                                PRECEDENTIAL


  UNITED STATES COURT OF APPEALS
       FOR THE THIRD CIRCUIT
            _____________

                 No. 12-1486
                _____________

       UNITED STATES OF AMERICA

                       v.

              TERRELL DAVIS,
                  Appellant
          _______________________

On Appeal from the United States District Court
     for the Eastern District of Pennsylvania
      District Court No. 2-11-cr-00227-003
District Judge: The Honorable R. Barclay Surrick
           _______________________

            Argued March 21, 2013

  Before: McKEE, Chief Judge, SMITH, and
     GREENAWAY, JR., Circuit Judges
                (Filed: August 9, 2013)


Andrew J. Schell [ARGUED]
Office of United States Attorney
615 Chestnut Street
Suite 1250
Philadelphia, PA 19106
       Counsel for Appellee

Christopher G. Furlong [ARGUED]
22 East Third Street
Media, PA 19063
      Counsel for Appellant–Davis

Mark E. Cedrone [ARGUED]
123 South Broad Street
Suite 810
Philadelphia, PA 19109
       Counsel for Appellant–Blackshear1

      1
        We consolidated Terrell Davis’s appeal (No. 12-
1486) and Jamar Blackshear’s appeal (No. 12-1485) for
briefing and argument purposes. Blackshear’s counsel
addressed the suppression issue—which is common to
both defendants—and Davis’s counsel addressed the evi-
dentiary issues. The parties filed two consecutively num-
bered joint appendices (“J.A.”). Davis and Blackshear

                           2
                   ________________

                       OPINION
                   ________________


SMITH, Circuit Judge.
       Police arrested Terrell Davis after finding him in a
Jeep with nearly a kilo of cocaine in the backseat. The
arrest led to a conviction for possession with intent to
distribute. As evidence that Davis recognized the cocaine
in the Jeep, the government proved at trial that he had
two prior convictions for possessing cocaine. Yet the
government never proved that the cocaine from his past
was similar in appearance, quantity, or form. We ac-
knowledge that some of our cases admitting prior crimi-
nal acts under Federal Rule of Evidence 404(b) have
been expansive. But our expansiveness is finite, and this
case crosses the line. We will vacate Davis’s conviction
and remand.
                             I

      The events at issue took place on a wintry after-

also filed separate appendices to their opening briefs
(“D.A.” and “B.A.”).


                            3
noon over two years ago. Two Philadelphia police offi-
cers were patrolling near 5100 Market Street—roughly
four miles west of Independence Hall and the Liberty
Bell. This is a dangerous part of the city where drug deals
and robberies are commonplace. Officer Clifford Gilliam
parked his patrol car, and Officer Shawn Witherspoon
joined him on foot. On the opposite side of the street, the
officers spotted a black Jeep Grand Cherokee, later de-
termined to be from Enterprise Rent-A-Car. Inside were
two men, Terrell Davis and Jamar Blackshear. The Jeep’s
engine was running but nothing seemed amiss.

       After a period of time, Davis and Blackshear be-
gan to act suspiciously. They reached toward each other
with “body motions [that] were consistent with the ex-
changing of narcotics in a narcotics transaction.” B.A. 8.2
The officers exited their patrol car and approached the
Jeep. Upon noticing the officers, Davis and Blackshear
had “expressions of shock on their faces,” B.A. 8, and
they tossed something into the backseat. They exited the
Jeep and quickly walked away—so quickly, in fact, that
Blackshear did not bother closing his door. Officer
Gilliam stopped Blackshear and patted him down to

      2
        The officers did not explain how the “body mo-
tions” were inconsistent with lawful behavior, such as
sharing a meal or exchanging gifts.


                            4
search for weapons. He instead found a wad of cash in
his pocket. In the meantime, Officer Witherspoon
stopped Davis and patted him down. He found a similar
amount of cash.

       Everything indicated to the officers that this was a
drug deal: the suspicious movements, the hurried depar-
tures, the wads of cash, and the neighborhood itself.
Knowing that guns often accompany drug deals, the of-
ficers decided to search the Jeep for weapons—and to see
if there were any other occupants. Officer Witherspoon
tried to look through the tinted rear window, but it was
too dark. So he opened the already-ajar driver’s door and
saw a handgun wedged between the driver’s seat and the
middle console. At that point, the officers arrested Davis
and Blackshear and placed them in the patrol car.
       The handgun was not the only item in the Jeep. Of-
ficer Witherspoon returned and spotted an opaque shop-
ping bag in the backseat. It was open and contained a
white substance. The officers requested a drug-detection
dog, which alerted to the presence of drugs. The officers
obtained a warrant and recovered ten cell phones, a pair
of binoculars, and two shopping bags with roughly 740
grams of cocaine distributed among nine smaller Ziploc
bags. The cocaine itself was compressed into the shape of
a brick and had a street value over $75,000.

      Davis and Blackshear were charged with pos-

                            5
sessing a controlled substance with intent to distribute
under 21 U.S.C. § 841(a)(1) and with possessing a fire-
arm in furtherance of a drug-trafficking crime under 18
U.S.C. § 924(c). They were also charged with aiding and
abetting under 18 U.S.C. § 2.

       Davis and Blackshear filed a motion to suppress all
evidence from the Jeep. They argued that because the
Jeep’s front driver’s side window was tinted, the officers
could not have seen the alleged reaching, gawking, and
tossing—and so they could not have had any cause for
suspicion in the first place. The District Court inspected
the Jeep and discovered that the window was in fact
tinted. The Court nonetheless denied the suppression
motion. It credited the testimony of the officers who said
that the window had been tint-free on the day of the ar-
rests eight months earlier. It also credited the testimony
of an Enterprise employee who said that neither Enter-
prise nor the manufacturer had tinted the windows and
that since the arrests over fifty people had rented the
Jeep.
       The defendants then pursued separate paths.
Blackshear pled guilty but reserved the right to appeal the
denial of his suppression motion. He received two con-
secutive sixty-month sentences plus four years of super-
vised release. Davis opted for a jury trial. As the trial ap-
proached, the government asked permission to introduce


                             6
Davis’s two prior convictions for possessing cocaine.
The District Court consented, stating that the convictions
were admissible under Federal Rule of Evidence 404(b)
to show that Davis recognized the drugs in the Jeep. At
trial, the jury heard testimony from a range of witnesses,
including Officers Gilliam and Witherspoon; Keith Fes-
tus, the owner of a nearby cell-phone store; and a nar-
cotics expert. The jury ultimately found Davis guilty of
the drug crime but not guilty of the gun crime. He re-
ceived a seventy-eight-month sentence plus four years of
supervised release.

       Davis raises four issues on appeal: the denial of his
suppression motion, the admission of his prior convic-
tions, and two other evidentiary issues. 3

                             II
       Davis’s first argument is that the officers illegally
stopped him after he exited the Jeep. This would make
the cocaine inadmissible as the product of an illegal sei-
zure. “Where a motion to suppress has been denied, we
review the order for clear error as to the underlying facts,
but exercise plenary review as to its legality in the light

      3
        The District Court had jurisdiction under 18
U.S.C. § 3231, and we have final-decision jurisdiction
under 28 U.S.C. § 1291.


                             7
of the court’s properly found facts.” United States v.
Brownlee, 454 F.3d 131, 137 (3d Cir. 2006) (quotation
marks omitted). The District Court rejected Davis’s con-
stitutional argument, and with good reason. 4

       The Fourth Amendment prohibits “unreasonable
searches and seizures.” U.S. Const. amend. IV. The gen-
eral rule is that a search or seizure is unreasonable if the
police lack either probable cause or a warrant—though
courts have created several exceptions to the warrant re-
quirement. See Kentucky v. King, 131 S. Ct. 1849, 1856
(2011) (noting that the ultimate touchstone is “reason-
ableness”). Over the past few decades, the Supreme
Court has created a broad exception to both require-
ments: “an officer may, consistent with the Fourth
Amendment, conduct a brief, investigatory stop when the
officer has a reasonable, articulable suspicion that crimi-
nal activity is afoot.” Illinois v. Wardlow, 528 U.S. 119,
123 (2000) (citing Terry v. Ohio, 392 U.S. 1, 30 (1968)).
This exception also allows officers to search the passen-
ger area of a vehicle without probable cause or a warrant

      4
        Davis has standing to challenge the search of the
Jeep—even though he was a mere passenger—because
his seizure gave the officers a reasonable suspicion to
search inside the Jeep. See United States v. Mosley, 454
F.3d 249, 253 (3d Cir. 2006).


                             8
if they conduct a lawful stop and reasonably believe that
the suspect is dangerous and has a weapon inside. See
Michigan v. Long, 463 U.S. 1032, 1049–50 (1983).

       Davis’s constitutional argument turns on whether
the officers had a reasonable suspicion when they first
stopped him. And that turns on whether the front driver’s
side window was tinted at the time of the arrests—for if it
was, the officers could not have seen through it, and they
would have lacked any reason to suspect an illicit trans-
action. Though the District Court inspected the window
at the suppression hearing and saw that it was tinted, the
Court found that it was not tinted on the day of the arrests
eight months earlier.

       That finding was not clearly erroneous. For one
thing, Officers Gilliam and Witherspoon both testified
that the front driver’s side window, unlike the rear win-
dow, was tint-free when they saw the Jeep. And an En-
terprise employee testified that neither Enterprise nor the
manufacturer had tinted the window and that over fifty
people had rented the car between the arrests and the
hearing. He also said that another renter could have been
responsible for the tint. “Anybody could have put it on.”
J.A. 325. This testimony supports the District Court’s
finding. To be sure, the police took a picture of the Jeep
on the day of the arrests, and the front and rear windows
appear to have the same tint. But the picture was taken at


                             9
night in low lighting. Davis also points to a witness who
testified at the suppression hearing that the window
“probably was a little tinted.” J.A. 385. But the District
Court found that his testimony was not “particularly
credible” for “a number of reasons.” B.A. 6 n.3.

       The record thus contains no evidence that plainly
contradicts the officers’ testimony. And “when the dis-
trict court’s decision is based on testimony that is coher-
ent and plausible, not internally inconsistent and not
contradicted by external evidence, there can almost never
be a finding of clear error.” United States v. Igbonwa,
120 F.3d 437, 441 (3d Cir. 1997). As a result, the District
Court did not clearly err when it found that the window
was tint-free.
       Nor did the District Court err in concluding that
the officers had a reasonable suspicion to stop Davis. The
officers observed odd behavior through the front win-
dow—an exchange, shocked expressions, and tossing
motions. Davis and Blackshear rapidly left the car and
began walking away, the latter failing to close the car
door. And the activity took place in a high-crime area.
The officers thus had a reasonable suspicion that a crime
might be afoot. See Terry, 392 U.S. at 30; Wardlow, 528
U.S. at 124 (recognizing presence in a “high crime area,”
“unprovoked flight,” and “nervous, evasive behavior” as
factors supporting a reasonable suspicion); see also


                            10
United States v. Bonner, 363 F.3d 213, 218 (3d Cir.
2004) (concluding that flight from a traffic stop creates a
reasonable suspicion).

       The officers also had authority to search the Jeep.
The pat downs revealed large wads of cash, suggesting
that Davis and Blackshear were in the middle of a drug
deal. Because drug dealers often carry guns, the officers
had “a reasonable belief based on specific and articulable
facts” that Davis and Blackshear were dangerous and
might have weapons inside the Jeep. Long, 463 U.S. at
1049 (quotation marks omitted); see also United States v.
Arvizu, 534 U.S. 266, 273 (2002). That belief allowed the
officers to search the Jeep for weapons. During the
search, they found something else—cocaine in the
backseat—but they “clearly cannot be required to ignore
the contraband” discovered “while conducting a legiti-
mate Terry search of the interior of the automobile.”
Long, 463 U.S. at 1050. For these reasons, we will affirm
the denial of Davis’s suppression motion.

                            III
       Davis’s second argument is that the District Court
erred in admitting his two prior convictions for pos-
sessing cocaine. We review that decision for an abuse of
discretion. United States v. Butch, 256 F.3d 171, 175 (3d
Cir. 2001) (noting that a decision is an abuse of discre-
tion if “clearly contrary to reason and not justified by the

                            11
evidence” (quotation marks omitted)). Though we have
held that some prior drug convictions are admissible un-
der Federal Rule of Evidence of 404(b), we have never
held that a possession conviction is admissible to show
knowledge or intent in a distribution trial. We decline to
do so today.

                              A

       American courts have long excluded evidence of a
person’s prior bad acts. This tradition reflects a fear that
the jury will place too much weight on past crimes and
prior misdeeds. “[I]t is said to weigh too much with the
jury and to so overpersuade them as to prejudice one with
a bad general record and deny [the accused] a fair op-
portunity to defend against a particular charge.”
Michelson v. United States, 335 U.S. 469, 476 (1948);
see also H. Richard Uviller, Evidence of Character to
Prove Conduct: Illusion, Illogic, and Injustice in the
Courtroom, 130 U. Pa. L. Rev. 845, 884 (1982) (“[A]s
the special conditions of predictive value coalesce, the
potential for prejudice also rises.”). The risk is that jurors
will focus on evidence of prior acts, believing that some-
one with a criminal record cannot change and discount-
ing any evidence to the contrary.

      Over the past two hundred years, the prior-acts
rule has changed much in form but little in function. In
the early days of the common law, courts used an inclu-

                             12
sionary approach: evidence of prior acts was presump-
tively admissible unless it was relevant only to the de-
fendant’s propensity to commit a crime. See Julius Stone,
The Rule of Exclusion of Similar Fact Evidence: Amer-
ica, 51 Harv. L. Rev. 988, 989–90 (1938). In the nine-
teenth century, the rule slowly became exclusionary:
such evidence was presumptively inadmissible unless the
proponent could show that it was relevant to one of sev-
eral specific purposes, such as motive or intent. See id. at
990–93 (concluding that American courts applied this
rule on the mistaken belief that the exclusionary ap-
proach was part of the English common law). But that
trend faded, and courts began to use different ap-
proaches—some inclusionary, some exclusionary. See
United States v. Long, 574 F.2d 761, 765–66 (3d Cir.
1978) (noting the division of authorities). The Federal
Rules of Evidence settled the matter in 1975, establishing
a uniform inclusionary approach. Id.; United States v.
Green, 617 F.3d 233, 244 (3d Cir. 2010). Yet this
change, “like the nineteenth century switch from the in-
clusionary to the exclusionary approach, did not give rise
to any significant change in the admissibility of such evi-
dence.” Kenneth J. Melilli, The Character Evidence Rule
Revisited, 1998 B.Y.U. L. Rev. 1547, 1560.

      The modern approach is set forth in Federal Rule
of Evidence 404(b). “Evidence of a crime, wrong, or
other act is not admissible to prove a person’s character

                            13
in order to show that on a particular occasion the person
acted in accordance with the character.” Fed. R. Evid.
404(b)(1). That principle seems strict, but prior-acts evi-
dence “may be admissible for another purpose, such as
proving motive, opportunity, intent, preparation, plan,
knowledge, identity, absence of mistake, or lack of acci-
dent.” Fed. R. Evid. 404(b)(2). Uncontroversial at the
time of adoption, Rule 404(b) has become the most cited
evidentiary rule on appeal. See Thomas J. Reed, Admit-
ting the Accused’s Criminal History: The Trouble with
Rule 404(b), 78 Temp. L. Rev. 201, 211 (2005).

       The text of Rule 404(b) has led to a four-part test.
Prior-acts evidence is admissible only if it is (1) offered
for a proper purpose under Rule 404(b)(2); (2) relevant to
that purpose; (3) sufficiently probative under the Rule
403 balancing requirement; and (4) accompanied by a
limiting instruction, if requested. See Green, 617 F.3d at
249; see also Huddleston v. United States, 485 U.S. 681,
691–92 (1988) (discussing these four requirements). 5 All

      5
        Rule 404(b) excludes only extrinsic evidence, or
evidence of acts that are not the basis of the current pros-
ecution. It does not exclude intrinsic evidence, which ei-
ther “directly proves” or “facilitate[s]” the charged of-
fense. Green, 617 F.3d at 248–49 (quotation marks
omitted).


                            14
this really means is that such evidence must have a
nonpropensity purpose and satisfy the same relevancy
requirements as any other evidence.

       And yet the relevancy requirements pose problems
of their own in this context. Indeed, the problems are in
many cases insurmountable. See Uviller, 130 U. Pa. L.
Rev. at 878 (“The test of ordinary relevance is often an
insuperable barrier.”). For starters, the prior-acts evi-
dence must be relevant to a proper purpose, and it must
be relevant in a way that avoids any propensity inference.
See United States v. Sampson, 980 F.2d 883, 887 (3d Cir.
1992). Consider a defendant who has been convicted of
manslaughter. In a later assault prosecution, the govern-
ment might want to use the conviction, perhaps to prove
intent. But that use is off limits if the only reason the
conviction is relevant to intent is the inference that be-
cause the defendant has committed manslaughter before,
he must have committed assault now. See id. at 887–88.
In addition, the conviction must be relevant based on
what the factfinder knows about the prior act. So even if
the defendant was convicted of intentional manslaughter,
the conviction will be relevant to intent only if the jury
knows the act was intentional and not reckless or negli-
gent.
      That is why the use of prior-acts evidence requires
care from prosecutors and judges alike. In proffering


                           15
such evidence, the government must explain how it fits
into a chain of inferences—a chain that connects the evi-
dence to a proper purpose, no link of which is a forbid-
den propensity inference. Id. at 887. And then the “dis-
trict court, if it admits the evidence, must in the first in-
stance, rather than the appellate court in retrospect, artic-
ulate reasons why the evidence also goes to show some-
thing other than character.” Id. at 888. The reasoning
should be detailed and on the record; a mere recitation of
the purposes in Rule 404(b)(2) is insufficient.6 Unfortu-
nately, these requirements are “so often honored in the
breach” that they resonate “about as loudly as the prover-
bial tree that no one heard fall in the forest.” United
States v. Givan, 320 F.3d 452, 466 (3d Cir. 2003)
(McKee, J., dissenting).

                             B
      With these principles in mind, we conclude that
Davis’s convictions for possessing cocaine were inad-
missible to prove knowledge or intent in his trial for pos-

      6
        We have affirmed even when a district court’s
analysis was somewhat flimsy—but only when the gov-
ernment had already established a valid chain of infer-
ences. See, e.g., United States v. Lopez, 340 F.3d 169,
173–74 (3d Cir. 2003).


                             16
sessing with intent to distribute. The District Court
abused its discretion by admitting this evidence, and we
will vacate Davis’s conviction.

       Davis was twice convicted of possessing cocaine
under Pennsylvania law—once in 2007 and once in 2008.
The government filed a motion to introduce these con-
victions, advancing a pentad of purposes. J.A. 18 (“This
evidence is relevant to prove the defendant’s plan to,
knowledge of, and intent to distribute and/or possess co-
caine, and absence of mistake or accident.”). To its
credit, the able District Court admitted the convictions as
relevant to a single purpose: “Clearly, evidence of his
prior convictions for possession of crack cocaine makes
it more likely than not that Davis knew that the white
substance in the plastic bag on the back seat of the Jeep
was cocaine.” D.A. 18. The government now argues on
appeal that the evidence also was relevant to intent. See
Appellee Br. at 45.
       Knowledge and intent are indeed proper purposes
under the first part of our Rule 404(b) test. And “[t]here
is no question that, given a proper purpose and reasoning,
drug convictions are admissible in a trial where the de-
fendant is charged with a drug offense.” Sampson, 980
F.2d at 887. We have held, for example, that evidence of
past distribution is relevant to prove knowledge of the
same or different drug in a later distribution trial. E.g.,


                            17
Givan, 320 F.3d at 461 (“The evidence that Givan had
been convicted of distribution of cocaine makes Givan’s
knowledge of the presence of the heroin more probable
than it would have been without the evidence.”); United
States v. Boone, 279 F.3d 163, 187 (3d Cir. 2002) (con-
sidering the defendant’s past cocaine-distribution acts as
evidence that he was not “an ignorant ‘go-fer’”); cf.
United States v. Vega, 285 F.3d 256, 263 (3d Cir. 2002)
(“[E]vidence of Vega’s participation in a prior drug con-
spiracy is probative of his knowledge of, and relationship
with a member of, a later drug conspiracy.”). And we
have held that evidence of past distribution is relevant to
prove intent to distribute in a later distribution trial. E.g.,
United States v. Lee, 573 F.3d 155, 166 (3d Cir. 2009)
(“Lee’s prior drug trafficking conviction was properly
admitted as evidence that Lee intended to distribute any
drugs in his possession.”); Givan, 320 F.3d at 461;
Boone, 279 F.3d at 187. We have even held that evidence
of past distribution is relevant to prove knowledge of a
different drug in a later possession trial. United States v.
Lopez, 340 F.3d 169, 174 (3d Cir. 2003). But we have
never held that a possession conviction is relevant to
prove either knowledge or intent in a distribution trial,
and rightly so.

       1. Knowledge. Possession and distribution are dif-
ferent in ways that matter—something that both the Dis-
trict Court and the government failed to appreciate. As to

                              18
knowledge, one who possesses a drug might not recog-
nize the same drug when prepared for distribution. The
packaging or quantity might be different, and objects in
greater quantities often have an appearance or smell of
their own. Take water, which is transparent by the drop
but blue in the ocean, or powdered sugar, which is floury
on a donut but dense in a bag. In this case, the jury knew
only that Davis had been twice convicted of possessing
cocaine. See Appellee Br. at 19 n.3. The jury knew
nothing of the packaging or quantity that led to those
convictions, so it could not have known whether Davis’s
past helped him to recognize the nearly one kilogram of
cocaine in the Jeep.
       Then there is the problem that the cocaine from
Davis’s past might have been in a different form. Co-
caine is consumable either as a powder or as one of sev-
eral bases, most often crack. See DePierre v. United
States, 131 S. Ct. 2225, 2228–29 (2011). Neither form
particularly resembles the other. As its name suggests,
powder cocaine is a powder—specifically, a salt—that
can be compressed or loose. See David A. Sklansky, Co-
caine, Race, and Equal Protection, 47 Stan. L. Rev.
1283, 1290–91 (1995). On the other hand, crack cocaine
is hard and waxy and often resembles small rocks or
crystals. See id. This distinction matters, and the jury did
not know which form Davis had possessed back in 2007
and 2008. For all the jury knew, the cocaine could have

                            19
been a dash of powder on a golden tray. It could have
been hidden in the lining of a suitcase. Or it could have
been crack cocaine—in crystal form, in liquid form,
rolled up in paper, or stuffed in a syringe. In any of those
instances, Davis’s past would not have helped him to
identify the compressed powder in the backseat.

        The two prior convictions thus fail the second part
of our Rule 404(b) test, the relevancy requirement. See
Fed. R. Evid. 401 (explaining that evidence is relevant if
it is probative of a consequential fact). Based on the bare-
bones stipulation before it, the jury had no way of
knowing whether Davis’s experiences made him any
more likely to recognize the cocaine in the backseat. The
convictions simply were not probative of Davis’s
knowledge. See Givan, 320 F.3d at 466 (McKee, J., dis-
senting) (noting the difficulty when “there is absolutely
nothing on this record that would allow the jury to make
any meaningful or relevant comparison” between past
and present drugs). At best, the convictions had such
limited probative value that they fail the third part of our
test, the balancing requirement. See Fed. R. Evid. 403
(allowing courts to “exclude relevant evidence if its pro-
bative value is substantially outweighed by a danger of
. . . unfair prejudice.”). Either way, the convictions are
inadmissible to prove Davis’s knowledge.

      The government nonetheless urges us to follow


                            20
Lopez and Givan. In Lopez, we held that the defendant’s
participation in a cocaine-distribution conspiracy was
admissible in a possession trial to prove knowledge of
heroin, a different drug altogether. Lopez, 340 F.3d at
174 (“[The conviction] was admissible for the purpose of
rebutting the defendant’s anticipated claim of innocent
association with, and lack of knowledge of, the heroin
found near his bunk.”). And in Givan, we held that the
defendant’s conviction for distributing cocaine was like-
wise admissible to prove knowledge and intent in a her-
oin-distribution trial. Givan, 320 F.3d at 461. These cases
are at the outer bounds of admissibility under Rule
404(b). See David Culberg, Note, The Accused’s Bad
Character: Theory and Practice, 84 Notre Dame L. Rev.
1343, 1358–59 & n.83 (2009) (criticizing Lopez and
Givan). At all events, the two cases are distinguishable
because the defendants had been convicted of dealing co-
caine, and drug dealers presumably have more
knowledge of drugs in general. By contrast, a possession
conviction does not imply a similar level of knowledge.

       2. Intent. Nor does a possession conviction imply
an intent to distribute. Possession and distribution are
distinct acts—far more people use drugs than sell them—
and these acts have different purposes and risks. A prior
conviction for possessing drugs by no means suggests
that the defendant intends to distribute them in the future.
“Acts related to the personal use of a controlled sub-

                            21
stance are of a wholly different order than acts involving
the distribution of a controlled substance. One activity
involves the personal abuse of narcotics.” United States
v. Ono, 918 F.2d 1462, 1465 (9th Cir. 1990). The other
usually involves “the implementation of a commercial
activity for profit.” Id. As a result of these differences,
Davis’s convictions again fail the second part of our Rule
404(b) test.

      In cases such as this, there is an ever-present dan-
ger that jurors will infer that the defendant’s character
made him more likely to sell the drugs in his possession.
But that is precisely the type of inference that Rule
404(b) forbids. Any other conclusion would run the risk
of unraveling the prior-acts rule:
      [I]f the act of possessing or using marijuana
      is to be admissible to prove intent to
      transport and sell marijuana, or, to go even
      further, to prove intent to transport and sell a
      different drug, then there is no reason why
      participation in any drug-related crime could
      not be used to prove intent to engage in any
      other drug-related crime, or why any rob-
      bery could not be used to prove the requisite
      intent with respect to any other robbery. A
      rule allowing such evidence would eviscer-



                            22
      ate almost entirely the character evidence
      rule.

David P. Leonard, The New Wigmore. A Treatise on Evi-
dence: Evidence of Other Misconduct and Similar Events
§ 7.5.2(d); see also Charles Alan Wright & Kenneth W.
Graham, Jr., 22A Federal Practice and Procedure: Evi-
dence § 5242 (2d ed. 2013) (“[T]he routine use of [the
intent] exception [under Rule 404(b)] could easily de-
stroy the exclusionary rule.”).7

      We join other circuits in declaring that a posses-

      7
         Some circuits require prior acts under Rule
404(b) to “meet a threshold level of similarity in order to
be admissible to prove intent” to commit the charged of-
fense. United States v. Long, 328 F.3d 655, 661 (D.C.
Cir. 2003); see also United States v. Foskey, 636 F.2d
517, 524 (D.C. Cir. 1980) (citing cases in Second, Fifth,
and Ninth Circuits for the idea that “[w]hen a prior
criminal act is relied upon to prove intent or knowledge,
similarity between the two events must be shown” (alter-
ation in original and quotation marks omitted)). We need
not adopt that requirement in our Circuit or decide
whether cocaine possession and distribution are suffi-
ciently similar. After all, a past intent to possess drugs
simply is not probative of a future intent to distribute.


                            23
sion conviction is inadmissible to prove intent to distrib-
ute. The Sixth Circuit, for example, held that “possession
of a small quantity of crack cocaine for personal use on
one occasion . . . sheds no light on whether [the defen-
dant] intended to distribute crack cocaine in his posses-
sion on another occasion nearly five months earlier.”
United States v. Haywood, 280 F.3d 715, 721 (6th Cir.
2002). The Seventh and Ninth Circuits have suggested
likewise. See United States v. Santini, 656 F.3d 1075,
1078 (9th Cir. 2011) (holding that prior convictions “for
simple possession” were “not similar to the importation
of marijuana and thus lack[] probative value”); Ono, 918
F.2d at 1465 (distinguishing between possession and dis-
tribution in dicta); United States v. Monzon, 869 F.2d
338, 344 (7th Cir. 1989) (concluding that evidence of the
defendant’s prior marijuana possession was not probative
of his intent to distribute cocaine); United States v.
Marques, 600 F.2d 742, 751 (9th Cir. 1979) (distin-
guishing between “personal use versus resale”); cf.
Enriquez v. United States, 314 F.2d 703, 717 (9th Cir.
1963) (concluding that a trial was unfair because the
court had admitted evidence of marijuana possession to
show intent to sell heroin). But see United States v.
Walsh, 231 F.3d 366, 370-71 (7th Cir. 2000) (allowing
the admission of a possession conviction in a distribution
trial because the conviction involved “distribution
amounts”). Other circuits have reached the opposite re-
sult, but we are not persuaded. See, e.g., United States v.

                            24
Butler, 102 F.3d 1191, 1196 (11th Cir. 1997); United
States v. Logan, 121 F.3d 1172, 1178 (8th Cir. 1997);
United States v. Gadison, 8 F.3d 186, 192 (5th Cir.
1993). We conclude that Davis’s convictions should not
have been before the jury—not as evidence of
knowledge, not as evidence of intent.

       And problems remain. The District Court also
committed two instruction-related errors. First, it did not
provide the requested limiting instruction at the time the
evidence was admitted; it did so only in the final jury
charge. Second, the Court concluded that the convictions
were admissible to prove knowledge, but the jury charge
included a wide list of purposes, allowing the jury to con-
sider the convictions as evidence of “state of mind,
knowledge, or intent,” as well as absence of “accident or
mistake.” J.A. 125–26; see Sampson, 980 F.2d at 889
(“By simply repeating the entire litany of permissible
theories under Rule 404(b), the judge’s instruction gave
the jury inadequate guidance.”). While these errors are
problematic, we would reverse even in their absence. No
instruction could have eliminated the infirmity at the
heart of this case: Davis’s convictions were inadmissible
for any purpose. 8


      8
        The government did not argue the issue of harm-
less error in its brief. Such silence usually means that

                            25
                            IV
      Davis’s two remaining arguments are mere make-
weight. The first is that the District Court improperly
admitted a statement from the government’s expert wit-
ness. The second is that the Court improperly refused to
admit a witness’s prior statement. We review these deci-
sions for an abuse of discretion. See United States v.
Mathis, 264 F.3d 321, 335 (3d Cir. 2001) (applying the
abuse-of-discretion standard to a decision about the ad-
missibility of expert testimony); United States v. Frazier,
469 F.3d 85, 87 (3d Cir. 2006) (applying the same stand-
ard to a decision about the admissibility of a prior con-


harmless error is waived, but we may still consider the
issue depending on “the length and complexity of the
record, whether the harmlessness of the error or errors
found is certain or debatable, and whether a reversal will
result in protracted, costly, and ultimately futile pro-
ceedings in the district court.” United States v.
McLaughlin, 126 F.3d 130, 135 (3d Cir. 1997) (quoting
United States v. Giovannetti, 928 F.2d 225, 227 (7th Cir.
1991)). Here, we refuse to do so because we see no rea-
son “that a reversal will [ ] lead to drawn out proceed-
ings,” and we do not “know with sufficient certainty that
the error was harmless.” United States v. Faulks, 201
F.3d 208, 213 (3d Cir. 2000).


                            26
sistent statement).
        Davis argues that the government’s narcotics ex-
pert, Kenneth Bellis, violated Federal Rule of Evidence
704(b). This Rule bars experts from testifying that the
defendant had the necessary state of mind to commit a
crime—whether it be intent, knowledge, or something
else. 9 Yet the Rule does not bar experts from testifying
about the practices of those in the drug trade. United
States v. Watson, 260 F.3d 301, 308 (3d Cir. 2001). In
fact, such testimony is admissible even if it supports a
conclusion that the defendant had the necessary state of
mind. United States v. Bennett, 161 F.3d 171, 183 (3d
Cir. 1998). The only limitation is that the expert may not
draw the ultimate conclusion for the jury or testify in
such a way that the ultimate conclusion is inevitable. Id.
       Davis objects to the following statement from
Bellis:

      Government:        One further question. If you
                         had that level of cocaine, if you

      9
        Rule 704(b) states, “[i]n a criminal case, an ex-
pert witness must not state an opinion about whether the
defendant did or did not have a mental state or condition
that constitutes an element of the crime charged or of a
defense. Those matters are for the trier of fact alone.”


                           27
                         were a distributor, 740 grams—
                         if you were upper level distrib-
                         utor with 740 grams of cocaine,
                         is it common that you would
                         have persons present?

      Davis’s attorney: Objection.

      The Court:         Objection overruled.

      Government:        Is it common that you would
                         have persons in the presence of
                         that cocaine who did not have a
                         connection to that cocaine?

      Davis’s attorney: Objection.

      The Court:         Overruled.

      Bellis:            Not in my opinion, no.

J.A. 50–51. According to Davis, these questions elicited
Bellis’s opinion on whether Davis intended to distribute
the cocaine in the backseat.
       The major flaw in this argument is that Bellis
merely spoke about common practices. He did not in any
way connect those practices to Davis. This means that
Bellis did not draw the ultimate conclusion for the jury,


                           28
nor did the conclusion inevitably follow from his testi-
mony. United States v. Price, 458 F.3d 202, 212 (3d Cir.
2006) (allowing an expert to say “that in his opinion . . .
drug dealers are very likely to carry guns, and drug buy-
ers almost never do” because the expert “said not a word
about [the defendant’s] mental state” but rather spoke
about “common practices”). Davis’s Rule 704(b) argu-
ment is meritless.

       The same is true of his final argument. Davis as-
serts that the District Court improperly refused to admit a
prior statement from Festus. The statement called into
question the police officers’ accounts, but the Court con-
cluded that it was inadmissible hearsay. See Fed. R. Evid.
802. Federal Rule of Evidence 801(d)(1)(B) defines a
statement as nonhearsay if “[t]he declarant testifies and is
subject to cross-examination about a prior statement, and
the statement . . . is consistent with the declarant’s testi-
mony and is offered to rebut an express or implied charge
that the declarant recently fabricated it or acted from a
recent improper influence or motive in so testifying.”
       Festus’s various accounts are inconsistent at best.
A few months after the arrests, he told Blackshear’s at-
torney in a written statement that the patrol car pulled up
behind the Jeep with its lights flashing. Two months
later, Festus testified in the suppression hearing that the
lights were not flashing. At trial, he returned to his for-


                             29
mer statement that the lights were flashing. 10 The govern-
ment impeached Festus’s trial testimony by introducing
his inconsistent suppression testimony. On redirect, Da-
vis referred Festus to his written statement to Black-
shear’s attorney. See Fed. R. Evid. 612. Davis also asked
the District Court to admit Festus’s written statement as a
prior consistent statement. The Court denied that request.

       As required by Rule 801(d)(1)(B), Festus was
subject to cross-examination and his prior statement—at
least the one he gave to Blackshear’s attorney—was con-
sistent with his trial testimony. But Davis runs into
problems with the requirement that the statement “rebut
an express or implied charge that the declarant recently
fabricated it or acted from a recent improper influence.”
Fed. R. Evid. 801(d)(1)(B). The government never so
much as suggested that Festus’s trial narrative was a re-
cent fabrication. It merely pointed out the inconsistency
between his suppression testimony and his trial testi-
mony. Inconsistency alone is not a charge of recent fabri-
cation; we also require a suggestion of “conscious altera-
tion.” Frazier, 469 F.3d at 89 (“The line between chal-

      10
          Whether the lights were flashing is not relevant
to the crimes or the Fourth Amendment analysis. Yet this
dispute had the potential to call into question the officers’
testimonies.


                             30
lenging credibility or memory and alleging conscious al-
teration can be drawn when a district court determines
whether the cross-examiner’s questions reasonably imply
intent on the part of the witness to fabricate.”); see also
Tome v. United States, 513 U.S. 150, 157 (1995). Absent
that suggestion, Davis’s final argument must fail.

                          ***

       The District Court correctly denied Davis’s sup-
pression motion. We cannot say the same about its deci-
sion to admit Davis’s possession convictions, which were
inadmissible to prove knowledge or intent in a trial for
possession with intent to distribute. We will vacate Da-
vis’s conviction and remand to the District Court.




                            31
