                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                  No. 05-10365
                Plaintiff-Appellee,
               v.                            D.C. No.
                                          CR-04-00035-LRH
ROBERT DEAN ELLSWORTH,
                                             OPINION
             Defendant-Appellant.
                                      
       Appeal from the United States District Court
                for the District of Nevada
        Larry R. Hicks, District Judge, Presiding

                   Argued and Submitted
         April 6, 2006—San Francisco, California

                   Filed August 9, 2006

   Before: Alfred T. Goodwin, Betty Binns Fletcher and
           Raymond C. Fisher, Circuit Judges.

                 Opinion by Judge Fisher




                           9201
9204              UNITED STATES v. ELLSWORTH
                          COUNSEL

Cynthia S. Hahn, Assistant Federal Public Defender, Reno,
Nevada, for the defendant-appellant.

Robert Don Gifford, Assistant United States Attorney, Reno,
Nevada, for the plaintiff-appellee.


                          OPINION

FISHER, Circuit Judge:

   Robert Dean Ellsworth was convicted of robbery and first
degree murder and sentenced to life imprisonment with the
possibility of parole by a Nevada state court in 1988. He was
paroled after serving 16 years. One year and one day after his
release, he was arrested while in the possession of a loaded
nine millimeter semiautomatic handgun. A subsequent search
of his car and room uncovered additional ammunition and a
shoulder holster for the weapon. Ellsworth pled guilty to
being a felon in possession of a firearm in violation of 18
U.S.C. § 922(g)(1).

    At the sentencing hearing and over Ellsworth’s objection,
the district court applied a two-level offense enhancement in
accordance with the advisory Sentencing Guidelines because
the firearm he possessed was stolen. See U.S.S.G.
§ 2K2.1(b)(4) (2003). The government admitted that it could
not prove Ellsworth knew that the gun was stolen, but accord-
ing to the terms of this particular Guideline, knowledge is not
necessary for this offense enhancement to apply. See id.; see
also id. cmt. n.19 (“The enhancement under subsection (b)(4)
for a stolen firearm . . . applies whether or not the defendant
knew or had reason to believe that the firearm was stolen
. . . .”). The district court also increased Ellsworth’s criminal
history score by two categories because the court found that
                  UNITED STATES v. ELLSWORTH               9205
the Guidelines’ criminal history calculation significantly
underrepresented the seriousness of Ellsworth’s prior
offenses. Accordingly, the district court imposed a 78-month
sentence — roughly double the length the probation office
had recommended in its presentence report but well within the
10-year statutory maximum for a § 922(g)(1) offense. See 18
U.S.C. § 924(a)(2).

   Ellsworth appeals the two-level offense enhancement for
the stolen gun, arguing that the absence of a scienter require-
ment for stolen weapons is unconstitutionally irrational given
that knowledge is required for possession of stolen explo-
sives. He also challenges the two-category increase in his
criminal history score and the overall reasonableness of his
sentence. We have jurisdiction under 28 U.S.C. § 1291, and
we affirm.

                  I.   Standard of Review

   We review the constitutionality of a Sentencing Guideline
de novo. See United States v. Marcial-Santiago, 447 F.3d
715, 717 (9th Cir. 2006). Further, we “review[ ] the district
court’s interpretation of the Sentencing Guidelines de novo,
the district court’s application of the Sentencing Guidelines to
the facts of this case for abuse of discretion, and the district
court’s factual findings for clear error.” United States v. Kim-
brew, 406 F.3d 1149, 1151 (9th Cir. 2005). “Even though the
Guidelines are no longer mandatory after . . . United States v.
Booker, the district court should still consult them for advice
as to the appropriate sentence, and we therefore address the
merits of” challenges to the district court’s interpretation and
application of the Guidelines. Id. at 1152 (internal citations
omitted). “In the absence of Guidelines application error, . . .
we will then proceed to address challenges to the reasonable-
ness of the sentence.” United States v. Cantrell, 433 F.3d
1269, 1280 (9th Cir. 2006).
9206             UNITED STATES v. ELLSWORTH
       II.   Knowledge that the Firearm Was Stolen

   [1] Ellsworth contends that the Sentencing Guidelines vio-
late his Fifth Amendment right to equal protection by treating
supposedly similarly situated felons differently without a
rational basis. Specifically, the Guidelines impose a two-level
sentencing enhancement for possession of a stolen firearm
regardless of knowledge that the firearm was stolen, see
U.S.S.G. § 2K2.1(b)(4) (2003), whereas the two-level
enhancement for possession of stolen explosives applies only
when “the defendant knew or had reason to believe” the
explosives were stolen, see id. § 2K1.3(b)(2). Ellsworth
argues that the relatively harsher treatment of felons in pos-
session of stolen firearms is irrational because “stolen explo-
sives . . . are far more dangerous” than stolen firearms. We
disagree, and hold that the Guidelines’ different scienter
requirements for stolen firearms and stolen explosives are
rationally related to a legitimate government interest and thus
there is no equal protection violation.

   Both before and after United States v. Booker, 543 U.S. 220
(2005), we have applied the rational basis standard of review
to equal protection challenges to the Sentencing Guidelines
based on a comparison of allegedly disparate sentences. See
Marcial-Santiago, 447 F.3d at 719 (applying rational basis
review to equal protection challenge comparing length of sen-
tences in jurisdictions that had adopted “fast-track” sentenc-
ing programs to those in jurisdictions that had not); United
States v. Harding, 971 F.2d 410, 412 (9th Cir. 1992) (holding
that differences in sentences between crack and powder
cocaine offenses “implicate[ ] neither a suspect class nor a
fundamental right” and therefore rational basis scrutiny is
appropriate); United States v. Fine, 975 F.2d 596, 604 (9th
Cir. 1992) (applying rational basis review to distinction
between which offenses are groupable under U.S.S.G.
§ 3D1.2(d) and which are not, and recognizing that “[t]he Due
Process Clause of the Fifth Amendment precludes the imposi-
tion of punishment based on arbitrary distinctions, and, in the
                    UNITED STATES v. ELLSWORTH                      9207
sentencing context, ‘essentially duplicates’ an argument based
on equal protection” (quoting Chapman v. United States, 500
U.S. 453, 465 (1991)).

   [2] Under rational basis review, the distinction for sentenc-
ing purposes between felons in possession of stolen firearms
and those in possession of stolen explosives “must be upheld
against equal protection challenge if there is any reasonably
conceivable state of facts that could provide a rational basis
for the classification.” FCC v. Beach Commc’ns, 508 U.S.
307, 313 (1993) (emphasis added). It is reasonably conceiv-
able that although explosives are in theory more deadly than
firearms when compared on an individualized basis, stolen
firearms are more readily obtainable by felons and therefore
more deadly than stolen explosives in the aggregate. “Or so
the legislature may think.” Williamson v. Lee Optical of
Okla., Inc., 348 U.S. 483, 489 (1955); see also id. at 487-88
(upholding an Oklahoma law under equal protection rational
basis review by positing numerous hypothetical justifications
for the law without considering whether or not the legislature
actually considered such justifications).

   [3] Two other circuits have expressly noted the “great dan-
gers” posed by ex-felons in possession of stolen firearms and
reasoned that the absence of a scienter requirement in
§ 2K2.1(b)(4) “reflects this heightened danger.” United States
v. Schnell, 982 F.2d 216, 221 (7th Cir. 1992) (citing United
States v. Mobley, 956 F.2d 450, 454 (3d Cir. 1992)). Relying
on Mobley and Schnell, we have recognized that the two-level
enhancement for stolen firearms in § 2K2.1(b)(4) “was pro-
mulgated on the premise that stolen firearms are used dispro-
portionately in the commission of crimes” and that “an ex-
felon who obtains a stolen firearm is more culpable than one
who legally obtains a firearm.” United States v. Goodell, 990
F.2d 497, 499 (9th Cir. 1993) (relying on rational basis review
to uphold § 2K2.1(b)(4) against a due process challenge).1
  1
   The stolen firearm sentencing enhancement analyzed in Goodell had
been codified as U.S.S.G. § 2K2.1(b)(2) (1990) (“If the firearm was stolen
9208                UNITED STATES v. ELLSWORTH
   Further, a “legislature must be allowed leeway to approach
a perceived problem incrementally” without violating the
Equal Protection Clause. Beach Communications, 508 U.S. at
316 (relying on Williamson, 348 U.S. at 489). In the late
1980s, the Sentencing Commission decided to remove the
scienter requirement from § 2K2.1(b)(4). “[B]oth the structure
and the history of the guidelines clearly show that the Sen-
tencing Commission intended to omit the element of mens rea
in § 2K2.1(b)(4).” Schnell, 982 F.2d at 220 (emphasis added).
The Commission took no such steps to revise § 2K1.3(b)(2),
the analogous Guideline enhancement applicable to stolen
explosives. The Commission’s revision of § 2K2.1(b)(4) and
inaction with respect to § 2K1.3(b)(2) may reflect a rational,
but incremental, reform of a number of Guidelines concerned
with dangerous stolen items in the possession of felons.

   [4] Lastly, Ellsworth argues that the Sentencing Commis-
sion has failed to “bow to the specific directives of Congress”
with respect to § 2K2.1(b)(4). United States v. LaBonte, 520
U.S. 751, 757 (1997). More specifically, he contends that the
Commission’s decision to remove scienter from § 2K2.1(b)(4)
“is at odds with [Congress’] plain language,” id. at 757, as
expressed in 18 U.S.C. § 922(j), a statute that criminalizes the
possession of a stolen firearm by “any person” who “know[s]
or ha[s] reasonable cause to believe that the firearm or ammu-
nition was stolen.” But unlike the conflict addressed in
LaBonte between the Sentencing Commission’s commentary
and Congress’ intent, here there is no conflict between the
lack of a scienter requirement in the § 2K2.1(b)(4) sentencing
enhancement and the scienter requirement in 18 U.S.C.
§ 922(j).

or had an altered or obliterated serial number, increase by 2 levels.”) —
the enhancement was moved to § 2K2.1(b)(4) in 1991. See Goodell, 990
F.2d at 498 n.1. Save for the substitution “any firearm” for “the firearm”
and the addition of a comma after “was stolen,” § 2K2.1(b)(2) (1990) is
identical to § 2K2.1(b)(4) (2003). The slight differences between them are
not relevant in this case.
                  UNITED STATES v. ELLSWORTH                9209
   [5] Although superficially similar to the statutory offense in
§ 922(j), § 2K2.1(b)(4) is only a Guideline enhancement and
not an independent basis for criminal liability. As applied to
Ellsworth, the § 2K2.1(b)(4) enhancement increases the cul-
pability of felons in possession of stolen firearms, a much
smaller and distinct category of persons than the broad “any
person” category covered by § 922(j). Because “Congress has
called upon the Commission to exercise its judgment about
which types of crimes and which types of criminals are to be
considered similar for the purposes of sentencing,” Mistretta
v. United States, 488 U.S. 361, 377-78 (1989), and because
Congress expressly intended that “an ex-felon may not legiti-
mately possess any firearm,” Goodell, 990 F.2d at 499
(emphasis added), we cannot infer congressional intent
regarding the mens rea requirement for a felon who possesses
a stolen firearm from the mens rea requirement for the generic
category of “any person” who possesses a stolen firearm.

   [6] Similarly, the absence of a requirement that a felon who
possesses a stolen firearm know that the firearm is stolen is
distinguishable from the situation in Staples v. United States,
511 U.S. 600 (1994). The defendant in Staples did not know
that his gun had the requisite characteristics to classify it as
a machine gun. See id. at 609. However, as discussed above,
§ 2K2.1(b)(4) was applied to enhance Ellsworth’s sentence
only after he was convicted of an offense under 18 U.S.C.
§ 922(g)(1), which prohibits felons from possessing any fire-
arms, not just stolen firearms. Ellsworth never suggests that
he did not know that the nine millimeter semiautomatic hand-
gun he possessed was a firearm.

   [7] The district court did not err in applying the two-level
stolen-weapon enhancement.
9210                 UNITED STATES v. ELLSWORTH
      III.   Underrepresented Criminal History Score and
                           Reasonableness

   Ellsworth next contends that the district court’s two-
category increase in his criminal history score violated his
Sixth Amendment jury trial right, see Taylor v. United States,
495 U.S. 575 (1990), and his Fifth Amendment right to due
process. Both arguments lack merit. Moreover, Ellsworth’s
sentence — which the district court based in part on “stale”
prior offenses that would not ordinarily be counted towards
his criminal history score because they were committed too
long ago to be considered under U.S.S.G. § 4A1.2(e) (2003)
— was reasonable.2

   On appeal, Ellsworth argues for the first time that “the dis-
trict court erred in increasing [his] criminal history category
from III to V because no documentation was provided to
prove up the priors pursuant to Taylor . . . .” Accordingly, we
must determine whether that increase in his criminal history
score constituted plain error. See FED. R. CRIM. P. 52(b) (“A
plain error that affects substantial rights may be considered
even though it was not brought to the court’s attention.”)
Because Ellsworth fails the first requirement of plain error
review — “that there indeed be an ‘error,’ ” United States v.
  2
   U.S.S.G. § 4A1.2(e) (2003) reads in relevant part as follows:
      (e) Applicable Time Period
      (1) Any prior sentence of imprisonment exceeding one year and
      one month that was imposed within fifteen years of the defen-
      dant’s commencement of the instant offense is counted. Also
      count any prior sentence of imprisonment exceeding one year and
      one month, whenever imposed, that resulted in the defendant
      being incarcerated during any part of such fifteen-year period.
      (2) Any other prior sentence that was imposed within ten years
      of the defendant’s commencement of the instant offense is
      counted.
      (3) Any prior sentence not within the time periods specified
      above is not counted . . . .
                  UNITED STATES v. ELLSWORTH               9211
Olano, 507 U.S. 725, 732 (1993) — his Taylor argument is
without merit.

   Ellsworth misapprehends the instances where the Taylor
categorical and modified categorical approaches are applica-
ble. We rely upon Taylor in the context of sentencing to deter-
mine whether a prior conviction fits within the scope of a
generically defined crime, such as an “aggravated felony” or
a “crime of violence.” See, e.g., United States v. Rivera-
Sanchez, 247 F.3d 905, 907 (9th Cir. 2001) (en banc) (sen-
tencing); cf. Morales-Alegria v. Gonzales, 449 F.3d 1051,
1057 (9th Cir. 2006) (removal).

   [8] However, for the most part a criminal history calcula-
tion is not predicated on the commission of an underlying
generically defined crime. Instead, the criminal history score
looks to the defendant’s prior sentence of imprisonment, the
length of that sentence, the defendant’s parole status and the
length of time between his commission of the instant offense
and his release from a previous term of imprisonment. See
U.S.S.G. § 4A1.1 (2003). The Taylor problem does not arise
when dealing with such criminal history facts because they
are independent of the nature of the underlying offense. Only
subsection (f) of § 4A1.1 could potentially raise a cognizable
Taylor issue, because it refers to an underlying prior convic-
tion for “a crime of violence.” However, the district court, in
evaluating whether Ellsworth’s criminal history score was
underrepresented due to exclusion of stale offenses, did not
rely on § 4A1.1(f). Instead, the court looked to the other sub-
sections of § 4A1.1 to determine what Ellsworth’s criminal
history score would have been had his previous sentences not
been too old to be considered under § 4A1.2(e). See supra
note 2. Therefore, the district court did not commit a Taylor
error.

  Next, Ellsworth argues that the district court violated his
Fifth Amendment due process right when it relied upon what
he calls the “unsubstantiated priors” in the presentence report.
9212              UNITED STATES v. ELLSWORTH
However, Ellsworth conceded at the sentencing hearing that
the presentence report listing his prior offenses was factually
accurate. Accordingly, he has waived any challenge to the
accuracy of the presentence report. See Olano, 507 U.S. at
733 (“[W]aiver is the intentional relinquishment or abandon-
ment of a known right . . . . [W]aiver . . . extinguish[es] an
‘error’ under Rule 52(b).” (internal citations and quotation
marks omitted)).

   [9] We understand Ellsworth’s final criminal history argu-
ment to be a “challenge[ ] to the reasonableness of the overall
sentence in light of all the 18 U.S.C. § 3553(a) factors.” Can-
trell, 433 F.3d at 1280. Ellsworth contends that the district
court “unreasonably [gave] undue weight to the murder for
which Mr. Ellsworth was already being punished in both the
State and federal systems” and that, “except for his conviction
in Nevada for first degree murder, . . . his criminal history
consisted of little more than misdemeanors with one prior fel-
ony burglary . . . .” We conclude that the district court did not
give undue weight to Ellsworth’s murder conviction and that
it was reasonable for the district court to increase his criminal
history score from a category III to a category V.

   In United States v. Menyweather, 447 F.3d 625, 634 (9th
Cir. 2006), we recognized that post-Booker district courts may
now engage in a “broader appraisal . . . of the defendant’s his-
tory and characteristics for reasons extending beyond the
Guidelines” when deciding upon an appropriate sentence.
(Internal quotation marks and citations omitted.) The district
court properly understood and articulated the role that advi-
sory Guidelines play in sentencing: “[U]nder Booker and Fan-
fan, [this court] has a certain amount of discretion to go
beyond the guidelines or below the guidelines, but my first
obligation is to consider the guidelines.” Accord Kimbrew,
406 F.3d at 1152 (“Even though the Guidelines are no longer
mandatory after . . . United States v. Booker, the district court
should still consult them for advice as to the appropriate sen-
tence . . . .”).
                      UNITED STATES v. ELLSWORTH                           9213
   The district court discussed at length “the nature and cir-
cumstances of the offense” and Ellsworth’s “history and char-
acteristics.” 18 U.S.C. § 3553(a)(1).3 It noted that Ellsworth,
“this convicted murderer[, was] seated in the casino with a
fully-loaded semiautomatic nine millimeter weapon which
[had] recently been stolen from a law enforcement officer.”
“[T]he presence of the holster [purchased by Ellsworth] and
the loading of the weapon suggests that those were intentional
acts by Mr. Ellsworth that were designed and intended to
allow him to carry a loaded weapon . . . on more than one
occasion.”

  Explaining its decision to consider what Ellsworth’s crimi-
nal history score would have been were his older convictions
added in, the court reasoned that

      [i]t is only because he was in the Nevada State
      Prison on a life sentence that these prior convictions
      became stale under the sentencing guidelines and
      time dated. . . . [N]ormally a defendant who is con-
      victed of first degree murder and sentenced to a life
      sentence will . . . seldom, if ever, have that convic-
      tion come back to be calculated again in a subse-
      quent offense.

The court concluded that Ellsworth’s criminal history “closely
resembles a V criminal history category as that is applied gen-
erally to criminal history V defendants.” In reaching that con-
  3
    The sentencing court does not need to discuss explicitly all of the
§ 3553(a) factors. See United States v. Mix, 450 F.3d 375, 381 (9th Cir.
2006) (“Judges need not rehearse on the record all of the considerations
that 18 U.S.C. § 3553(a) lists; it is enough to calculate the range accurately
and explain why (if the sentence lies outside it) this defendant deserves
more or less.” (internal citation and quotation marks omitted)). However,
“after Booker, the district court still is required to articulate the reasons for
the extent of the departure in sufficiently specific language to allow appel-
late review.” Menyweather, 447 F.3d at 635 (internal quotations marks
omitted). The district court satisfied that requirement here.
9214              UNITED STATES v. ELLSWORTH
clusion, the district court did not give undue weight to
Ellsworth’s murder and robbery convictions, as Ellsworth
suggests. The court was at least as concerned (if not more)
about the nature of the instant offense and the length and seri-
ousness of Ellsworth’s criminal history as it was about the
heinousness of the murder he had committed.

   We also disagree with Ellsworth’s characterization of his
criminal history before his murder and robbery convictions as
not being particularly serious, or at least no more serious than
that of the defendant in United States v. Bad Marriage, 392
F.3d 1103, 1115 (9th Cir. 2004). Ellsworth is plainly a more
serious offender than was Bad Marriage — most obviously
because of Ellsworth’s murder and robbery convictions. Fur-
ther, his other prior convictions (and terms of imprisonment)
for burglary, battery, possession and sale of a switchblade and
grand larceny were also serious, especially when considered
together. We conclude that the district court’s characterization
of Ellsworth’s criminal history was reasonable: “[I]t’s cer-
tainly an aggravated criminal history[,] and it reflects both
violent and intentional criminal conduct over an extended
period of time which is egregious to the point that it certainly
supports the upward placement in the V.” Therefore the two-
category increase in Ellsworth’s applicable criminal history
score was reasonable as well.

                      IV.   Conclusion

   The different scienter requirements of the sentencing
enhancements for felons in possession of stolen firearms and
stolen explosives are rationally related to a legitimate govern-
ment interest and do not violate the Equal Protection Clause.
There was no need for the district court to conduct an analysis
under Taylor v. United States, 495 U.S. 575 (1990), when it
relied on Ellsworth’s “stale” prior offenses to increase his
criminal history score. Ellsworth’s admission during sentenc-
ing that the presentence report was accurate precludes his
Fifth Amendment due process claim. The sentence imposed
                  UNITED STATES v. ELLSWORTH                9215
by the district court, based in part on prior offenses that would
not ordinarily be counted towards Ellsworth’s criminal history
score under U.S.S.G. § 4A1.2(e) (2003), was reasonable.

  AFFIRMED.
