Emphasizing Offense Seriousness in Statutory-Maximum, Within-Guidelines Sentences: Commentary on United States v. Campbell (6th Cir. 2025)

I. Introduction

This commentary analyzes the Sixth Circuit's unpublished decision in United States v. Jason Campbell, No. 25-5477 (6th Cir. Nov. 24, 2025), in which the court affirmed a 480-month (40-year) sentence imposed on a repeat sex offender convicted of producing and possessing child pornography in violation of 18 U.S.C. §§ 2251(a) and 2252(a)(4)(B).

The central issue on appeal was the substantive reasonableness of the sentence. Campbell argued that the district court abused its discretion by placing an “unreasonable amount of weight” on the nature and seriousness of his offense in imposing the highest possible sentence permitted by statute, even though that sentence fell within the United States Sentencing Guidelines (“Guidelines”) range.

The Sixth Circuit, applying its well-established presumption of reasonableness for within-Guidelines sentences and a deferential abuse-of-discretion standard, rejected this argument and affirmed. The opinion does not announce a radical new doctrine, but it meaningfully reinforces and illustrates several recurring principles in federal sentencing law, particularly that:

• A within-Guidelines sentence—even at the statutory maximum—carries a strong presumption of substantive reasonableness.
• A district court may place heavy emphasis on the seriousness of the offense and the need to protect the public, especially in cases involving repeat sexual abuse of minors, so long as it acknowledges and considers the other 18 U.S.C. § 3553(a) factors and the mitigating evidence.
• Expressing that the statutory maximum “would not be sufficiently high” to provide just punishment does not render the resulting sentence arbitrary if the court still adheres to the Guidelines and carefully explains its reasoning.

Although “not recommended for publication” and thus non-precedential, the decision provides a clear, instructive application of Sixth Circuit sentencing principles to a fact pattern that often gives rise to appeals: a statutory-maximum sentence within the Guidelines in a serious child-exploitation case involving a repeat offender.

II. Summary of the Opinion

Jason Campbell pled guilty to:

• Count 3: Production of child pornography, 18 U.S.C. § 2251(a); and
• Count 4: Possession of child pornography, 18 U.S.C. § 2252(a)(4)(B).

The offenses involved repeated sexual abuse of a 14-year-old girl, M.Y., who was his girlfriend’s daughter and under his care. Police discovered images and videos on Campbell’s phone documenting the abuse. He was also a repeat sex offender, having previously been convicted in 2010 in Kentucky state court for sexually abusing another minor under 12 years old over a period of several years (2002–2007).

Applying the Guidelines, the district court calculated an overall offense level of 40, which—combined with Campbell’s criminal history—yielded an advisory range of 360 months to life. However, because the statutory maximums were 30 years for § 2251(a) and 10 years for § 2252(a)(4)(B), the effective Guidelines range became 360 to 480 months.

After hearing mitigation arguments and a government request for the maximum, the district court concluded that:

• The statutory maximum “would not be sufficiently high enough” to provide just punishment, given the gravity and duration of the abuse and Campbell’s prior sex offense.
• The seriousness of the offense, the need to protect the public, deterrence, promotion of respect for law, and just punishment all strongly supported a very lengthy sentence.
• While it considered Campbell’s mitigation (poverty, drug history, GED, acceptance of responsibility, sparing the victim from testifying), these factors did not justify a lower sentence in light of his history and conduct.

The district court imposed a sentence of 480 months, the statutory maximum and top of the Guidelines range.

On appeal, Campbell argued that this sentence was substantively unreasonable because the district court placed excessive weight on the nature and circumstances of the offense. The Sixth Circuit rejected this argument, holding:

1. The sentence, being within the Guidelines range, is presumptively reasonable under United States v. Vonner.
2. The record showed a careful, reasoned application of the § 3553(a) factors—seriousness of the offense, criminal history, protection of the public, deterrence, and consideration of mitigation.
3. It is not substantively unreasonable for a court to emphasize one factor (here, seriousness of the offense) more than others, so long as all are considered, citing United States v. Rayyan and United States v. Zobel.
4. Unlike cases where within-Guidelines sentences have been found unreasonable due to a complete failure to address § 3553(a) or mitigation (e.g., United States v. Delgadillo), the district court here adequately explained its reasoning.

Concluding that the district court did not abuse its discretion and that the sentence was “proportionate to the seriousness of the circumstances” and “sufficient but not greater than necessary” to fulfill § 3553(a)’s purposes, the Sixth Circuit affirmed the sentence.

III. Detailed Analysis

A. Factual and Procedural Background

The case arose when, on May 24, 2024, the victim’s mother, Janie Castle, reported Campbell to the Johnson County, Kentucky Department of Social Services for engaging in sexual contact with her 14-year-old daughter, M.Y. Law enforcement:

• Arrested Campbell;
• Seized his phone; and
• Recovered multiple images and videos of child sexual abuse, including depictions of Campbell abusing M.Y.

M.Y. reported that Campbell had been sexually abusing her for several years, suggesting prolonged and repeated abuse. This pattern was particularly significant in light of Campbell’s earlier conviction for first-degree sexual abuse of another minor, for which he received a one-year sentence in 2010.

In June 2024, a federal grand jury indicted Campbell on four counts related to the production of child pornography. In February 2025, he pled guilty to two counts:

• Production of child pornography, 18 U.S.C. § 2251(a) (Count 3); and
• Possession of child pornography, 18 U.S.C. § 2252(a)(4)(B) (Count 4).

The government dismissed the remaining two counts as part of the plea agreement.

Guidelines Calculations

The district court methodically explained its Guidelines calculations:

1. Count 3 – Production (§ 2251(a))
   Applied U.S.S.G. § 2G2.1 (Sexual Exploitation of a Minor):
   • Base offense level: 32 (§ 2G2.1(a)).
   • +2 because the victim was under 16.
   • +2 because the offense involved the commission of a sexual act.
   • +2 because the victim was under defendant’s care.
   • Adjusted offense level for Count 3: 38.
2. Count 4 – Possession (§ 2252(a)(4)(B))
   Because the conduct involved “causing a minor to engage in sexually explicit conduct for the purpose of producing a visual depiction,” U.S.S.G. § 2G2.2(c)(1) directed the court to apply § 2G2.1 again:
   • Same base level (32) and the same three enhancements (+2, +2, +2).
   • Adjusted offense level for Count 4: 38.
3. Grouping
   Because both counts involved the same victim and the same general course of conduct, they were grouped under the Guidelines’ grouping rules, resulting in:
   • Group offense level: 38.
4. Adjustments
   The court then applied:
   • −3 for acceptance of responsibility, acknowledging Campbell’s guilty plea and cooperation (U.S.S.G. § 3E1.1), and
   • +5 for a pattern of prohibited sexual conduct with the victim, reflecting repeated acts (consistent with U.S.S.G. § 4B1.5(b)(1) for “Repeat and Dangerous Sex Offender Against Minors”).
   Producing a final:
   • Total offense level: 40.

Based on the total offense level and Campbell’s criminal history (which included a prior sex offense), the advisory Guidelines range under Chapter 5, Part A was calculated as 360 months to life.

Interaction with Statutory Maximums

The applicable statutory maximum penalties were:

• 30 years (360 months) for § 2251(a) (production); and
• 10 years (120 months) for § 2252(a)(4)(B) (possession).

When sentences run consecutively or concurrently across multiple counts, the Guidelines incorporate the limitations imposed by statutory maximums. Here, the combined statutory maximum term of imprisonment across both counts was 40 years (480 months).

As a result, although the Guidelines range abstractly extended to life, the effective range under the applicable statutory caps became:

360 months to 480 months.

Campbell conceded that this Guidelines calculation was correct. His appeal was therefore limited to the substantive reasonableness of the particular sentence chosen within that range.

B. The Sentencing Framework: § 3553(a) and the Court’s Explanation

The district court explicitly invoked 18 U.S.C. § 3553(a), which requires consideration of:

• The nature and circumstances of the offense;
• The history and characteristics of the defendant;
• The need for the sentence to:
  • reflect the seriousness of the offense,
  • promote respect for the law,
  • provide just punishment,
  • afford adequate deterrence,
  • protect the public from further crimes of the defendant, and
  • provide the defendant with needed educational or vocational training, medical care, or other correctional treatment;
• The kinds of sentences available;
• The Guidelines range;
• Any pertinent policy statements;
• The need to avoid unwarranted sentencing disparities; and
• The need to provide restitution to victims.

The district judge:

• Acknowledged mitigation:
  • Campbell’s impoverished upbringing;
  • Death of his ex-wife from a drug overdose;
  • His own history of methamphetamine abuse;
  • His completion of a GED and work skills;
  • His acceptance of responsibility and the fact that he spared the victim the trauma of testifying at trial.
• Emphasized aggravation:
  • His prior conviction for first-degree sexual abuse of a minor under 12;
  • The lengthy period of abuse of M.Y.;
  • The severe, “true harm” inflicted on the victim;
  • The need to protect the public from a demonstrably dangerous repeat offender.
• Concluded that the statutory maximum “would not be sufficiently high” to provide just punishment given the seriousness of the offense and his recidivism, yet remained bound by the Guidelines and statutory caps.

On that basis, the court selected a sentence at the top end of the effective Guidelines range: 480 months.

C. Precedents Cited and Their Influence

The Sixth Circuit’s opinion is tightly integrated into its preexisting sentencing jurisprudence. The panel invokes several prior decisions to frame the standard of review and to delineate when a within-Guidelines sentence may nevertheless be substantively unreasonable.

1. United States v. Robinson, 813 F.3d 251 (6th Cir. 2016)

Robinson is cited for the proposition that challenges to the substantive reasonableness of a sentence are reviewed under an abuse-of-discretion standard. That standard is:

• Highly deferential to the district court;
• Focused on whether the court gave “reasonable” weight to the relevant factors;
• Not a license for the appellate court to substitute its own judgment for that of the sentencing judge.

In Campbell, this sets the overarching framework: the panel asks whether the district court’s decision to impose 480 months, within the advisory range, lies within the broad zone of permissible outcomes, rather than whether the appellate judges might themselves have preferred a lower (or higher) sentence.

2. United States v. Vonner, 516 F.3d 382 (6th Cir. 2008) (en banc)

Vonner is a cornerstone of Sixth Circuit sentencing law. Here it is cited for its holding that within-Guidelines sentences are presumptively reasonable on appellate review. That presumption:

• Does not bind the district court; it only applies on appeal.
• Reflects Congress’s and the Sentencing Commission’s considered view of appropriate sentencing ranges.
• Places the burden on the defendant to rebut that presumption by demonstrating that, in the particular circumstances of his case, the sentence is greater than necessary to achieve § 3553(a)’s goals.

In Campbell, the panel invokes Vonner to state that Campbell’s 480-month sentence, being within the effective Guidelines range of 360–480 months, is presumptively reasonable. From there, the court asks whether anything in the district court’s reasoning overcomes that presumption. It concludes nothing does.

3. United States v. Simmons, 587 F.3d 348 (6th Cir. 2009)

Simmons is cited to reinforce the deferential nature of substantive reasonableness review. The reference underscores that appellate courts do not lightly second-guess district judges who:

• Cite and apply the § 3553(a) factors;
• Address or at least acknowledge mitigation;
• Remain within the advisory Guidelines range.

In Campbell, the district court did all of these, making reversal under Simmons highly unlikely.

4. United States v. Solano-Rosales, 781 F.3d 345 (6th Cir. 2015) and United States v. Vowell, 516 F.3d 503 (6th Cir. 2008)

These cases provide the definition of substantive reasonableness adopted in the opinion:

A sentence is substantively reasonable if it is “proportionate to the seriousness of the circumstances of the offense and offender, and sufficient but not greater than necessary, to comply with the purposes of § 3553(a).”

The phrase “sufficient but not greater than necessary” comes directly from § 3553(a) and is sometimes called the parsimony principle.

In Campbell, the panel applies this definition to conclude that a 40-year sentence is proportionate to:

• The gravity and duration of Campbell’s abuse of M.Y.;
• His prior sexual abuse of a different minor; and
• The need to protect the public and deter future wrongdoing.

5. United States v. Delgadillo, 318 F. App’x 380 (6th Cir. 2009)

Delgadillo is the key counterexample—a case where the Sixth Circuit actually found a within-Guidelines sentence substantively unreasonable.

There, the district court:

• Imposed a sentence at the bottom of the Guidelines;
• But essentially failed to discuss the § 3553(a) factors;
• And did not meaningfully address the defendant’s extensive mitigation.

The court reversed, holding that even a within-Guidelines sentence can be unreasonable where the sentencing judge effectively abdicates the duty to consider the statutory factors or to explain the sentence.

In Campbell, the panel contrasts the case before it with Delgadillo. Unlike in Delgadillo, the sentencing judge here:

• Methodically walked through the § 3553(a) factors;
• Discussed both aggravating and mitigating circumstances;
• Gave a clear rationale emphasizing offense seriousness, criminal history, public protection, and deterrence.

This comparison demonstrates the Sixth Circuit’s implicit rule: within-Guidelines sentences will almost always be affirmed when accompanied by a reasoned, factor-based explanation, even if the judge strongly emphasizes aggravating factors such as offense seriousness.

6. United States v. Rayyan, 885 F.3d 436 (6th Cir. 2018)

Rayyan provides one of the Sixth Circuit’s clearest articulations of the sentencing court’s discretion in weighing the § 3553(a) factors. It states:

“Weighing the § 3553(a) factors is a matter of reasoned discretion, not math.”

In other words:

• The court is not required to give equal weight to each factor;
• It may give greater emphasis to certain considerations (e.g., seriousness of the offense, protection of the public) so long as:
  • All relevant factors are at least considered; and
  • The resulting sentence is within the overall bounds of reasonableness.

Campbell relies on Rayyan to reject the defendant’s argument that the district court placed “too much” weight on the seriousness of the offense. The panel explains that there is no rigid formula dictating how heavily each factor must weigh.

7. United States v. Zobel, 696 F.3d 558 (6th Cir. 2012)

Zobel similarly affirms that a district court may highlight certain § 3553(a) factors over others, provided the overall analysis remains grounded in the statute and facts.

In the context of Campbell, Zobel supports the idea that, in a case involving prolonged sexual exploitation of a minor and prior sexual abuse, the court was entitled to give primacy to:

• The nature and circumstances of the offense;
• The need to protect the public;
• The need for just punishment and deterrence.

8. United States v. Young, 847 F.3d 328 (6th Cir. 2017)

The panel quotes Young to underscore a key point:

“[A]lthough the court was clearly concerned with the nature and seriousness of the offenses, it also considered other § 3553(a) factors [and] fashioned a sentence that reflected those factors.”

This passage mirrors what the panel finds in the record of Campbell. The citation signals that the court views the sentencing judge’s approach as squarely within the mainstream of Sixth Circuit sentencing practice.

D. The Court’s Legal Reasoning on Substantive Reasonableness

The Sixth Circuit’s analysis can be distilled into several logical steps.

1. Presumption of Reasonableness and Standard of Review

First, the court:

• Applies the presumption of reasonableness for within-Guidelines sentences under Vonner;
• Notes that its review is under an abuse-of-discretion standard (Robinson, Simmons).

This means that, from the outset, Campbell must overcome a strong appellate presumption in favor of his sentence. He must show that the district court’s weighing of the § 3553(a) factors is outside the range of reasonable outcomes, not simply that a lower sentence could also have been justified.

2. Adequate Consideration of § 3553(a) and Mitigation

Second, the panel examines the record to see whether the sentencing judge:

• Identified and discussed the § 3553(a) factors;
• Gave the parties an opportunity to present arguments;
• Addressed or acknowledged the mitigating evidence presented by the defense.

It finds that the district court:

• Explicitly walked through multiple § 3553(a) factors;
• Heard and acknowledged Campbell’s mitigation arguments; and
• Still found that his criminal history and the seriousness and duration of his offenses demanded a very lengthy sentence.

This detailed record sharply distinguishes the case from Delgadillo, where the absence of such discussion justified reversal.

3. Emphasis on Offense Seriousness Is Permissible

Campbell’s core appellate argument—that the district court put an “unreasonable amount of weight” on offense seriousness—is directly addressed through Rayyan and Zobel. The panel’s reasoning is:

• The law does not require “equal” or “balanced” weight across all § 3553(a) factors.
• A sentencing judge may reasonably emphasize the seriousness of the offense, especially in egregious cases involving:
  • Long-term exploitation of a minor;
  • Production and possession of child pornography;
  • Recidivist sexual offending.
• So long as the judge acknowledges other factors and explains the decision, an emphasis on seriousness does not render the sentence “arbitrary” or “greater than necessary.”

The panel finds that the district court did precisely what Sixth Circuit law endorses: it consciously weighed the gravity of the offense and the need for protection of the public more heavily than mitigation, and explained why.

4. Proportionality to the Offense and Offender

Applying Solano-Rosales and Vowell, the court next evaluates whether the sentence is:

• Proportionate to the seriousness of the offense and offender; and
• “Sufficient but not greater than necessary” to achieve § 3553(a)’s purposes.

The panel concludes that 480 months is proportionate because:

• Campbell repeatedly abused a young teenager under his care for a prolonged period.
• He documented the abuse, contributing to the production and possession of child sexual exploitation material.
• He had previously been convicted of sexually abusing another minor over a period of years.
• The judge reasonably doubted whether anything less than the maximum allowed would adequately protect the public and provide sufficient deterrence and punishment.

Against this backdrop, the mitigating factors—while real—were not so weighty as to render a 40-year sentence excessive in the Sixth Circuit’s view.

5. No Error in Maximizing a Within-Guidelines Range

Finally, the court rejects any suggestion that selecting the top of the Guidelines range is, by itself, suspect. The fact that:

• The Guidelines range already accounted for many aggravating factors;
• Yet still recommended a range as high as life;
• And that the statutory maximum capped the sentence at 40 years;

underscores, in the panel’s view, that selecting 480 months is a legitimate exercise of discretion: the district court stayed within both the Guidelines and statutory boundaries, and chose a point in the range well supported by the specific facts of the case.

E. Child-Exploitation Offenses and Recidivism: The Context of the Decision

While the opinion does not dwell on policy debates, it fits squarely within broader trends in federal sentencing of child-exploitation offenses, particularly:

• Severe Guidelines and statutory penalties for production and possession of child pornography.
• Special concern for recidivist sex offenders, as reflected in:
  • Criminal history scoring;
  • The pattern-of-activity enhancement;
  • Judicial emphasis on public safety and deterrence.

The district court’s comment that the statutory maximum might not be “sufficiently high” shows the strong institutional concern with:

• Long-term community protection from known repeat offenders;
• Serious psychological and developmental harm to child victims;
• The permanent nature of recorded sexual abuse images.

In affirming the maximum sentence, the Sixth Circuit signals that, in cases of:

• Repeated hands-on sexual abuse;
• Creation and possession of exploitative images;
• Prior sexual-offense history;

a statutory-maximum, within-Guidelines sentence will almost certainly be upheld so long as the district court:

• Explains its reasoning through § 3553(a); and
• Acknowledges, even if it ultimately discounts, mitigating evidence.

F. Impact and Future Implications

Although unpublished, United States v. Campbell has several practical implications for sentencing practice and appeals in the Sixth Circuit.

1. Strengthening the Presumption for Maximum Within-Guidelines Sentences

The decision confirms that the presumption of reasonableness applies with full force even when:

• The sentence is the statutory maximum; and
• It is at the top end of the Guidelines range.

Defendants challenging such sentences on substantive reasonableness grounds will face a formidable hurdle, particularly in serious child-exploitation cases with prior sexual offenses.

2. Legitimizing Heavy Emphasis on Offense Seriousness

The opinion concretely illustrates the Sixth Circuit’s view that:

• A district court may heavily emphasize the seriousness of the offense, the harm to the victim, and the need to protect the public;
• So long as the judge acknowledges and considers other factors, including mitigation, substantive reasonableness is not undermined.

Defense attorneys should therefore expect that arguments complaining that the court “overweight” seriousness will seldom succeed unless the record shows:

• Neglect of other § 3553(a) factors; or
• A sentence so extreme, relative to the facts and Guidelines, that it appears arbitrary.

3. Importance of a Detailed Sentencing Explanation

The contrast with Delgadillo underscores a practical rule:

• Where the district court provides a detailed explanation of the sentence, touching on § 3553(a) and mitigation, within-Guidelines sentences will be almost unassailable on appeal.
• Reversal becomes thinkable only when there is:
  • A complete failure to consider or discuss key factors; or
  • Clear evidence that the court ignored important mitigation without explanation.

Campbell thus serves as a template for district judges: walking through the key factors on the record is the best insulation against appellate reversal.

4. Limited Space for Substantive Reasonableness Challenges in Similar Cases

In serious child-exploitation cases involving:

• Hands-on abuse;
• Production and possession of exploitative images;
• Recidivist conduct;

Campbell suggests that the Sixth Circuit will routinely find lengthy, even maximum, sentences to be substantively reasonable. The opinion reaffirms that the appellate role is not to fine-tune sentencing calibrations in such cases, but to police for truly out-of-bounds decisions or failures of explanation.

IV. Complex Concepts Simplified

Several legal concepts are central to understanding the opinion. The following explanations are designed for non-specialists.

1. Substantive vs. Procedural Reasonableness

• Procedural reasonableness asks: Did the judge follow the right steps?
  • Correctly calculated the Guidelines;
  • Considered the § 3553(a) factors;
  • Allowed both sides to be heard;
  • Explained the sentence.
• Substantive reasonableness asks: Is the sentence too long or too short, given the facts and purposes of sentencing?
  • This is about the fairness of the outcome, not the process.

In Campbell, only substantive reasonableness was at issue, because Campbell agreed the Guidelines calculation was correct and did not raise procedural objections.

2. Abuse-of-Discretion Standard

When an appellate court reviews for abuse of discretion, it:

• Gives substantial deference to the trial judge’s decision;
• Will not reverse just because it might have decided differently;
• Intervenes only when the sentence falls outside the range of reasonable outcomes, or is based on a serious error in judgment or law.

This is a highly deferential standard, especially when combined with the presumption of reasonableness for within-Guidelines sentences.

3. The Sentencing Guidelines and “Within-Guidelines” Sentences

The U.S. Sentencing Guidelines are advisory rules that suggest a range of months of imprisonment based on:

• The offense level (determined by the type of crime and any aggravating or mitigating characteristics, such as use of violence, number of victims, or acceptance of responsibility); and
• The defendant’s criminal history category.

A sentence that falls inside this recommended range is called a within-Guidelines sentence and is presumed reasonable on appeal in the Sixth Circuit.

4. Statutory Maximum

A statutory maximum is the highest sentence Congress allows for a particular crime. Even if the Guidelines suggest a higher sentence (e.g., “life”), the judge cannot exceed the statutory maximum.

In Campbell:

• The Guidelines range was 360 months to life;
• But the total statutory maximum across both counts was 480 months;
• Thus, the effective Guidelines range became 360–480 months.

5. 18 U.S.C. § 3553(a) Factors

These are the statutory factors the judge must consider in deciding what sentence to impose. They include:

• Seriousness of the offense;
• Protection of the public;
• Deterrence (discouraging crime);
• Just punishment and respect for the law;
• The defendant’s background, character, and circumstances;
• The advisory Guidelines range; and
• Restitution and avoidance of unwarranted disparities.

No single factor is automatically controlling; the judge must balance them, but may give more weight to some than others, as long as the overall decision is reasonable.

6. Pattern-of-Activity and Repeat Sex Offender Enhancements

The Guidelines treat repeat sexual misconduct against minors as especially serious. A “pattern of activity” or “repeat and dangerous sex offender” enhancement can significantly increase the offense level when:

• There are multiple incidents of prohibited sexual conduct; and/or
• The defendant has prior convictions for sex offenses involving minors.

In Campbell, the +5 enhancement reflected a pattern of prohibited sexual conduct, which, combined with his prior conviction, painted a picture of a dangerous recidivist.

V. Conclusion

United States v. Campbell reinforces core principles of Sixth Circuit sentencing law:

• Within-Guidelines sentences, including those at the statutory maximum, are presumptively reasonable on appeal.
• A district court may legitimately place substantial weight on the seriousness of the offense and the need to protect the public, especially in cases involving:
  • Long-term sexual abuse of a minor;
  • Production and possession of child pornography;
  • Prior sexual offenses against minors.
• Appellate courts will defer to the sentencing judge’s reasoned discretion in weighing the § 3553(a) factors, so long as the record shows that:
  • All relevant factors were considered; and
  • The judge addressed, even if rejected, the defense’s mitigating evidence.
• Within-Guidelines sentences will be overturned as substantively unreasonable only in exceptional circumstances, such as a complete failure to engage with the § 3553(a) factors or to explain the sentence (Delgadillo), circumstances not present here.

While unpublished and non-binding, the opinion in Campbell is a clear exposition of how the Sixth Circuit approaches maximum, within-Guidelines sentences in serious child-exploitation cases. It affirms that so long as district courts articulate a thorough, factor-based rationale, even the harshest sentences authorized by law will generally withstand substantive reasonableness review on appeal.