                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


UNITED STATES OF AMERICA,                No. 13-10048
                Plaintiff-Appellee,
                                            D.C. No.
                 v.                      2:10-cr-00564-
                                          LDG-VCF-1
MATTHEW STEWART,
           Defendant-Appellant.            OPINION


      Appeal from the United States District Court
               for the District of Nevada
       Lloyd D. George, District Judge, Presiding

                Argued and Submitted
      March 11, 2014—San Francisco, California

                  Filed July 31, 2014

     Before: Sidney R. Thomas, Raymond C. Fisher
         and Marsha S. Berzon, Circuit Judges.

               Opinion by Judge Fisher
2                 UNITED STATES V. STEWART

                           SUMMARY*


                          Criminal Law

    Affirming a sentence for distributing a controlled
substance, the panel reaffirmed this court’s holding that
because 18 U.S.C. § 944(h) does not limit career offender
status under the Sentencing Guidelines to defendants with
two predicate federal convictions, the Sentencing
Commission did not exceed the scope of its delegated
authority by including prior state convictions as an additional
basis for career offender status.

    The panel also held that the district court was mistaken
about the impact of the purity of the controlled substance, but
that the defendant’s sentence was nonetheless reasonable
under the totality of the circumstances.


                            COUNSEL

Jeremy M. Delicino, Salt Lake City, Utah, for Defendant-
Appellant.

Peter S. Levitt (argued), Assistant United States Attorney,
Elizabeth O. White, Appellate Chief, Daniel G. Bogden,
United States Attorney, Las Vegas, Nevada, for Plaintiff-
Appellee.




  *
    This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                UNITED STATES V. STEWART                     3

                         OPINION

FISHER, Circuit Judge:

     Matthew Stewart pled guilty to two counts of distributing
a controlled substance in violation of 21 U.S.C. § 841(a)(1).
Because he had two prior state felony convictions for
controlled substance offenses, the district court sentenced him
as a career offender. See United States Sentencing Guidelines
Manual (U.S.S.G.) §§ 4B1.1, 4B1.2. Stewart appeals his
sentence, arguing that the Sentencing Commission exceeded
its statutory authority under 28 U.S.C. § 994(h) by including
state convictions as predicate offenses for purposes of
defining a career offender. He further contends his sentence
is substantively unreasonable because of the very low purity
of the controlled substance he sold and the career offender
guidelines’ over-representation of his criminal history. We
once again hold that the Commission’s career offender
guidelines are a permissible interpretation of the relevant
statutes. See United States v. Rivera, 996 F.2d 993, 994–97
(9th Cir. 1993). We further conclude that the district court
was mistaken about the impact of the purity of the controlled
substance, but that Stewart’s sentence was nonetheless
reasonable under the totality of the circumstances. We
therefore affirm.

                              I

     In July 2010, federal Drug Enforcement Agency (DEA)
officers learned from a confidential source that Stewart was
potentially a “gallon producer” and distributor of gamma-
hydroxybutyric acid (GHB). Acting on this tip, the DEA
initiated a series of controlled buys of GHB from Stewart.
On three separate occasions over the next several months,
4               UNITED STATES V. STEWART

Stewart sold water bottles – each containing a detectable
amount of GHB dissolved in water – to an undercover officer:
a single water bottle for $160; eight water bottles for $1,700;
and 16 water bottles containing approximately two gallons of
total liquid for an unknown price. Agents arrested Stewart
and conducted a search of his residence, where they seized
additional water bottles containing liquid with a detectable
amount of GHB. Laboratory testing on all of the seized
bottles confirmed the presence of GHB in 11,359 milliliters
of total liquid, or about three gallons.

    Stewart pled guilty to two counts of distributing a
controlled substance under 21 U.S.C § 841(a)(1). Absent
application of the career offender guidelines, Stewart would
have had a criminal history category of III. But because
Stewart had two prior state felony convictions for drug
distribution, he qualified as a career offender with an
automatic criminal history category of VI. See U.S.S.G.
§ 4B1.1(a)–(b). Stewart’s first conviction was for the sale of
ecstasy tablets in 2002, and his second was for the sale of
cocaine in 2005. Based on the 20-year statutory maximum
term of imprisonment for the offense to which Stewart pled
guilty, 21 U.S.C. § 841(b)(1)(C), the career offender
guidelines reset Stewart’s offense level to 32, see U.S.S.G.
§ 4B1.1(b)(3). Applying a criminal history category of VI
and a three-level downward adjustment for acceptance of
responsibility, the district court calculated a guidelines range
of 151 to 188 months of imprisonment. Although the district
court found that a sentence within this range would be
appropriate, it nonetheless sentenced Stewart to 120 months’
imprisonment. Stewart timely appealed his sentence.
                UNITED STATES V. STEWART                    5

                             II

    The Sentencing Commission’s authority for the career
offender guidelines rests on 28 U.S.C. § 994. Section 994(h)
directs the Commission to “assure” that the guidelines specify
a sentence “at or near” the statutory maximum for a defendant
who: (1) has been convicted of a crime of violence or a
controlled substance offense; and (2) has two or more prior
felony convictions, each of which is a crime of violence or a
controlled substance offense. See 28 U.S.C. § 994(h).

    Carrying out this mandate, the Commission promulgated
the career offender guidelines, which categorize an adult
defendant as a “career offender” when the defendant (1) is
convicted of “a felony that is either a crime of violence or a
controlled substance offense” and (2) “has at least two prior
felony convictions of either a crime of violence or a
controlled substance offense.” U.S.S.G. § 4B1.1(a); see also
United States v. Mitchell, 624 F.3d 1023, 1026 (9th Cir.
2010). The guidelines define a “controlled substance
offense” as “an offense under federal or state law” that
“prohibits the manufacture, import, export, distribution, or
dispensing of a controlled substance,” or possession of a
controlled substance with the intent to do the same. U.S.S.G.
§ 4B1.2(b).

    Stewart acknowledges that he was properly categorized as
a career offender under the guidelines, based on his federal
conviction for distributing GHB and his two prior state drug
distribution convictions. See U.S.S.G. §§ 4B1.1, 4B1.2. He
argues, however, that the career offender guidelines are
invalid because they conflict with the plain language of
§ 994(h), which he interprets as requiring a guidelines
sentence at or near the statutory maximum only for
6               UNITED STATES V. STEWART

defendants with two prior federal, not state, drug trafficking
convictions. His argument relies on the language of § 994(h),
which specifies career offender treatment only for a defendant
who has two or more previous convictions for a controlled
substance offense “described in” certain federal controlled
substances statutes:

       The Commission shall assure that the
       guidelines specify a sentence to a term of
       imprisonment at or near the maximum term
       authorized for categories of defendants in
       which the defendant is eighteen years old or
       older and –

       (1) has been convicted of a felony that is –

           (A) a crime of violence; or

           (B) an offense described in section 401 of
           the Controlled Substances Act (21 U.S.C.
           841), sections 1002(a), 1005, and 1009 of
           the Controlled Substances Import and
           Export Act (21 U.S.C. 952(a), 955, and
           959), and chapter 705 of title 46; and

       (2) has previously been convicted of two or
       more prior felonies, each of which is –

           (A) a crime of violence; or

           (B) an offense described in section 401 of
           the Controlled Substances Act (21 U.S.C.
           841), sections 1002(a), 1005, and 1009 of
           the Controlled Substances Import and
                UNITED STATES V. STEWART                    7

           Export Act (21 U.S.C. 952(a), 955, and
           959), and chapter 705 of title 46.

28 U.S.C. § 994(h). On the strength of this language, Stewart
argues that the Commission exceeded its authority when it
adopted guidelines imposing career offender status for
previous state controlled substance convictions.

    We rejected this very argument in United States v. Rivera,
996 F.2d 993, 994–97 (9th Cir. 1993), and we now reaffirm
Rivera’s continuing validity. In Rivera, we held that the
guidelines were a “sufficiently reasonable” interpretation of
the ambiguous language of § 994(h), because this section is
not limited to predicate offenses under federal law but
extends to conduct involving controlled substances that could
have been charged federally. See id. We further noted that
the career offender guidelines were consistent with Congress’
intent to punish repeat drug traffickers regardless of whether
their predicate convictions were state or federal. See id. at
996.

    Stewart argues that Rivera cannot be reconciled with the
Supreme Court’s subsequent decision in United States v.
LaBonte, 520 U.S. 751 (1997), because Rivera applied an
erroneous standard of review. We do not agree that LaBonte
undermines Rivera’s holding. LaBonte held that the
Commission’s definition of “offense statutory maximum” in
§ 4B1.1 was invalid because it was “at odds with the plain
language” and “ordinary meaning” of 28 U.S.C. § 994(h).
520 U.S. at 756, 757 (quoting Moskal v. United States,
498 U.S. 103, 108 (1990)) (internal quotation marks omitted).
The Court noted that “Congress has delegated to the
Commission ‘significant discretion in formulating’” the
sentencing guidelines, but the Commission’s promulgations
8               UNITED STATES V. STEWART

must nonetheless “bow to the specific directives of
Congress.” Id. at 757 (quoting Mistretta v. United States,
488 U.S. 361, 377 (1989)); see also United States v. Tercero,
734 F.3d 979, 982 (9th Cir. 2013) (explaining that LaBonte
invalidated a guidelines provision as being “in direct conflict”
with the authorizing statute).

    Admittedly, we applied a different standard of review in
Rivera, asking “whether the Sentencing Guideline [was]
‘sufficiently reasonable’ in light of the congressional
directive to the Commission,” 996 F.2d at 994, rather than
whether there was a direct conflict with the statute.
Nevertheless, our inquiry was consistent with the analysis
applied in LaBonte because a guideline that constitutes a
“sufficiently reasonable” interpretation of the enabling statute
cannot be in direct conflict with the statute’s plain mandate.

    In Rivera, we first found § 994(h) to be ambiguous,
because “it is not at all clear that Congress intended to
exclude state [controlled substance] convictions” as predicate
offenses triggering career offender status. 996 F.2d at
995–96. Only then did we conclude that the Commission’s
interpretation was a sufficiently reasonable implementation
of congressional intent. See id. Although § 994(h) could be
interpreted as Stewart prefers – that career offender status
does not depend on prior state felony convictions – there is no
direct conflict between the Commission’s contrary
interpretation and section 994(h)’s plain language. See id. at
995; see also United States v. Beasley, 12 F.3d 280, 283 (1st
Cir. 1993) (holding that a “literal reading” of this section
supports the Commission’s interpretation); United States v.
Whyte, 892 F.2d 1170, 1174 (3d Cir. 1989) (holding that the
Commission’s interpretation “is authorized, if not required,
by section 994(h)”). Because Rivera is not “clearly
                   UNITED STATES V. STEWART                             9

irreconcilable with the reasoning or theory” of LaBonte, we
remain bound by its holding. Miller v. Gammie, 335 F.3d
889, 893 (9th Cir. 2003) (en banc).1

    Even if we were free to reconsider Rivera, we would
reach the same result. As we explained there, “the language
of § 994(h) suggests that the predicate drug convictions need
not be federal as long as they are for conduct that could have
been charged federally.” 996 F.2d at 996 (citing Whyte,
892 F.2d at 1174). We reasoned that:

         Section 994(h)(2)(B) provides that offenses
         “described in” the federal statutes listed in
         that subsection serve as predicates for career
         offender status. If Congress had intended
         only federal offenses to serve as predicates for
         career offender status, it could have done so
         by providing that only “convictions obtained
         under” the federal statutes would be the basis
         for career offender status. The fact that
         Congress used the words “described in”
         indicates the focus is not upon whether the
         predicate offense is federal or state; rather, the
         focus is upon the type of conduct involved.


    1
      Since LaBonte, we have consistently upheld the sentences of
defendants who were classified as career offenders based on their prior
convictions for state felony controlled substance offenses, without
commenting on the validity of the guidelines. See, e.g., United States v.
Lee, 704 F.3d 785, 788–92 (9th Cir. 2012); Mitchell, 624 F.3d at 1027;
United States v. Charles, 581 F.3d 927, 934 (9th Cir. 2009); United States
v. Crawford, 520 F.3d 1072, 1077–80 (9th Cir. 2008); United States v.
Sandoval-Venegas, 292 F.3d 1101, 1106–07 (9th Cir. 2002). This
consistent enforcement of the guidelines is a further indication that
LaBonte did not disturb our holding in Rivera.
10                 UNITED STATES V. STEWART

Id.2 Thus, the career offender guidelines, which include
controlled substance offenses under both federal and state law
as qualifying predicate offenses, are “consistent with the type
of conduct Congress intended to penalize” in § 994(h). Id.
(emphasis added). Every other circuit to consider this
question agrees. See United States v. Jemine, 555 F. App’x
624, 625 (7th Cir. 2014); United States v. Najar, 225 F.3d
660, 2000 WL 799331, at *3 (6th Cir. 2000) (unpublished
table decision); United States v. Gonsalves, 121 F.3d 1416,
1417–19 (11th Cir. 1997); United States v. Brown, 23 F.3d
839, 840–41 (4th Cir. 1994), abrogated on other grounds by
Koon v. United States, 518 U.S. 81 (1996); United States v.
Consuegra, 22 F.3d 788, 789–90 (8th Cir. 1994); Beasley,
12 F.3d at 282–84; Whyte, 892 F.2d at 1174.

    Our post-Rivera decision in United States v. Heim,
15 F.3d 830 (9th Cir. 1994), offers a further reason for
rejecting Stewart’s challenge. We stated there that Congress
did not intend § 994(h) to establish “an exhaustive list . . . of
[the] types of cases in which terms at or close to authorized
maxima should be specified.” Id. at 832 (quoting S. Rep. No.
98-225 (1983)) (internal quotation marks omitted). On the
contrary, § 994(h) establishes only “the minimum obligation
of the Commission,” United States v. Damerville, 27 F.3d
254, 257 (7th Cir. 1994), or “the irreducible minimum that
the Commission must do by way of a career offender
guideline,” United States v. Piper, 35 F.3d 611, 618 (1st Cir.


 2
   Section 994(h) “provides a narrow list of drug offenses that require the
‘at or near the maximum’ career offender treatment, including distribution
under [21 U.S.C.] § 841, importation of certain controlled substances
under 21 U.S.C. § 952(a), and manufacturing and distributing on board
vessels under 46 U.S.C. § 70503.” United States v. Knox, 573 F.3d 441,
448 (7th Cir. 2009).
                UNITED STATES V. STEWART                     11

1994). Under its extensive statutory authority to develop the
guidelines, see 28 U.S.C. § 994(a)–(f); United States v.
Mendoza-Figueroa, 65 F.3d 691, 692 (8th Cir. 1995) (en
banc), the Commission may go beyond the minimum
requirements of § 994(h), so long as the resulting guidelines
do not conflict with any “specific directives of Congress,”
LaBonte, 520 U.S. at 757. Thus, because section 994(h) does
not limit career offender status to defendants with two
predicate federal convictions, the Commission did not exceed
the scope of its delegated authority by including prior state
convictions as an additional basis for career offender status.
Cf. Heim, 15 F.3d at 832.

                              III

    Stewart also challenges the substantive reasonableness of
his 120-month sentence. Neither party challenges the district
court’s sentencing procedure, so we evaluate the substantive
reasonableness of Stewart’s sentence under an abuse of
discretion standard. See United States v. Edwards, 595 F.3d
1004, 1014 (9th Cir. 2010). We consider the totality of the
circumstances, including the degree of the court’s variance
from the guidelines sentencing range and its discretionary
weighing of the factors set forth in 18 U.S.C. § 3553(a). See
United States v. Carty, 520 F.3d 984, 993 (9th Cir. 2008) (en
banc). “[A]lthough the ‘Guidelines should be the starting
point and the initial benchmark,’ district courts may impose
sentences within statutory limits based on appropriate
consideration of all of the factors listed in § 3553(a), subject
to appellate review for ‘reasonableness.’” Pepper v. United
States, 131 S. Ct. 1229, 1241 (2011) (quoting United States
v. Gall, 552 U.S. 38, 49–51 (2007)). “[W]e may reverse if,
upon reviewing the record, we have a definite and firm
conviction that the district court committed a clear error of
12                 UNITED STATES V. STEWART

judgment in the conclusion it reached upon weighing the
relevant factors.” United States v. Ressam, 679 F.3d 1069,
1087 (9th Cir. 2012) (en banc) (quoting United States v.
Amezcua-Vasquez, 567 F.3d 1050, 1055 (9th Cir. 2009))
(internal quotation marks omitted).

    There is no dispute that Stewart’s third drug distribution
conviction qualified him as a career offender under the
guidelines. As a career offender, Stewart’s offense level was
set by reference to the 20-year statutory maximum penalty for
distributing GHB, a penalty that applies regardless of the
quantity or purity of GHB involved in the offense. See
U.S.S.G. § 4B1.1(b)(3); 21 U.S.C. § 841(b)(1)(C).3 Based on
this offense level and the criminal history category of VI
imposed by the career offender guidelines, the district court
correctly calculated Stewart’s guidelines range as 151 to 188
months’ imprisonment, after a three-level downward
adjustment for acceptance of responsibility.

    Acknowledging its authority to depart below this
recommended sentencing range, the court imposed a 120-
month sentence, 31 months below the low end of the
applicable career offender guidelines range. Stewart


 3
   In this respect, GHB is different from other controlled substances. For
many controlled substances, including marijuana, cocaine,
methamphetamine and heroin, the statutory maximum is tied to the
quantity of drugs involved in the offense.               See 21 U.S.C.
§ 841(b)(1)(A)–(B), (D). As a consequence, the offense level under the
career offender guidelines for offenses involving these drugs may increase
as drug quantity increases. See U.S.S.G. § 4B1.1(b). For GHB, however,
there is a single statutory maximum of 20 years regardless of the quantity
of GHB involved. Thus, for purposes of determining Stewart’s offense
level under the career offender guidelines, the quantity of GHB involved
in his offense is immaterial.
                UNITED STATES V. STEWART                     13

nevertheless argues that his sentence is unreasonable because
of (1) the very low purity of the GHB mixture involved in the
offense; (2) the career offender guidelines’ over-
representation of the seriousness of his criminal history and
risk of recidivism; and (3) the systemic shortcomings of the
career offender provisions as applied in any case, including
his.

    The district court explicitly considered and rejected
Stewart’s arguments in light of the guidelines and the
§ 3553(a) factors, making an “individualized assessment
based on the facts presented.” Gall, 552 U.S. at 50. As we
shall explain, the district court was likely mistaken in its
assumption about the significance of the GHB mixture’s
purity under the non-career offender guidelines. Nonetheless,
we affirm the reasonableness of Stewart’s sentence under the
totality of the circumstances. Stewart was indisputably a
career offender, and the district court correctly calculated his
applicable guidelines range and otherwise evaluated the
relevant factors in sentencing him to a below-guidelines
sentence.

   A. Purity or Concentration of GHB Mixture

    Stewart contends that the extremely low purity of the
GHB mixture warranted a significant variance from the career
offender guidelines, and that even a below-guideline, 120-
month sentence was unreasonable. According to laboratory
testing, one sample of the liquid Stewart sold contained
0.055% pure GHB. Another sample contained just 0.046%
GHB. When used for approved therapeutic purposes, GHB
is distributed in a solution of 50% purity – over 900 times
more concentrated than the most concentrated mixture
Stewart sold to the undercover agent. Stated another way,
14                 UNITED STATES V. STEWART

Stewart sold about three gallons of water that contained
roughly five to six total grams of dissolved GHB. This is the
equivalent of only a single prescribed dose of GHB, or a
maximum of six “doses” for illicit purposes.4

     The district court accepted Stewart’s evidence of low
purity but rejected his argument for a variance. Agreeing
with the presentence report (PSR), it concluded that absent
the career offender provisions, Stewart would be sentenced
based on the entire 11 liters of the GHB mixture he sold
without regard to purity, yielding a guidelines range of 46 to
57 months.5 Because the district court viewed purity as
irrelevant for determining drug quantity under the guidelines,
it found that the very low purity of the GHB mixture was
irrelevant to any variance from the career offender provisions.

    We disagree with the district court’s conclusion that
Stewart’s non-career-offender sentencing range would have
been based on 11 liters of GHB. First, purity or dilution is a
relevant consideration for crafting a sentence that is
“sufficient, but not greater than necessary,” under § 3553(a).
Just as an upward variance or departure may be justified

 4
   See U.S. Dep’t of Justice, Drug Enforcement Admin., Drugs of Abuse:
A DEA Resource Guide 54 (2011 ed.) (stating that the average dose of
GHB when illicitly used is approximately one to five grams), available at
http://www.justice.gov/dea/pr/multimedia-library/publications/drug_of_
abuse.pdf.
 5
    Under the guidelines, one milliliter or gram of GHB is the equivalent
of 8.8 grams of marijuana for purposes of calculating a base offense level.
See U.S.S.G. § 2D1.1 cmt. n.8(D). Thus, without accounting for purity,
the 11,359 milliliters of the GHB mixture Stewart distributed yields an
offense level of 24, and after a reduction for acceptance of responsibility,
a guidelines range of 46 to 57 months’ imprisonment based on his
category III criminal history.
                UNITED STATES V. STEWART                     15

based on the unusually high purity of a drug, see U.S.S.G.
§ 2D1.1 cmt. n.26(C), a downward variance for a mixture of
unusually low purity may be justified in appropriate
circumstances to better reflect the nature and seriousness of
the offense, see 18 U.S.C. § 3553(a)(1)–(2).

    Second, the district court was likely mistaken in its
assumption about the significance of the GHB mixture’s
purity under the non-career offender guidelines. Typically,
drug quantity under the guidelines includes the entire weight
or volume of any mixture containing a detectable amount of
controlled substance, without regard to purity or
concentration. See U.S.S.G. § 2D1.1(c) n.(A). For the
weight or volume of a mixture to be considered in its entirety,
however, it first must be useable as an illicit drug. See United
States v. Sprague, 135 F.3d 1301, 1305 (9th Cir. 1998)
(holding that under the “marketable material approach,” “the
weight of an unusable material mixed with a controlled
substance should not be included in the weight for
sentencing”). Therefore, a defendant’s drug quantity “does
not include materials that must be separated from the
controlled substance before the controlled substance can be
used,” whether or not the materials can in fact be separated.
U.S.S.G. § 2D1.1 cmt. n.1; see also United States v. Byfield,
391 F.3d 277, 280 (D.C. Cir. 2004) (“[U]sability [is] essential
for calculating the weight of a drug quantity for § 2D1.1
sentencing purposes.”); United States v. Stewart, 361 F.3d
373, 377 (7th Cir. 2004) (“[O]nly usable or consumable
mixtures or substances are included in the drug quantity for
sentencing purposes.”).

   We have explained that “packaging material” and “the
weight of waste washings in a mixture containing only trace
amounts of a controlled substance” are two examples of
16              UNITED STATES V. STEWART

substances that must “be separated from the [controlled
substance] before it could be used.” Sprague, 135 F.3d at
1305–06. “On the other hand, the weight of a consumable
cutting or diluting agent used to increase the total amount of
a marketable controlled substance would not be excluded as
it need not be separated to render the drug useable.” Id. at
1305 (emphasis added).

    Although we have not located any case specifically
addressing highly diluted GHB, courts have addressed
analogous circumstances for other controlled substances. In
United States v. Robins, 967 F.2d 1387 (9th Cir. 1992), for
example, we held that the weight of cornmeal mixed with
cocaine should not be used in determining the base offense
level, because the 2,779 grams of cornmeal at issue “had to
be separated from the [one-tenth of a gram of] cocaine before
the cocaine could be effectively used.” Id. at 1388–89. The
cornmeal was “the functional equivalent of packaging
material,” because the cornmeal-cocaine mixture could not be
used without separating out the drug first. Id. at 1389. As did
Stewart here, the defendant in Robins attempted to defraud an
undercover agent by masking the very small quantity of a
controlled substance actually being sold. Id. at 1388.

    When confronted with an unuseable or unmarketable
mixture, “rather than weighing everything, [a district court
should] . . . include only the amount of usable or consumable
substances, or the amount of drug that the defendant could
have extracted from something that is unusable at the time of
arrest.” Stewart, 361 F.3d at 378–79 (internal citations
omitted). This logic has been applied to an “unmarketable”
mixture containing over 1000 grams of sugar and only 10
grams of cocaine, see United States v. Jackson, 115 F.3d 843,
848–49 (11th Cir. 1997); a mixture containing
                UNITED STATES V. STEWART                     17

methamphetamine and other substances that had to be
evaporated or filtered out before the drug could be used, see
Sprague, 135 F.3d at 1306; a solution of waste water
containing a trace amount of cocaine, see United States v.
Johnson, 999 F.2d 1192, 1196–97 (7th Cir. 1993); and large
quantities of cocaine diluted in wine or liqueur, see United
States v. Palacios-Molina, 7 F.3d 49, 54 (5th Cir. 1993);
United States v. Acosta, 963 F.2d 551, 554–56 (2d Cir. 1992).
But see United States v. Berroa-Medrano, 303 F.3d 277,
283–84 (3d Cir. 2002) (holding that a defendant who agreed
to sell a package containing one kilogram of common heroin
cutting agents and only a trace amount of heroin is
accountable for the entire weight of the package). This is in
contrast to those cases where, despite dilution or
contamination, the controlled substance mixture “was ready
for sale and for use as it was.” United States v. Coleman,
166 F.3d 428, 432 (2d Cir. 1999) (emphasis omitted).

    Thus, when GHB is dissolved in water at a useable
concentration, the entire volume of the GHB mixture must be
considered in determining drug quantity, because the water
serves only as a dilutant of the GHB, facilitating its use and
distribution. See Sprague, 135 F.3d at 1305. On the other
hand, when reliable scientific evidence shows that GHB is
diluted past the point of usability, the drug quantity should be
based on an approximation of the amount of usable GHB
mixture dissolved in the total liquid. See U.S.S.G. § 2D1.1
cmt. n.1. The water is not merely a dilutant in this latter
circumstance, but a “material[] that must be separated from
the [GHB] before the [GHB] can be used.” Id. An unuseable
GHB mixture “[does] not constitute ‘a drug product moving
through the chain of distribution in the manner envisioned by
Congress.’” Robins, 967 F.2d at 1390 (quoting United States
v. Chan Yu-Chong, 920 F.2d 594, 597 (9th Cir. 1990)).
18                 UNITED STATES V. STEWART

    The district court understandably did not analyze the
usability of Stewart’s GHB mixture because Stewart did not
raise the issue of usability in the district court. We strongly
suspect, however, that the GHB mixture was unusable, which
would have a significant effect on Stewart’s non-career
offender guidelines range. At the concentration Stewart sold
the mixture (0.00055 grams of GHB per milliliter of water),
one would have to consume about a half-gallon of liquid to
obtain a single “usable” dose of GHB, even assuming that
GHB this dilute would have any effect at all. If the GHB was
in fact unusable, the relevant benchmark for purposes of
sentencing would be an approximation of the amount of
usable mixture he distributed, that is, a useable solution
containing six grams of dissolved GHB. See Stewart,
361 F.3d at 378–79 (holding that a court must determine “the
amount of drug that the defendant could have extracted from
something that is unusable at the time of arrest”); Acosta,
963 F.2d at 555 (holding that a sentence should “be based on
the amount of the usable mixture – not the pure cocaine, but
the cocaine mixed with the ingestible cutting agents” (citing
United States v. Rolande-Gabriel, 938 F.2d 1231, 1237 (11th
Cir. 1991)).6,7

  6
    Here, for example, the drug quantity might be one liter or less, based
on the total volume of liquid in which six grams of pure GHB could be
diluted to produce a usable product.
   7
     The district court also reasoned that no variance was warranted
because, given the price Stewart charged for the GHB, he “intended his
buyers to believe that his product was of a sufficient purity to produce an
intended effect.” In these circumstances, the court concluded that Stewart
would be held accountable for the entire volume of the GHB mixture
under the non-career offender guidelines, whether or not the GHB was
usable. We again disagree. A defendant who agrees to sell a specified
quantity of a controlled substance is typically held accountable for the
agreed-upon quantity, “unless the sale is completed and the amount
                  UNITED STATES V. STEWART                           19

    Accordingly, Stewart’s non-career offender guidelines
range likely would have been far lower than the 46 to 57
months calculated by the district court, based on a much
smaller volume of usable GHB mixture. Moreover, whether
or not the district court miscalculated Stewart’s non-career
offender range, the purity or diluteness of a drug mixture can
be a relevant factor for determining whether a sentence is
“sufficient, but not greater than necessary” under § 3553(a).
The district court was incorrect to presume otherwise.

    B. Career Offender Guidelines

    Stewart also argues that his sentence is unreasonable
because the career offender guidelines over-represent the
seriousness of his criminal history and risk of recidivism, and
that the these provisions are inherently flawed as applied in
any case. He contends he was a low-level dealer selling
drugs to support his own addiction, and his two past drug
distribution crimes were only minor offenses. The district
court rejected his arguments, although it nonetheless varied
downward, and its reasoning is supported by the record.

    The court properly recognized that it could give less
deference to or depart from the career offender provisions
based on either Stewart’s individual circumstances or a
general policy disagreement with the provisions, see United
States v. Henderson, 649 F.3d 955, 964 (9th Cir. 2011);


delivered more accurately reflects the scale of the offense.” U.S.S.G.
§ 2D1.1 cmt. n.5 (emphasis added). Here, Stewart may have agreed to sell
gallons of usable GHB to the agent, but he delivered a large amount of an
apparently unusable product. Properly taking usability into account, the
amount of usable drug product Stewart delivered would “more accurately
reflect[] the scale of [his] offense.” Id.
20              UNITED STATES V. STEWART

United States v. Mitchell, 624 F.3d 1023, 1027–30 (9th Cir.
2010), but it found that application of these provisions would
not “result[] in a sentence greater than necessary” in this case.
In the court’s view, Stewart had “demonstrated a willingness
to engage in criminal conduct,” and it accurately observed
that “both of his prior convictions as with the present
conviction concern not only a series of escalating transactions
but a demonstrated willingness . . . to engage in sales of
greater amounts of the controlled substances.” The court’s
determination that “[d]espite two prior convictions, each with
increasingly severe sentences, [Stewart] has demonstrated
that he will not be deterred from further criminal action,” is
supported by the record. The district court therefore
reasonably concluded that the substantial increase in sentence
called for by the career offender provision was not
“unwarranted or greater than necessary in the circumstances
of this case,” because it would serve “to protect the public
from further criminal action by [Stewart].”

    Stewart has a different view of the seriousness of his past
offenses than the district court, but the district court’s
interpretation of Stewart’s criminal history and potential for
recidivism was not “illogical, implausible, or without support
in inferences that may be drawn from the facts in the record.”
United States v. Treadwell, 593 F.3d 990, 999 (9th Cir. 2010)
(quoting United States v. Hinkson, 585 F.3d 1247, 1263 (9th
Cir.2009) (en banc)) (internal quotation marks omitted). Its
findings also accord with the policy behind the career
offender guidelines, which focuses on enhancing the penalties
of recidivist distributors of controlled substances. See Rivera,
996 F.2d at 996; United States v. Sanchez, 517 F.3d 651, 668
(2d Cir. 2008) (“[Section] 994(h) reflects Congress’s policy
judgment that . . . drug trafficking felonies generally warrant
more severe sentences when committed by recidivists than
                UNITED STATES V. STEWART                     21

when committed by first- or second-time offenders.”). The
district court could have disagreed with the policy behind the
career offender guidelines and sentenced Stewart accordingly,
but it was not required to do so. See Mitchell, 624 F.3d at
1030.

   C. Totality of the Circumstances

    Considering the totality of the circumstances, the district
court did not abuse its discretion in sentencing Stewart to 120
months’ imprisonment. As explained, the district court relied
on a mistaken assumption when it declined to vary from the
career offender guidelines based on the purity of the GHB
mixture. But we are not persuaded the mistake affected the
court’s choice of sentence or the overall reasonableness of the
sentence it chose. The purity and usability of a drug mixture
are but a few of the many relevant factors that weigh into
imposition of an individualized sentence under § 3553(a). Cf.
Treadwell, 593 F.3d at 1012. Fundamentally, the district
court based Stewart’s sentence on its agreement with the
sentencing range provided by the career offender guidelines,
a range that does not depend on the quantity of GHB – usable
or otherwise – involved in an offense. The court reasonably
explained why no variance from these provisions would be
justified based on Stewart’s criminal history. It then varied
downward by 31 months from the low end of Stewart’s career
offender guidelines range with the hope that Stewart would
rehabilitate himself while incarcerated. We afford “due
deference to the District Court’s reasoned and reasonable
decision that the § 3553(a) factors, on the whole, justified the
sentence.” Gall, 552 U.S. at 59–60. Although we may “think
a different sentence is appropriate,” Carty, 520 F.3d at 993,
the district court did not make “a clear error of judgment in
the conclusion it reached upon weighing the relevant factors,”
22              UNITED STATES V. STEWART

Ressam, 679 F.3d at 1087 (quoting Amezcua-Vasquez,
567 F.3d at 1055) (internal quotation marks omitted).

                             IV

     For the foregoing reasons, we affirm Stewart’s sentence.

     AFFIRMED.
