                    FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                       No. 08-50126
                Plaintiff-Appellee,
               v.                                 DC No.
                                              2:06-cr-00353 SJO
KATIE SUE CONTRERAS,
                                                  OPINION
             Defendant-Appellant.
                                         
        Appeal from the United States District Court
           for the Central District of California
         S. James Otero, District Judge, Presiding

                  Argued and Submitted
          November 19, 2008—Pasadena, California

                   Filed September 17, 2009

   Before: Myron H. Bright,* Michael Daly Hawkins, and
            A. Wallace Tashima, Circuit Judges.

                   Opinion by Judge Tashima




   *The Honorable Myron H. Bright, Senior United States Circuit Judge
for the Eighth Circuit, sitting by designation.

                               13485
                 UNITED STATES v. CONTRERAS            13487




                        COUNSEL

Michael Jay Stern, Assistant U.S. Attorney, Los Angeles, Cal-
ifornia, for the plaintiff-appellee.

Thomas W. Kielty, Los Angeles, California, for the
defendant-appellant.


                         OPINION

TASHIMA, Circuit Judge:

  Katie Sue Contreras was convicted for her participation in
a drug-smuggling conspiracy operated out of Ironwood State
Prison, where she worked as a prison cook. She appeals her
13488                UNITED STATES v. CONTRERAS
sentence, arguing that the district court’s two-level enhance-
ment of her offense level for abuse of a position of trust under
United States Sentencing Guideline (“U.S.S.G.”) § 3B1.3 was
in error.

   We agree, and reverse the sentence.1 Contreras’ position at
the prison did not involve any “professional or managerial
discretion,” U.S.S.G. § 3B1.3 cmt. n.1 (2005), and therefore
she did not hold a position of trust under the Guidelines. To
the degree United States v. Hill, 915 F.2d 502 (9th Cir. 1990),
compels a different result, it antedates and conflicts with the
current version of the commentary to the Guidelines, and,
therefore, has been overruled.

          I.   Jurisdiction and Standard of Review

   We have jurisdiction over Contreras’ appeal pursuant to 28
U.S.C. § 1291 and 18 U.S.C. § 3742(a). Because this appeal
turns on an interpretation of the Sentencing Guidelines, it is
a question of law which we review de novo. See United States
v. Holt, 510 F.3d 1007, 1010 (9th Cir. 2007) (“We review de
novo the district court’s interpretation of the United States
Sentencing Guidelines.”).2 “On appeal, we first consider
  1
     Appellant’s motion for leave to file a supplemental brief is therefore
denied as moot.
   2
     In the past, we have reviewed the application of the § 3B1.3 enhance-
ment as a single mixed question of law and fact subject to de novo review.
See, e.g., United States v. Brickey, 289 F.3d 1144, 1153 (9th Cir. 2002).
More recently, following United States v. Booker, 543 U.S. 220 (2005),
and Gall v. United States, 552 U.S. 38 (2007), we held that we generally
“review de novo the district court’s interpretation of the United States
Sentencing Guidelines, review for clear error the district court’s factual
determinations, and review for abuse of discretion the district court’s
applications of the Guidelines to the facts.” United States v. Gomez-Leon,
545 F.3d 777, 782 (9th Cir. 2008) (formatting and citations omitted).
Because we address solely the legal question of the interpretation of the
Guidelines in this case, we need not harmonize these different approaches
here. See generally United States v. Thornton, 511 F.3d 1221, 1227 n.4
(9th Cir. 2008) (noting but declining to resolve the same issue).
                  UNITED STATES v. CONTRERAS               13489
whether the district court committed significant procedural
error . . . .” United States v. Carty, 520 F.3d 984, 993 (9th Cir.
2008) (en banc) (citing Gall v. United States, 128 S. Ct. 586,
597 (2007)). Such significant procedural error includes incor-
rectly calculating the applicable Guidelines range. Id.

                       II.   Background

   Contreras worked as a prison cook at Ironwood State
Prison in Blythe, California. As a prison employee, she was
subject to only a cursory search when she entered the prison
each day, and enjoyed unmonitored contact with inmates in
the prison kitchen.

   Relying on these liberties, Contreras began smuggling
drugs into Ironwood. She hid the drugs in her lunch bag, often
using cans of iced tea outfitted with false compartments to foil
any inspections. Once inside the prison, she distributed the
drugs to inmates involved in the smuggling ring. She was paid
for her efforts, and successfully managed to smuggle heroin,
methamphetamine, and marijuana into Ironwood.

   An independent investigation by the DEA uncovered Con-
treras’ activities, and she eventually pled guilty to one count
of conspiracy to possess with intent to distribute a controlled
substance, in violation of 21 U.S.C. §§ 841(a)(1),
841(b)(1)(A)-(B), 846.

   The district court sentenced Contreras to 41 months’
imprisonment after determining that she had a criminal his-
tory category of I and a total offense level of 22, yielding a
sentencing range of 41 to 51 months. The offense level
included a two-level enhancement for the abuse of a position
of trust, pursuant to U.S.S.G. § 3B1.3. The court applied the
enhancement because Contreras’ “position as an employee
provided her with additional freedom so that she could com-
mit the offense.”
13490                UNITED STATES v. CONTRERAS
  Contreras now appeals the application of the abuse-of-trust
enhancement.

                           III.    Discussion

   [1] The United States Sentencing Guidelines call for a two-
level increase in a defendant’s offense level if “the defendant
abused a position of public or private trust, or used a special
skill, in a manner that significantly facilitated the commission
or concealment of the offense.” U.S.S.G. § 3B1.3. Applying
the enhancement requires a two-part inquiry: First, did the
defendant hold a “position of public or private trust” within
the meaning of the Guidelines? Second, if so, did the position
“significantly facilitate” the commission of the crime? See,
e.g., United States v. Hoskins, 282 F.3d 772, 778 (9th Cir.
2002) (applying test). This case turns solely on the first ques-
tion and requires us to clarify the meaning of a “position of
trust.”

   Prior to 1993, the Sentencing Commission offered little
guidance on this question. The commentary accompanying
§ 3B1.3 provided only that the position “must have contrib-
uted in some substantial way to facilitating the crime and not
merely have provided an opportunity that could as easily have
been afforded to other persons. This adjustment, for example,
would not apply to an embezzlement by an ordinary bank tell-
er.” U.S.S.G. § 3B1.3 cmt. n.1 (1990).3

  [2] Operating under this spare formulation, we held that the
hallmark of a position of trust was “the extent to which the
position provides the freedom to commit a difficult-to-detect
wrong.” Hill, 915 F.2d at 506. The two indicia of such a posi-
  3
    Application notes, such as this one, “are treated as authoritative inter-
pretations of the Sentencing Guidelines, unless they violate the Constitu-
tion or a federal statute or are inconsistent with, or a plainly erroneous
reading of, the Guideline they are meant to interpret.” United States v. Ris-
ing Sun, 522 F.3d 989, 996 (9th Cir. 2008).
                 UNITED STATES v. CONTRERAS               13491
tion are the “inability of the trustor objectively and expedi-
ently to determine the trustee’s honesty” and the “ease with
which the trustee’s activities can be observed.” Id. Applying
these factors, the Hill court found that a truck driver was in
a position of trust when he stole the goods he was entrusted
to transport. Id. at 507.

   In 1993, however, the Sentencing Commission substan-
tially reformulated application note 1 to “better distinguish
cases warranting the enhancement.” U.S.S.G. app. C, amend.
492 (effective Nov. 1, 1993). The version of the commentary
under which Contreras was sentenced now reads:

    “Public or private trust” refers to a position of public
    or private trust characterized by professional or
    managerial discretion (i.e., substantial discretionary
    judgment that is ordinarily given considerable defer-
    ence). Persons holding such positions ordinarily are
    subject to significantly less supervision than employ-
    ees whose responsibilities are primarily non-
    discretionary in nature. For this adjustment to apply,
    the position of public or private trust must have con-
    tributed in some significant way to facilitating the
    commission or concealment of the offense (e.g., by
    making the detection of the offense or the defen-
    dant’s responsibility for the offense more difficult).
    This adjustment, for example, applies in the case of
    an embezzlement of a client’s funds by an attorney
    serving as a guardian, a bank executive’s fraudulent
    loan scheme, or the criminal sexual abuse of a
    patient by a physician under the guise of an exami-
    nation. This adjustment does not apply in the case of
    an embezzlement or theft by an ordinary bank teller
    or hotel clerk because such positions are not charac-
    terized by the above-described factors.

U.S.S.G. § 3B1.3 cmt. n.1 (2005) (emphasis added).
13492             UNITED STATES v. CONTRERAS
   [3] It seems clear that the Hill test should not have survived
the 1993 amendments. Whereas Hill assessed whether a
defendant had the “freedom” to commit a crime without
“quick notice,” 915 F.2d at 506, the commentary instead
emphasizes “professional or managerial discretion.” By the
test’s plain text, the element of discretion — not ease of
detection — is the “decisive factor” in the enhancement.
United States v. Tribble, 206 F.3d 634, 637 (6th Cir. 2000).
It is the “explicit focus” of the Guidelines. United States v.
West, 56 F.3d 216, 219 (D.C. Cir. 1995); see also United
States v. Reccko, 151 F.3d 29, 32 (1st Cir. 1998) (professional
or managerial discretion is “the signature characteristic of a
position of trust”).

   Application note 1 reinforces this conclusion by distin-
guishing various occupations, noting that the enhancement
might apply to an attorney, physician, or bank executive, but
not to an “ordinary bank teller or hotel clerk.” U.S.S.G.
§ 3B1.3 cmt. n.1 (2005). We have previously held that the
listing of professions in the commentary demands “reasoning
by analogy, not just reference to dictionary definitions,” and
that therefore a position of trust refers to “people trained or
employed at a high level.” United States v. Lee, 296 F.3d 792,
798-99 (9th Cir. 2002) (construing the “special skills”
enhancement of § 3B1.3); see also Tribble, 206 F.3d at 637
(“the examples given . . . imply that the inherent nature of the
work itself should naturally convey a substantial degree of
discretion”).

   [4] The new language of the application note “places a sig-
nificant limit on the types of positions subject to the abuse-of-
trust enhancement.” West, 56 F.3d at 220. For example, while
a low-level clerk might have the freedom to act “without
detection” or be “difficult to observe” under Hill, United
States v. Oplinger, 150 F.3d 1061, 1069-70 (9th Cir. 1998)
(applying Hill), such a person plainly lacks “professional or
managerial discretion,” and therefore does not occupy a posi-
tion of trust under the Guidelines. To the degree Hill counsels
                    UNITED STATES v. CONTRERAS                  13493
otherwise, it is incompatible with the revised commentary to
§ 3B1.3.

  Because the 1993 amendments changed the scope of the
enhancement, other circuits have recognized that pre-1993
caselaw is “not particularly helpful” in applying § 3B1.3,
United States v. Jankowski, 194 F.3d 878, 884 n.5 (8th Cir.
1999), and “has no bearing” on the sentencing analysis, Rec-
cko, 151 F.3d at 33. Our court has also looked on pre-1993
caselaw with disfavor, declining to follow other circuits in
extending § 3B1.3 to familial relationships because, in part,
those courts relied on “the older version of the application
note.” United States v. Willard, 230 F.3d 1093, 1097 (9th Cir.
2000).

   Notwithstanding Willard or the 1993 amendments, how-
ever, this court has continued to employ the Hill test for all
business, employment, and professional relationships. See,
e.g., United States v. Peyton, 353 F.3d 1080 (9th Cir. 2003);
Brickey, 289 F.3d 1144; United States v. Medrano, 241 F.3d
740 (9th Cir. 2001); United States v. Velez, 185 F.3d 1048
(9th Cir. 1999); United States v. Isaacson, 155 F.3d 1083 (9th
Cir. 1998); Oplinger, 150 F.3d 1061. None of these cases,
however, analyzed the effect of the amended commentary,
acknowledged that Hill preceded that change, or attempted to
reconcile the two standards.4 The resulting confusion is evi-
dent in our caselaw. Continued use of the Hill test after 1993
has swept up bank tellers, post office clerks, and supply offi-
cers in the enhancement — though none held a position of
“professional or managerial discretion.” See Medrano, 241
F.3d at 746 (“bank teller”); Isaacson, 155 F.3d at 1086 (“head
vault teller”); United States v. Botroff, 1997 U.S. App. LEXIS
  4
    One panel even appears to have labored under the misconception that
Hill was decided in response to the 1993 amendments. See United States
v. McCoy, 1996 WL 495062, at *6-*7 (9th Cir. Aug. 29, 1996) (quoting
1993 amendments and then referring to Hill’s “comprehensive discussion
of this provision”).
13494             UNITED STATES v. CONTRERAS
24665 (9th Cir. Sept. 8, 1997) (“window clerk”); Oplinger,
150 F.3d at 1069 (“supply coordinator”).

   One panel also specifically rejected any exemption for
“low-level” employees, because the requirement that a defen-
dant exercise a “special level of responsibility or seniority” to
be in a position of trust “has no basis in the language of the
Guidelines.” Oplinger, 150 F.3d at 1069. The fact is, how-
ever, that the language of the Guidelines contains exactly such
a requirement. Thus, we conclude that the Oplinger panel,
like the others to apply Hill since 1993, simply failed to rec-
ognize or address the change in the law.

   We recognize the general rule that a subsequent panel of
this court cannot overrule a prior panel. See, e.g., United
States v. Gay, 967 F.2d 322, 327 (9th Cir. 1992). Circuit pre-
cedent, however, loses its binding force when an “en banc
decision, Supreme Court decision, or subsequent legislation
undermines” that precedent. Baker v. Delta Air Lines, Inc., 6
F.3d 632, 637 (9th Cir. 1993). Because the commentary to the
Guidelines is “authoritative,” Stinson v. United States, 508
U.S. 36, 38 (1993), the first panel to apply § 3B1.3 after the
1993 amendments should have explicitly reconciled the new
commentary with Hill — or else discarded Hill entirely;
instead, it simply overlooked the 1993 amendments. No panel
has yet addressed § 3B1.3 since the 1993 amendments.
Instead, all subsequent panels have ignored the obvious ten-
sion between the 1993 amendments and Hill, without address-
ing or analyzing the change in the law.

   In these circumstances, appellate courts have held, for
example, that a prior panel that does not address or acknowl-
edge binding Supreme Court authority does not bind a later
panel, which must follow the Supreme Court decision, not the
circuit precedent. See, e.g., Atl. Thermoplastics Co. v. Faytex
Corp., 970 F.2d 834, 838 n.2 (Fed. Cir. 1992) (“A decision
that fails to consider Supreme Court precedent does not con-
trol if the court determines that the prior panel would have
                    UNITED STATES v. CONTRERAS                   13495
reached a different conclusion if it had considered controlling
precedent”), reh’g en banc denied, 974 F.2d 1279 (Fed. Cir.
1992); Tucker v. Phyfer, 819 F.2d 1030, 1035 n.7 (11th Cir.
1987) (prior circuit decision that “decided the case without
any reference” to controlling Supreme Court opinions did not
bind later panel) (questioned by Smith v. GTE Corp., 236 F.3d
1292, 1302-03 (11th Cir. 2001)); Wilson v. Taylor, 658 F.2d
1021, 1035 (5th Cir. Unit B Oct. 1981) (subsequent panel not
bound by prior decision that “did not purport to interpret” a
binding Supreme Court decision). Cf. Miller v. Gammie, 335
F.3d 889, 900 (9th Cir. 2003) (en banc) (recognizing that
where intervening authority, there Supreme Court precedent,
“is clearly irreconcilable with our prior circuit authority,” “a
three-judge panel . . . should consider [itself] bound by the
intervening higher authority and reject the prior opinion of
this court as having been effectively overruled”).

  We face a similar situation. No panel has attempted to rec-
oncile Hill with the 1993 amendments, or recognized that Hill
was formulated under language that has since been deleted
entirely from the Guidelines.

   To be sure, some panels have used both Hill and the “pro-
fessional or managerial discretion” standard to analyze the
application of the enhancement, typically because both tests
pointed in the same direction. See, e.g., Hoskins, 282 F.3d at
778-79 (noting that a store security guard who needed permis-
sion to take a bathroom break lacked any “professional or
managerial discretion,” and also that the “two Hill indicia are
noticeably absent”); Brickey, 289 F.3d at 1154-55 (applying
enhancement to border guard who had “wide discretion in
deciding whom to admit into the United States” and whose
smuggling would be difficult to detect by the government
under Hill).5 We cannot reconcile the two tests in this case,
however, because the two are at loggerheads.
  5
   We note, however, that merely having “discretion” in one’s job is not
the touchstone of a position of trust; the defendant must have “profes-
13496                 UNITED STATES v. CONTRERAS
   Without a doubt, Contreras’ position at the prison gave her
the “freedom to commit a difficult-to-detect wrong,” and she
therefore occupied a position of trust, as construed by Hill.
See 915 F.2d at 506. As a prison cook, she enjoyed unmoni-
tored contact with the inmates, and was not thoroughly
searched upon entering the prison. Her job helped conceal the
crime — the touchstone inquiry under Hill.

   [5] Equally certain, however, is the fact that Contreras was
not a supervisor, professional, or manager. She held no signif-
icant position of authority at Ironwood and exercised no “pro-
fessional or managerial discretion.” Her position was far
closer to — if not almost identical with — that of an ordinary
bank teller or hotel clerk, persons the application note specifi-
cally instructs are not subject to the enhancement.

   [6] This case is on all fours with United States v. Long, 122
F.3d 1360 (11th Cir. 1997), in which the court reversed a
position-of-trust enhancement for a prison cook, because the
fact that the defendant “could enter the prison without being
searched” did not demonstrate the necessary discretion, and
because to hold otherwise “would extend [§ 3B1.3] to virtu-
ally every employment situation.” Id. at 1366. We agree with
the reasoning of Long.

  [7] We conclude that to the extent Hill conflicts with appli-
cation note 1 of § 3B1.3, Hill is no longer good law; it has
been overruled by the 1993 amendments to § 3B1.3’s com-
mentary.

sional or managerial discretion.” U.S.S.G. § 3B1.3 cmt. n.1 (2005)
(emphasis added). This means the defendant is a “ ‘professional’ or ‘man-
ager’ who, because of his or her special knowledge, expertise, or manage-
rial authority, is trusted to exercise ‘substantial discretionary judgment that
is ordinarily given considerable deference.’ ” West, 56 F.3d at 220 (citing
application note 1); see also United States v. Technic Servs., Inc., 314 F.3d
1031, 1056 (9th Cir. 2002) (B. Fletcher, J., dissenting in part) (“To deter-
mine the meaning of a term in the Guidelines, we apply principles of statu-
tory construction, and except in rare instances, we give terms their plain
meaning.”).
                 UNITED STATES v. CONTRERAS             13497
                      IV.   Conclusion

  For the reasons set forth above, we reverse the sentence and
remand for resentencing without imposition of the § 3B1.3
enhancement.

  REVERSED and REMANDED.
