 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued December 14, 2017              Decided July 17, 2018

                        No. 16-3126

               UNITED STATES OF AMERICA,
                       APPELLEE

                             v.

                    MICHAEL MATTEA,
                       APPELLANT


        Appeal from the United States District Court
                for the District of Columbia
                   (No. 1:16-cr-00093-1)


     Mary E. Davis, appointed by the court, argued the cause
for appellant. With her on the briefs was Thomas Abbenante,
appointed by the court.

    David P. Saybolt, Assistant U.S. Attorney, argued the
cause for appellee. With him on the brief were Channing D.
Phillips, U.S. Attorney, and Elizabeth Trosman, Elizabeth H.
Danello, and Lindsay Suttenberg, Assistant U.S. Attorneys.

    Before: GRIFFITH, MILLETT, and PILLARD, Circuit Judges.

    Opinion for the Court filed by Circuit Judge GRIFFITH.
                               2

     GRIFFITH, Circuit Judge: Michael Mattea pleaded guilty to
the distribution of child pornography and agreed to an
estimated sentencing range of 151 to 188 months in prison
under the U.S. Sentencing Guidelines (“Guidelines”). The
district court sentenced Mattea to 151 months’ incarceration.
Mattea appeals, arguing that the district court abused its
discretion by miscalculating the Guidelines range through
application of an inappropriate enhancement and by refusing to
impose a sentence below the Guidelines range. We reject
Mattea’s arguments and affirm the district court’s sentence.

                               I

     In February 2016, Mattea emailed someone he believed
was the parent of a ten-year-old girl, but who turned out to be
an undercover officer from the Federal Bureau of Investigation.
Mattea told the officer he had a sexual interest in children and
wanted to meet and sexually abuse the officer’s purported
daughter. Then, in March, Mattea sent the officer several
sexually explicit images of a prepubescent girl who appeared
to be between eleven and twelve years old.

     Officers shortly thereafter arrested Mattea at his home in
West Virginia. Investigators seized Mattea’s cell phone,
computers, and other electronic devices. All told, law-
enforcement officials found 187 videos and 116 images
depicting child pornography, including videos depicting sexual
acts with infants and toddlers.

     In October 2016, Mattea pleaded guilty to distribution of
child pornography in violation of 18 U.S.C. § 2252(a)(2). As
part of his plea agreement, Mattea acknowledged that, under
the Guidelines, his violation of § 2252(a)(2) set his “base
offense level” at twenty-two (the highest level being forty-
three). Mattea also agreed to the application of several
                               3

enhancements that would increase his offense level and his
estimated range of punishment. Specifically, Mattea received
enhancements because his child-pornography offense
concerned material involving a prepubescent minor or minor
under twelve, U.S.S.G. § 2G2.2(b)(2); distribution of
contraband, id. § 2G2.2(b)(3)(F); portrayal of sadistic or
masochistic conduct, id. § 2G2.2(b)(4); use of a computer, id.
§ 2G2.2(b)(6); and 600 or more images of child pornography,
id. § 2G2.2(b)(7)(D). In his plea agreement, Mattea expressly
reserved the right to challenge the application of the computer-
use enhancement at his sentencing hearing. These
enhancements collectively added fifteen levels to Mattea’s
base offense level.

    Mattea’s range was also adjusted three levels downward
based on Mattea’s demonstrated acceptance of responsibility
and his cooperation with authorities. After applying each of
these enhancements and downward adjustments, Mattea’s total
offense level yielded an estimated Guidelines range of 151 to
188 months’ incarceration. Mattea agreed that any sentence
within that range would be reasonable.

     The district court ultimately sentenced Mattea to 151
months’ imprisonment, followed by 240 months of supervised
release. Mattea now appeals his sentence.

                               II

    The district court had jurisdiction to impose Mattea’s
sentence pursuant to 18 U.S.C. § 3231. We have jurisdiction
over Mattea’s appeal pursuant to 18 U.S.C. § 3742(a) and 28
U.S.C. § 1291.

    The government argues that Mattea waived the right to
appeal his sentence in his plea agreement. Mattea responds that
                               4

his appeal waiver should not be enforced because the district
court mischaracterized the waiver in a colloquy with Mattea
during his plea hearing. See United States v. Godoy, 706 F.3d
493, 494-96 (D.C. Cir. 2013). Because the validity of an appeal
waiver does not go to our jurisdiction, we need not address the
question if we reject Mattea’s challenge on the merits, which,
as explained below, we do. See United States v. Shemirani, 802
F.3d 1, 3 (D.C. Cir. 2015).

                               III

     Appellate review of sentencing decisions “is limited to
determining whether they are ‘reasonable.’” Gall v. United
States, 552 U.S. 38, 46 (2007). We follow a two-step procedure
for assessing a sentence’s reasonableness.

     First, we “ensure that the district court committed no
significant procedural error,” such as “improperly calculating[]
the Guidelines range,” “failing to consider the [appropriate]
factors,” or “failing to adequately explain the chosen sentence.”
Id. at 51.

     Second, if the sentencing court’s decision is procedurally
sound, we consider the “substantive reasonableness” of the
sentence. Id. Our review for substantive reasonableness is
“quite deferential,” United States v. Knight, 824 F.3d 1105,
1111 (D.C. Cir. 2016), and it will be an “unusual case when
[we] can plausibly say that a sentence is so unreasonably high
or low” as to warrant reversal, United States v. Gardellini, 545
F.3d 1089, 1093 (D.C. Cir. 2008). Moreover, a “sentence
within a properly calculated Guidelines range is entitled to a
rebuttable presumption of reasonableness.” United States v.
Law, 806 F.3d 1103, 1106 (D.C. Cir. 2015) (quoting United
States v. Dorcely, 454 F.3d 366, 376 (D.C. Cir. 2006)).
                              5

     We review claims of procedural error and substantive
unreasonableness for abuse of discretion. Gall, 552 U.S. at 51;
see also United States v. Wilson, 605 F.3d 985, 1034 (D.C. Cir.
2010).

                              IV

                              A

     Mattea argues that in its calculation of his Guidelines
range, the district court erred when it applied the two-level
increase for a child-pornography offense involving the use of a
computer. See U.S.S.G. § 2G2.2(b)(6). Mattea does not dispute
that he used a computer to possess and distribute pornographic
images. Instead, Mattea relies on a February 2013 report issued
by the U.S. Sentencing Commission, the independent agency
tasked with developing and updating the Guidelines, to point
out that “given today’s technology, every offense of possessing
or distributing child pornography involves a computer.” Mattea
Br. 19; see also U.S. Sent’g Comm’n, Report to the Congress:
Federal Child Pornography Offenses 323-24 (2012)
(explaining that the computer-use enhancement “applies in
virtually every case”). Due to the ubiquity of computers,
Mattea contends that the computer-use enhancement, first
established in 1996, now “fail[s] to differentiate among
offenders in terms of their culpability.” U.S. Sent’g Comm’n,
supra, at iii.

    Since the Supreme Court’s decision in United States v.
Booker, 543 U.S. 220 (2005), the Guidelines serve only an
advisory function. Id. at 245. Nevertheless, even in a post-
Booker world in which the Guidelines are not binding, the
sentencing court “must calculate and consider the applicable
Guidelines range” as its starting point. Dorcely, 454 F.3d at
                               6

375. And Booker did not change “how the Guidelines range is
to be calculated.” Id. at 375 n.6.

     The district court adequately considered Mattea’s
argument and acted within its sound discretion to reject it. The
computer-use enhancement is written in mandatory language:
“If the offense involved the use of a computer . . . for the
possession, transmission, receipt, or distribution of the
material, . . . increase by 2 levels.” U.S.S.G. § 2G2.2(b)(6). As
the district court aptly noted, “The law as it currently exists
makes that enhancement an enhancement for that [child-
pornography] offense.” Responding to defense counsel’s
concerns, the district court recognized that the enhancement
could act as a “double hit” given its application in almost every
present-day child-pornography offense under § 2252(a)(2).
Even so, the district court also explained that its role in
calculating the Guidelines range was not that of a “policy
maker.” Instead, the district court was limited to “apply[ing]
the Guidelines as currently constructed and the enhancements
as currently styled.” According to the district court, this
enhancement’s near-universal application in child-
pornography cases presented policy issues that Congress itself
would have to address.

     Even so, the district court suggested that though Mattea
could not use his policy-based argument in a challenge to how
his sentencing range was calculated, “certainly” he could use
the argument “to . . . seek a variance downward from an
existing Guidelines Range[].” Mattea’s counsel acknowledged
that he could pursue the variance argument and did so later in
the hearing. The record thus confirms that the district court
“considered” Mattea’s argument against applying the
enhancement and offered a “reasoned basis” for rejecting it.
United States v. Lafayette, 585 F.3d 435, 440 (D.C. Cir. 2009)
(quoting Rita v. United States, 551 U.S. 338, 356 (2007)). The
                                7

district court recognized both the limitations that the
Guidelines placed on the court when calculating Mattea’s range
and the discretion it retained to vary from that correctly
calculated range.

     Whatever the merits of Mattea’s policy dispute with the
Guidelines’ computer-use enhancement, the district court did
not abuse its discretion by applying it here. We recently
addressed a similar situation in United States v. Fry, 851 F.3d
1329 (D.C. Cir. 2017), involving a defendant likewise
sentenced for a child-pornography offense. The defendant in
Fry argued that the sentencing court should have granted him
a downward variance from the Guidelines range based solely
on a policy disagreement with the Guidelines. In particular, the
defendant maintained that a downward variance was required
because many of his sentence’s enhancements—including use
of a computer—“applied in the vast majority of cases.” Id. at
1333. We rejected that argument because “a district court does
not necessarily abuse its discretion by agreeing with (and
applying) [the child-pornography] Guidelines.” Id. at 1334.

     Of course, Mattea’s case is not exactly like Fry. Mattea
challenges the calculation of his Guidelines range based on a
policy disagreement with the Guidelines. Fry only involved a
policy-based challenge to the district court’s decision not to
grant a downward variance; the defendant in Fry did not
challenge the district court’s decision to apply the relevant
enhancements when calculating his Guidelines range.
Despite this difference, the principle in Fry still controls here:
A district court generally does not abuse its discretion by
applying the Guidelines to the facts before it. If anything,
Mattea’s challenge is even less forceful than the one in Fry
because the district court’s discretion is greater when
considering downward variances than when calculating the
correct Guidelines range. Cf. United States v. Ballestas, 795
                               8

F.3d 138, 150 (D.C. Cir. 2015) (stating that sentencing courts
enjoy “substantial discretion . . . following calculation of the
guidelines range”); United States v. Haipe, 769 F.3d 1189,
1191 (D.C. Cir. 2014) (explaining that a “properly calculated
range frames the district court’s exercise of its discretion”).

     The district court did not abuse its discretion when
applying the computer-use enhancement. We therefore affirm
that aspect of Mattea’s sentence.

                               B

     Mattea also argues that the district court abused its
discretion by refusing Mattea’s request for a downward
variance from the calculated Guidelines range. We address in
turn the procedural and substantive elements of this challenge.

     Mattea claims the district court procedurally erred by
failing to adequately consider “the need to avoid unwarranted
sentence disparities among defendants with similar records
who have been found guilty of similar conduct.” 18 U.S.C.
§ 3553(a)(6). Mattea argued before the district court that a
substantial variance down to sixty months’ incarceration (the
statutory mandatory minimum) was justified after considering
the sentencing practices of other district court judges. For
instance, Mattea noted that in 2015 only 30.7% of those
convicted of federal child-pornography offenses nationwide
received a sentence within the Guidelines range, and 67.5% of
those convicted were sentenced below the range. Mattea even
presented a series of cases from our circuit in which judges
imposed sentences well below the calculated Guidelines range
for what Mattea considers to be similar conduct.

    In assessing Mattea’s procedural challenge, we must bear
in mind that
                                9


    the § 3553(a) factors that district courts must consider at
    sentencing are vague, open-ended, and conflicting;
    different district courts may have distinct sentencing
    philosophies and may emphasize and weigh the individual
    § 3553(a) factors differently; and every sentencing
    decision involves its own set of facts and circumstances
    regarding the offense and the offender.

Gardellini, 545 F.3d at 1093.

     Section 3553(a)(6) requires courts to consider avoiding
unwarranted disparities among defendants “with similar
records who have been found guilty of similar conduct.” It
“does not require the district court to avoid sentencing
disparities between []defendants who might not be similarly
situated.” United States v. Guillermo Balleza, 613 F.3d 432,
435 (5th Cir. 2010).

     Here, the district court adequately considered the need to
avoid unwarranted disparities and did not abuse its discretion
when concluding that Mattea was differently situated from
defendants for whom other district court judges granted
downward variances. The district court recognized that
avoiding unwarranted disparities is “one of the factors” it
needed to consider, and emphasized that Mattea’s crime did not
constitute “a typical case” of child pornography. The district
court sufficiently explained how the distinctly troubling
features of Mattea’s child-pornography offense warranted
Mattea’s sentence.

     As the government explained in its sentencing
memorandum, Mattea’s collection of child pornography was
“particularly disturbing” because he had images of toddler and
infant abuse. J.A. 133; see also J.A. 126 & n.4 (listing in
                               10

graphic detail some “particularly egregious” pieces of Mattea’s
child-pornography collection). The district court agreed,
concluding that Mattea’s collection of child pornography was
“extraordinary and outrageous and terrible and particularly
heinous,” necessitating sufficient punishment to deter others
“who might engage in conduct like this, who may engage in
collecting the type of pornography and the amount of
pornography that [Mattea] obtained.” Also, because Mattea
had sought to meet and sexually abuse a minor, the district
court explained that a within-Guidelines sentence would better
deter people from trying to arrange the type of meeting Mattea
sought.

     The district court did not procedurally err when invoking
the particular characteristics of Mattea’s offense to justify his
sentence. When an offense is uniquely serious, courts will
consider the need to impose “stiffer sentences” that “justif[y]
the risk of potential disparities.” United States v. Jones, 846
F.3d 366, 372 (D.C. Cir. 2017); see also United States v.
Accardi, 669 F.3d 340, 346 (D.C. Cir. 2012) (concluding that
a within-Guidelines sentence for a child-pornography offense
did not produce an unwarranted disparity when the images
distributed by the defendant “were much more aggressive and
troubling than the images distributed by other offenders” who
received lesser sentences). The district court considered the
aspects of Mattea’s crime that justified the disparity between
his within-Guidelines sentence and the below-Guidelines
sentences in this circuit. This was not procedural error.

     Mattea nevertheless contends that the district court’s
consideration of unwarranted disparities was defective because
the court’s analysis was infected by an irrelevant factor. When
the defense introduced the recent cases in which district court
judges in this circuit had granted downward variances for
child-pornography offenses, the district court discounted most
                                11

of those precedents as the products of “judges who were
appointed by President Obama in the last three or four years,
and who have very limited experience in sentencing in these
cases.”

     Mattea argues that these comments demonstrate that the
district court made its sentencing determination on the basis of
political beliefs. We disagree. To be sure, district courts should
avoid creating even an appearance of impropriety by making
comments that could be taken to be partisan. But as we read the
district court’s statements, they concerned recent judicial
appointees’ relative lack of sentencing experience, not politics.
To the extent that the district court’s perception of its additional
experience affected its judgment, this only reinforced the
court’s confidence in the need to impose a punishment “that’s
consistent with the seriousness of [Mattea’s] conduct” and
would “protect[] the public” through adequate deterrence.
These reasons for imposing a within-Guidelines sentence—
rooted in Mattea’s conduct and the need for public safety—are
not the products of politics. Moreover, throughout its
discussion of judicial experience, the district court was
centrally focused on the substantive differences between the
cases cited by the defense counsel and Mattea’s present
offense. The challenged statements do not detract from the
district court’s reasoned consideration of Mattea’s arguments
for a downward variance.

    Finally, Mattea argues that even if the district court
adequately considered the unwarranted-disparities factor, its
sentence of 151 months’ incarceration was nonetheless
substantively unreasonable. This is an unpersuasive challenge,
especially given that Mattea himself conceded in his plea
agreement that any within-Guidelines sentence would be
“reasonable.”
                               12

     Because Mattea’s sentence falls within the Guidelines
range, we presume it is reasonable. See Law, 806 F.3d at 1106.
Taking into account “the totality of the circumstances,” Gall,
552 U.S. at 51, we conclude that Mattea has not rebutted that
presumption. We “cannot say that the [district] court acted
unreasonably” when concluding that the egregious character of
Mattea’s offense necessitated a more severe sentence. Jones,
846 F.3d at 372. Instead, we “defer to the district court’s
judgment when,” as here, “it has presented a ‘reasoned and
reasonable decision that the § 3553(a) factors, on the whole,
justified the sentence.’” United States v. Ventura, 650 F.3d 746,
751 (D.C. Cir. 2011) (quoting Gall, 552 U.S. at 59-60). Given
the district court’s extensive consideration of the statutory
factors and the reasoned explanation of its decision, the court
did not abuse its discretion by imposing a sentence at the
bottom of the Guidelines range. See Fry, 851 F.3d at 1333-34
(affirming as substantively reasonable a within-Guidelines
sentence for a child-pornography offender based on the
seriousness of the conduct and the need for adequate
deterrence).

                               V

     For the foregoing reasons, we affirm the sentence imposed
by the district court.

                                                    So ordered.
