining this opinion also take this opportunity to
provide an example of the type of jury instruction that
should be given when evidence is admitted properly under
Rule 404(b). Suppose the facts here had been different. Sup-
pose (1) that Gomez had later possessed a wholesale quanti-
ty of cocaine of the same purity as the cocaine involved in
the conspiracy, (2) that the government had shown that the
cocaine would be probative of Gomez’s identity and not un-
fairly prejudicial, and (3) that the defendant wanted a limit-
ing instruction. A good instruction consistent with our cir-
cuit’s Pattern Instruction 3.11 would be:
      You have heard testimony that the defendant
   committed acts other than the ones charged in the in-
   dictment. Before using this evidence, you must decide
   whether it is more likely than not that the defendant
   took the actions that are not charged in the indict-
   ment. If you decide that he did, then you may consid-
36                                                  No. 12-1104

     er that evidence to help you decide whether the de-
     fendant was the same person as the one called
     “Guero.” You may not consider this evidence for any
     other purpose. To be more specific, you may not infer
     that, because the defendant committed an act in the
     past, he must have committed the crimes charged in
     the indictment. The reason is that the defendant is on
     trial here for specific charges of conspiracy to possess
     cocaine with intent to distribute and using a tele-
     phone to facilitate a drug crime. He is not on trial for
     those other acts. It is the government’s burden to
     prove beyond a reasonable doubt the elements of the
     specific crimes charged here. The government cannot
     meet its burden by inviting you to infer that the de-
     fendant is a person whose past acts suggest he has a
     bad character or a tendency to commit crimes.
    Nevertheless, after having done so much to improve our
circuit’s law under Rule 404(b), the en banc majority still af-
firms Gomez’s conviction despite the serious Rule 404(b) er-
ror. The majority does so by finding that the Rule 404(b) er-
ror was harmless, in Part II-B-2 of its opinion. From this con-
clusion and the resulting affirmance, I respectfully dissent.
We should reverse this conviction and remand for a new tri-
al without the highly prejudicial evidence admitted errone-
ously under Rule 404(b).
    To be sure, the government’s case against the person
called “Guero” was air-tight. But was Gomez “Guero”? The
government offered substantial evidence that he was. But
that evidence is not as clear as the majority contends, partic-
ularly when we keep in view the requirement of proof be-
yond a reasonable doubt. The applicable standard for harm-
No. 12-1104                                                     37

less error is provided by Federal Rule of Criminal Procedure
52(a), which requires the court to disregard an error that
“does not affect substantial rights.” The burden is on the
government to show that the error here was harmless. United
States v. Olano, 507 U.S. 725, 734 (1993); United States v. Patter-
son, 23 F.3d 1239, 1255 (7th Cir. 1994).
    To avoid a finding of harmless error, the defendant “need
not show that, on remand, a jury would not convict him a
second time.” United States v. Richards, 719 F.3d 746, 765–66
(7th Cir. 2013). Even where the defendant “probably” still
would have been convicted in the absence of improper pro-
pensity evidence, the error is not necessarily harmless. Id.
The proper question is “whether an average juror would
find the prosecution’s case significantly less persuasive
without the improper evidence.” United States v. Miller, 673
F.3d 688, 700 (7th Cir. 2012); see also Kotteakos v. United
States, 328 U.S. 750, 765 (1946) (in case of non-constitutional
error, question is whether we can say “with fair assurance”
that verdict was not substantially swayed by error).
    Because Rule 404(b) evidence can be so powerful and
prejudicial, we have found the improper admission of other-
acts drug evidence harmful despite otherwise quite strong
evidence of guilt. See, e.g., United States v. Lee, 724 F.3d 968,
982–83 (7th Cir. 2013) (Rule 404(b) error was not harmless
although cocaine was found in trunk of car defendant was
driving, cocaine’s packaging had defendant’s fingerprint on
it, witness testified that defendant sold him cocaine, and
phone records connected defendant to witness); Miller, 673
F.3d at 701-02 (erroneous admission of prior drug conviction
was not harmless despite substantial evidence of guilt). Even
when 404(b) evidence is admitted properly but is then used
38                                                No. 12-1104

improperly to show propensity, we have found the error to
be harmful. See, e.g., Richards, 719 F.3d at 763–66. In this
case, the entire court agrees that the 404(b) evidence should
not have been admitted at all because its only use was to
show propensity.
   The agents never did catch the conspirators in the act, as
they sought to do on September 3, 2010. So let’s consider the
government’s evidence indicating that Guero was Gomez
rather than his brother-in-law Victor Reyes, who lived in the
same house and who was also observed meeting with the
supplier, Romero, on September 3.
    An FBI agent and a linguist testified that they played
three recorded phone calls for Gomez when they inter-
viewed him after his arrest, and that he identified his own
voice as Guero on those calls. That testimony depends en-
tirely on the credibility of the federal agents, however. They
did not record this critical admission by Gomez orally or in
writing. Such testimony from federal law enforcement offic-
ers is substantial evidence, of course, but the jury was not
required to believe it.
    As between Gomez and Reyes, the physical evidence
found in the search was ambiguous. The agents found one of
the cell phones Guero had used. The billing statements for
all three phones Guero had used were addressed to Gomez,
but the phones were registered under Reyes’s name. That
evidence does not really help decide which one was Guero.
   The majority’s strongest evidence that Gomez was Guero
comes from telephone calls between Romero and Guero after
the September 3 seizure of Romero’s car with the cocaine
hidden in it. In a September 3 phone call at 9:27 p.m., Guero
No. 12-1104                                                 39

described someone other than himself being stopped by po-
lice, but the exchange is ambiguous:
   Romero: But were they following you as well or not?
   Guero:     Not me, cousin, not any more. The only one
              they stopped was – since I saw that my
              brother-in-law left. They stopped him there
              at the school.
   Romero: Him too?
   Guero:     Yes.
   Romero: What did they ask him or what?
   Guero:     Eh, that if he had something, if he had
              weapons or something, because they were
              supposedly looking for someone who had a
              weapon.
Doc. 72 at 184–85 (Call No. 34800). The agents stopped both
Gomez and Reyes on September 3. Each could describe the
other as his brother-in-law, so this exchange does not resolve
the issue.
   The majority finds more support from a call at 9:29 a.m.
on September 4 but describes the conversation as including
more specific details than it actually did. According to the
majority:
       In a recorded phone call on September 4 retracing
   the events of the previous day, Guero describes in the
   first person how the police stopped him as he walked
   away from his conversation with Romero; we know
   that happened to Gomez, not Reyes. Earlier in that
   same phone call Romero asked Guero what happened
   to Reyes, and Guero responded with an account in the
40                                                No. 12-1104

     third person about what happened to his brother-in-
     law after the three men left El Rey.
Ante at 33. Guero did not actually give Romero such explicit
information about timing. Although he may well have been
referring to a stop of himself on the previous day, he did not
say so. And although Romero also may well have been ask-
ing Guero about Reyes being stopped (which would of
course indicate that Guero was not Reyes), the name Reyes
was never mentioned between them. As translated from
Spanish in the official transcript, the key exchange went like
this:
     Romero: It seems like your brother – your brother-in-
             law – what happened when he came from
             over there? He had another car from that
             guy, right?
     Guero:   Yes. He was stopped by a sheriff.
     Romero: What did they tell him or what?
     Guero:   They – just that he was – they wanted him
              to give them permission to search his car.
              They – that they had seen him come out of
              El Rey over here. They asked him if he had
              gone to the – to get tacos or what. What did
              he go there for?
     Romero: Is that they seen the three of us come out
             here?
     Guero:   Uh-huh.
     Romero: And to you, if they saw us all together, why
             – I don’t understand why. How did it hap-
             pen to you also?
No. 12-1104                                                 41

   Guero:     I beg your pardon?
   Romero: You also said that when you came over to
           the little village, you were searched. I don’t
           understand why.
   Guero:     Well, when I was turning the corner –
   Romero: You were walking, right?
   Guero:     Yes.
Doc. 72 at 189 (Call No. 64171). A moment later in the same
call, however, Romero seemed to treat the car as Guero’s.
Reyes was driving the car when it was stopped and taken by
the agents. The context is difficult to interpret, but Romero
and Guero were still talking about the events of September 3
and the seizure of the car:
   Romero: Those guys see each other every once in a
           while. How were they doing over there?
           What are they doing? They have plates.
           They have personal plates from over there.
           But that’s how those guys are doing it.
   Guero:     Then from what I understand, they – when
              they bring those plates is when they bring
              someone from over there. Supposedly to
              get a person, that’s when they come out.
   Romero: Imagine. It can’t be. I don’t understand. It’s
           strange, not this dude. What did they want?
           What were they expecting? I don’t know
           what the fuck. They wanted to maybe stop
           you also since you also went in there in the
           shops and that?
   Guero:     I beg your pardon?
42                                                 No. 12-1104

     Romero: I mean, I don’t know. Maybe they were
             waiting for you to go in, in some house or
             something. I don’t know. If not that they have
             taken your car just like this, dude.
Id. at 190–91.
    The first passage referring to Guero being stopped while
walking now seems to be the strongest evidence that Guero
was Gomez. While that seems to be the most likely reading
of the exchange, I am not persuaded that it renders the seri-
ous Rule 404(b) error harmless.
    First, and most important, the government never made
the argument that the majority makes about the significance
of the phone calls. Its appellate briefs presented only the
most perfunctory harmless error argument and made no
mention of the September 4 phone call. Nor did the govern-
ment make this point at trial. Yes, the government pointed
out that Guero described being stopped on foot in one of the
calls, which is something that happened to Gomez. See Doc.
75 at 14–15. But the prosecutor did not draw the contrast be-
tween the stop of Reyes and the stop of Gomez. The majority
is therefore finding harmless error on an interpretation of
the evidence that the government did not press before the
jury.
   If the majority’s new interpretation of the phone calls had
been presented at trial, Gomez would have had occasion to
challenge it. As it was, there was no need. And if this evi-
dence were decisive, surely the prosecutors would have tak-
en full advantage of it. They did not, so we do not know
whether the majority’s interpretation would have withstood
the adversarial test of trial. The government’s failure to make
No. 12-1104                                                 43

this argument on appeal also means that Gomez never had
an occasion to rebut it in this court.
    Rather than making the majority’s argument, at trial the
government tried to prove identity by emphasizing the erro-
neously admitted Rule 404(b) evidence. Doc. 75 at 32–33. The
prosecutor finished the opening segment of the closing ar-
gument by telling the jury that possession of this user quan-
tity of cocaine, much less pure than the conspiracy ship-
ments, and nearly four weeks after the charged conspiracy
ended, showed Gomez’s identity, as well as knowledge and
absence of mistake. Id. And of course, the district judge told
the jury that the evidence could be used for all three of those
unwarranted purposes. This emphasis by both the govern-
ment and the trial judge is another reason the error in admit-
ting the evidence was not harmless.
     The prosecutors clearly thought the cocaine evidence was
more powerful than the majority’s new theory. I think they
were right. Evidence of cocaine possession in a cocaine con-
spiracy case is especially damning, even if it is not actually
probative of any issue in dispute. In deciding whether an er-
ror was harmless, we do not act as a second jury or try to
guess how the jury would have decided. We ask “whether
an average juror would find the prosecution’s case signifi-
cantly less persuasive without the improper evidence.” Mil-
ler, 673 F.3d at 700.
    Accordingly, while the majority’s treatment of the Rule
404(b) issue is a welcome improvement on our circuit’s law, I
respectfully dissent from the finding that the serious Rule
404(b) error was harmless. I would reverse Gomez’s convic-
tion and remand for a new trial.
