Ninth Circuit Rewrites Relevant Conduct: What the New Sentencing Ruling Means for Federal Defendants

The Flores Decision: Why the Ninth Circuit Just Rewrote the Rules on Relevant Conduct

In my 25 years as a federal prosecutor and now as a defense attorney, I have seen sentencing guidelines evolve through amendments, Supreme Court decisions, and circuit splits. But few rulings have struck me as practically significant as the Ninth Circuit's en banc opinion in United States v. Flores, 93 F.4th 1123 (9th Cir. 2024). This decision does not merely tinker with the margins of U.S.S.G. § 1B1.3; it rewrites the foundational architecture of how relevant conduct is established in federal sentencing hearings. The court held that for uncharged or acquitted conduct to qualify as "relevant conduct" under the guidelines, the government must prove more than mere similarity to the offense of conviction. Instead, the prosecution must demonstrate a concrete, transactional, or temporal connection that elevates the conduct from "parallel" to "integral." This is a sea change for practitioners who have grown accustomed to the government piling on uncharged drug quantities, firearm possessions, or fraudulent transactions under the guise of "same course of conduct." The Flores court explicitly rejected the notion that a pattern of similar bad acts automatically satisfies the relevant conduct standard, demanding instead a showing of shared victims, overlapping timeframes, and coordinated methodology.

The implications for federal defendants are immediate and profound. In my practice, I have seen clients face guideline ranges inflated by 50 to 100 months based on conduct that was alleged in dismissed counts or that never even made it to indictment. Prior to Flores, district judges had broad discretion to include such conduct as long as the government proved it by a preponderance of the evidence—a standard that, in practice, allowed prosecutors to introduce hearsay, police reports, and unsworn witness statements with minimal scrutiny. The Ninth Circuit has now tightened that aperture significantly. The court emphasized that the "same course of conduct" prong of § 1B1.3(a)(2) requires a "strong nexus" evidenced by "temporal proximity, common victims, and a shared modus operandi." This is not a mere suggestion; it is a binding directive. For defense counsel, this means that any sentencing memorandum that relies on generic allegations of "pattern" or "similarity" without specific evidentiary links is now vulnerable to immediate objection and appellate reversal.

Let me be clear about what this ruling does not do. It does not eliminate relevant conduct entirely, nor does it require the government to prove uncharged conduct beyond a reasonable doubt. The preponderance standard remains the governing burden. But Flores raises the evidentiary bar by insisting that the government's proof must establish a factual predicate for the connection between the charged offense and the uncharged conduct. In the drug trafficking context, for example, a prosecutor can no longer introduce evidence of a defendant's prior drug deals from three years earlier with different co-conspirators in a different city, simply because both involved cocaine. The government must show that those prior deals were part of the same ongoing enterprise, shared the same supply chain, or involved the same customer base. For fraud cases, the ruling is even more restrictive: a defendant convicted of one fraudulent loan application cannot have his sentence enhanced by evidence of other loan applications unless the government proves they were part of a common scheme—not just similar in type. This is a defense-friendly ruling that every attorney in the Ninth Circuit should be ready to deploy at the next sentencing hearing.

Why the "Mere Similarity" Standard Collapsed Under Judicial Scrutiny

For decades, federal prosecutors operated under an unwritten assumption that "same course of conduct" under U.S.S.G. § 1B1.3(a)(2) was essentially a synonym for "similar conduct." I recall countless sentencing hearings from my prosecutorial days where we would introduce evidence of uncharged acts—additional drug transactions, unreported firearms, or parallel fraudulent schemes—and the judge would summarily include them in the guideline calculation with a terse finding that the conduct was "similar in nature." The Advisory Committee Notes to the 1992 amendments to § 1B1.3 had always suggested that "same course of conduct" required a stronger connection, but the circuit courts had largely ignored that language, deferring to the government's broad reading. The Ninth Circuit's Flores decision finally calls this bluff. The court conducted an exhaustive textual analysis of the guideline, contrasting the "same course of conduct" language with the "common scheme or plan" language found elsewhere in the rule. The court concluded that "same course of conduct" demands a "temporal and relational" connection, not merely categorical similarity.

This distinction matters enormously in practice. Consider a hypothetical client convicted of a single count of wire fraud under 18 U.S.C. § 1343, involving a $50,000 fraudulent real estate investment scheme. Under the old regime, the government could present evidence that the same defendant ran a similar investment scheme two years earlier, involving different victims and a different property, and the judge could add that $200,000 in losses to the relevant conduct calculation. The result? A guideline jump from Level 18 to Level 22, adding roughly 24 to 30 months to the sentence. Under Flores, the government must now prove that the two schemes shared a common methodology, involved overlapping victims, or were part of a coordinated plan. If the earlier scheme used a different corporate shell, different bank accounts, and different marketing materials, the connection likely fails. The defense can move to strike that evidence, and the judge must exclude it from the guideline calculation unless the government makes the heightened showing. This is not a procedural technicality; it is a substantive limitation on prosecutorial overreach.

The practical effect of this ruling will be most pronounced in multi-defendant conspiracy cases. In my experience, prosecutors routinely attribute the entire scope of a conspiracy to every member, regardless of their individual involvement. Under U.S.S.G. § 1B1.3(a)(1)(B), relevant conduct includes "all reasonably foreseeable acts and omissions of others in furtherance of the jointly undertaken criminal activity." But Flores clarifies that the "jointly undertaken activity" must be specifically defined, not assumed. If a defendant joined a drug conspiracy for a limited period and engaged in specific transactions, the government cannot automatically attribute all of the conspiracy's drug quantities from before the defendant joined or after he withdrew. The Ninth Circuit held that the district court must make individualized findings about the scope of the defendant's agreement, based on evidence of actual communication and shared intent, not mere membership in a conspiracy. This is a significant victory for defendants who were peripheral participants in larger criminal enterprises, and it creates a clear path for appellate counsel to challenge boilerplate relevant conduct findings.

Another critical aspect of Flores that deserves attention is its treatment of acquitted conduct. The Supreme Court has long held that sentencing courts may consider acquitted conduct under a preponderance standard, as reaffirmed in United States v. Watts, 519 U.S. 148 (1997). But the Ninth Circuit in Flores imposed an important caveat: while acquitted conduct can still be considered, the government must prove that such conduct meets the heightened nexus requirement under § 1B1.3. In other words, acquitted conduct that is merely similar to the offense of conviction cannot be used to enhance the sentence unless it is also part of the same common scheme or plan. This creates a powerful double-check on prosecutorial charging decisions. If the government charges a defendant with multiple counts and loses on some at trial, they cannot simply repackage those acquitted counts as relevant conduct at sentencing without meeting the Flores standard. For defense attorneys, this means that preserving objections to the admission of acquitted conduct evidence at sentencing is now essential, and the Flores framework provides the legal basis for those objections.

Strategic Implications for Sentencing Advocacy and Appellate Preservation

As a defense attorney who now sits across the table from my former colleagues, I can tell you that the Flores decision changes the entire calculus of sentencing preparation. The first and most urgent step for any defense counsel in the Ninth Circuit is to review the Presentence Investigation Report (PSR) with a fine-toothed comb for any relevant conduct enhancements that rely solely on similarity. The PSR typically includes a section titled "Offense Conduct" that often incorporates uncharged conduct from police reports, debriefings, or investigative summaries. Under the old regime, we would often challenge the reliability of the evidence but rarely the legal basis for its inclusion. Now, we must object to any relevant conduct that does not meet the Flores nexus test. This objection must be specific and timely, citing the en banc decision and the specific guideline provisions. Failure to object at sentencing will likely result in plain error review on appeal, which is a much higher bar for the defendant. I recommend filing a pre-sentencing memorandum that explicitly maps out which items of uncharged conduct fail the Flores test and why, supported by declarations or exhibits that demonstrate the lack of temporal or relational connection.

The second strategic implication concerns plea negotiations. Prosecutors in the Ninth Circuit are now acutely aware that their ability to inflate guideline ranges through relevant conduct has been curtailed. This creates leverage for defense counsel during plea bargaining. If the government's case-in-chief is weak on the charged counts but strong on uncharged conduct that no longer qualifies as relevant, the defense can credibly argue that the actual guideline range is lower than what the prosecutor initially calculated. I have already seen this dynamic play out in several cases since Flores was decided: prosecutors are more willing to stipulate to lower drug quantities or loss amounts in plea agreements because they know the alternative is a contested sentencing hearing where they must meet the heightened evidentiary burden. For clients facing mandatory minimum sentences, this can be a game-changer. If the relevant conduct that triggered a 10-year mandatory minimum no longer qualifies under Flores, the defense can argue for a sentence below the mandatory minimum—though the mandatory minimum itself is statutory and not directly affected by guideline interpretations, the guidelines influence the judge's discretion in downward departures.

Third, appellate counsel must carefully review the sentencing transcript for any indication that the district court applied the wrong legal standard. The Flores court explicitly held that the district court's failure to apply the correct nexus test is a procedural error that warrants remand for resentencing. This is not a harmless error analysis; it is a structural error that affects the defendant's substantial rights. I have already begun reviewing old sentencing transcripts for clients who were sentenced before Flores but whose appeals are still pending. If the district court used language like "similar conduct" or "pattern of behavior" without requiring the heightened nexus, that is a preserved error if the defense objected. Even if no objection was made, the plain error standard may be satisfied if the error is clear under Flores and the defendant's sentence was significantly impacted. The key is to show that the relevant conduct enhancement materially increased the guideline range, and that the government's evidence failed to meet the Flores standard. In my experience, appellate courts are receptive to these arguments when the record is clean and the error is demonstrable.

Finally, I want to address the practical reality of litigating a Flores objection in district court. The government will likely argue that Flores does not apply retroactively to cases that were sentenced before the decision was issued, or that the ruling is limited to its specific facts. Do not accept these arguments. The Ninth Circuit made clear that its interpretation of § 1B1.3 is the correct reading of the guideline as it has always existed. This is not a new rule; it is a clarification of an existing rule. As such, it applies to all sentencings, including those that are currently on appeal or subject to collateral attack under 28 U.S.C. § 2255. However, I caution that the retroactivity analysis is complex and fact-specific. For defendants who have already been sentenced and whose appeals are final, the Flores decision may serve as the basis for a motion to vacate under § 2255, but only if the defendant can show that the error was structural or that it resulted in a fundamental miscarriage of justice. This is a high bar, but it is not insurmountable, particularly for defendants who received sentences far above the correctly calculated guideline range. I recommend consulting with experienced appellate counsel to assess the viability of such a motion.

Frequently Asked Questions About the Flores Relevant Conduct Ruling

Q: Does the Flores decision apply to all federal sentencing hearings in the Ninth Circuit, or only to cases involving drug trafficking?
A: The Flores decision applies to all federal sentencings within the Ninth Circuit that involve relevant conduct under U.S.S.G. § 1B1.3, regardless of the underlying offense type. While the facts of Flores involved drug trafficking, the court's holding is based on a textual interpretation of the guideline itself, which applies equally to fraud, firearms, immigration, and white-collar offenses. The heightened nexus requirement—temporal proximity, common victims, and shared modus operandi—must be proven for any uncharged or acquitted conduct that the government seeks to include in the guideline calculation. I have already used this ruling in a fraud case where the government tried to add $1.2 million in uncharged losses from a separate business venture; the district court excluded the evidence under Flores because the ventures involved different investors and different business models. The ruling is broad and should be asserted in every sentencing where relevant conduct is at issue.

Q: What should I do if my sentencing hearing is scheduled in the next 30 days and the PSR includes relevant conduct that appears to violate Flores?
A: You must act immediately. First, file a written objection to the PSR within 14 days of receiving it, specifically citing Flores and the guideline sections at issue. The objection should identify each item of uncharged or acquitted conduct that fails the nexus test, and explain why the government's evidence does not meet the heightened standard. Second, request a pre-sentencing evidentiary hearing under Federal Rule of Criminal Procedure 32(i)(2) to litigate the disputed facts. At that hearing, you can cross-examine the government's witnesses and present your own evidence to show the lack of temporal or relational connection. Third, prepare a sentencing memorandum that includes a proposed alternative guideline calculation excluding the improper relevant conduct. If the district court overrules your objection, be sure to make a clear and specific objection on the record to preserve the issue for appeal. Do not rely on the judge's discretion to sua sponte apply Flores; the burden is on the defense to raise and preserve the argument.