Rehaif Rendered Ruan-Based § 841 Mens Rea Claims “Reasonably Available,” Defeating “Cause” for Procedural Default

Case: United States v. Okechukwu Dimkpa (4th Cir. Mar. 3, 2026)  |  Court: United States Court of Appeals for the Fourth Circuit  |  Disposition: Affirmed

I. Introduction

This published Fourth Circuit decision addresses a recurring post-Ruan question: when a physician pleaded guilty to unlawful distribution under 21 U.S.C. § 841(a)(1) before Ruan v. United States clarified the statute’s mens rea requirement, can the physician later obtain collateral relief under 28 U.S.C. § 2255 despite not raising the issue at plea, sentencing, or on direct appeal?

The appellant, Dr. Okechukwu Dimkpa, pleaded guilty in 2019 to six counts of unlawfully distributing oxycodone. The plea colloquy reflected then-controlling Fourth Circuit law, which treated authorization largely through an objective “usual course of professional practice” lens and did not require proof that the doctor knew he was acting without authorization. In 2022, Ruan v. United States held that to convict under § 841, the government must prove the physician “knowingly or intentionally acted in an unauthorized manner.” Dr. Dimkpa filed a § 2255 motion arguing his plea was not knowing and voluntary because he had not been informed of the Ruan mens rea element.

The core issue on appeal was procedural: whether Dr. Dimkpa could show “cause” to excuse procedural default of his Ruan-based claim—specifically, whether the claim was so “novel” in 2019 that its legal basis was not “reasonably available.”

II. Summary of the Opinion

The Fourth Circuit affirmed denial of § 2255 relief on procedural default grounds. While acknowledging that Ruan changed the law in the Fourth Circuit, the court held Dr. Dimkpa could not establish “cause” because the legal basis for a Ruan-style argument was “reasonably available” when he pleaded guilty and failed to appeal.

The court emphasized two central points:

• The “novelty” standard for cause is demanding; “futility” in a particular circuit (i.e., that controlling circuit precedent would have rejected the claim) does not constitute cause.
• Rehaif v. United States (decided months before Dr. Dimkpa’s plea and sentencing) supplied the “essential legal tools”—especially the presumption of scienter and the application of mens rea to non-adjacent statutory clauses—making a Ruan-type mens rea theory reasonably available in 2019.

Dr. Dimkpa did not challenge the district court’s rejection of “actual innocence” on appeal, so the Fourth Circuit addressed only “cause” and affirmed.

III. Analysis

A. Precedents Cited (and How They Shaped the Holding)

1) The substantive mens rea shift: Ruan v. United States

Ruan v. United States, 597 U.S. 450 (2022), is the substantive trigger for the litigation. It held that § 841’s “knowingly or intentionally” mens rea applies to the “except as authorized” clause, requiring proof beyond a reasonable doubt that the doctor knew or intended that the prescription was unauthorized. The Fourth Circuit treated Ruan as a significant change in circuit law, consistent with its earlier recognition in United States v. Kim, 71 F.4th 155, 160 (4th Cir. 2023), that Ruan “changed the law in this circuit.”

2) Procedural default framework: Bousley v. United States

Bousley v. United States, 523 U.S. 614 (1998), supplied the controlling collateral-review rule: claims not raised on direct review are defaulted and may be raised in habeas only upon showing (1) cause and prejudice or (2) actual innocence. Critically, Bousley also rejects “futility” as cause and refocuses the “novelty” inquiry on whether a claim’s legal basis was “reasonably available,” noting that if the “Federal Reporters were replete” with similar challenges, the claim is not novel. That aspect of Bousley is central to the Fourth Circuit’s reasoning.

3) The “novelty” lens: Reed v. Ross (and its limits)

Reed v. Ross, 468 U.S. 1 (1984), identified three situations where novelty might constitute cause: (i) the Supreme Court overrules its own precedent; (ii) it overturns a widespread, near-unanimous lower-court practice on which it had not spoken; or (iii) it disapproves a practice it arguably had sanctioned.

The Fourth Circuit accepted Reed as a helpful framework but held it is not dispositive after later Supreme Court guidance—particularly Bousley—which directs courts to the bottom-line “reasonable availability” inquiry rather than categorizing the case within Reed. In effect, even if Ruan fits Reed’s “near-unanimous lower-court practice” description, that does not automatically establish cause.

4) “Futility” is not cause: Whiteside v. United States and related authority

The district court relied on Whiteside v. United States, 775 F.3d 180, 185 (4th Cir. 2014) (en banc), to underscore that “futility” in a particular court at a particular time is not “cause.” The Fourth Circuit reinforced this principle using Bousley’s statement that a claim is not excused merely because it was “unacceptable” under then-prevailing precedent.

5) “Available” even if unsettled: Smith v. Murray and United States v. Gaylor

Smith v. Murray, 477 U.S. 527, 537 (1986), and United States v. Gaylor, 828 F.2d 253, 256–57 (4th Cir. 1987), support the proposition that the relevant question is not whether later developments made counsel’s task easier, but whether the claim was available at all; legal “flux” and “unsettled” doctrine do not themselves show unavailability.

6) “Essential legal tools” and the role of other litigants: Engle v. Isaac, United States v. Sanders, Turner v. Jabe, Poyner v. Murray

The Fourth Circuit drew on:

• Engle v. Isaac, 456 U.S. 107, 131–34 (1982), for the idea that a claim is reasonably available when existing doctrine provides the “tools to construct” it—and that the fact others “perceived and litigated” similar claims is strong evidence against novelty.
• United States v. Sanders, 247 F.3d 139, 144–46 (4th Cir. 2001), which read Bousley to mean that even a landscape-changing Supreme Court decision (there, Bailey v. United States, 516 U.S. 137 (1995)) does not create “cause” if similar claims were being raised earlier and prior precedent laid the groundwork. Sanders also illustrates the “essential legal tools” concept and, by analogy, treats later watershed holdings (it discusses the lead-up to Apprendi v. New Jersey, 530 U.S. 466 (2000)) as often foreshadowed enough to be available to diligent counsel.
• Turner v. Jabe, 58 F.3d 924, 929 (4th Cir. 1995), and Poyner v. Murray, 964 F.2d 1404, 1424 (4th Cir. 1992), to emphasize the high bar for novelty and the availability of claims when counsel possesses the “case law necessary to conceive and argue” them.

7) The linchpin for “reasonable availability”: Rehaif v. United States

The decisive move in the opinion is its treatment of Rehaif v. United States, 588 U.S. 225 (2019), as providing the doctrinal template and “essential legal tools” for a Ruan-style argument. Rehaif applied the presumption of scienter to hold that in a “knowing” prosecution, the government must prove not only the act (firearm possession) but also the defendant’s knowledge of the status element (belonging to a prohibited class). The Fourth Circuit viewed Ruan as later employing the same core reasoning and repeatedly citing Rehaif, including for how scienter can apply to clauses not immediately following the mens rea term.

Therefore, although Fourth Circuit precedent at the time (notably United States v. Hurwitz) took an objective view of physician authorization, Rehaif—decided before Dr. Dimkpa’s plea and sentencing—made the argument legally thinkable, constructible, and litigable.

8) Prior circuit precedent on § 841 authorization: United States v. Hurwitz, and post-Ruan recognition of futility: United States v. Smithers

United States v. Hurwitz, 459 F.3d 463, 477–80 (4th Cir. 2006), reflected the pre-Ruan Fourth Circuit approach, rejecting a subjective “good faith” standard and endorsing an objective inquiry.

The court cited United States v. Smithers, 92 F.4th 237, 247 (4th Cir. 2024), which observed that it “would have been futile” to argue for a subjective standard in the Fourth Circuit before Ruan. But Smithers also fits the Fourth Circuit’s broader point: futility does not equate to unavailability for procedural-default “cause.”

9) Non-unanimity in other circuits: United States v. Chube II and United States v. Feingold

The opinion noted that the pre-Ruan consensus was not total: United States v. Chube II, 538 F.3d 693, 698 (7th Cir. 2008), and United States v. Feingold, 454 F.3d 1001, 1008 (9th Cir. 2006), required proof that a doctor intended to act unauthorized. That mattered because it undercut any claim that the objective approach was so entrenched that a subjective scienter argument was beyond reasonable contemplation.

10) Rejecting “foreclosure” by Supreme Court precedent: United States v. Moore, contrasted with United States v. McKinney (and Johnson v. United States)

Dr. Dimkpa argued that United States v. Moore, 423 U.S. 122 (1975), effectively endorsed the objective standard and thus made his claim unavailable. The Fourth Circuit rejected that argument because Ruan itself held that Moore did not address the mens rea question and did not “effectively endorse” an objective scienter standard; Ruan distinguished, not overruled, Moore.

The court contrasted this case with United States v. McKinney, 60 F.4th 188, 193–95 (4th Cir. 2023), where the claim was deemed unavailable because pre-2015 Supreme Court precedent had “effectively foreclosed” vagueness challenges to residual clauses—until Johnson v. United States, 576 U.S. 591 (2015), changed the landscape. In the Fourth Circuit’s view, this case lacked the key feature present in McKinney: binding Supreme Court precedent affirmatively upholding the very practice later invalidated.

11) Statutory-interpretation signals and “carefully crafted” holdings: United States v. Brown

Citing United States v. Brown, 868 F.3d 297, 302 (4th Cir. 2017), the court explained that Rehaif was not a narrow, context-bound decision that carefully avoided broader implications. To the contrary, Rehaif was expressly rooted in general principles of scienter and culpability—making it a stronger building block for analogous arguments under § 841.

B. Legal Reasoning

The court’s reasoning proceeds in three steps:

1. Default is undisputed: Dr. Dimkpa did not raise the mens rea issue in the district court proceedings or on direct appeal. Under Bousley v. United States, that omission triggers procedural default.
2. Novelty is narrow; futility and unsettled law are insufficient: Even though United States v. Hurwitz made a subjective scienter theory nonviable in the Fourth Circuit, “futility” does not amount to “cause.” Nor does doctrinal uncertainty; the question is whether the claim was available to be made.
3. Rehaif made the claim reasonably available: The Fourth Circuit treated Rehaif v. United States as a near-direct doctrinal precursor to Ruan. Both decisions are framed as applications of the presumption of scienter, both address how a mens rea term reaches beyond the immediately adjacent clause, and both stress scienter’s role in separating innocent from wrongful conduct. Because Rehaif was decided before Dr. Dimkpa’s plea and sentencing, counsel had “essential legal tools” to construct and raise the argument.

The court bolstered the “availability” conclusion by noting that other defendants were in fact raising similar claims before Ruan, which Engle v. Isaac and Bousley treat as powerful evidence against novelty.

C. Impact

The decision’s practical effect is to narrow the set of post-Ruan § 2255 petitioners who can obtain relief from pre-Ruan guilty pleas in the Fourth Circuit:

• Many Ruan-based plea-colloquy challenges will be procedurally barred if the defendant did not raise (or preserve) the mens rea issue on direct review, unless another form of “cause” can be shown.
• Rehaif will function as a “reasonable availability” benchmark for scienter-expansion arguments: once Rehaif exists, defendants face a harder task arguing that analogous mens rea theories were unknowable or unavailable.
• Actual innocence becomes comparatively more important for collateral relief. Because Dr. Dimkpa did not pursue that argument on appeal, the opinion signals that, absent cause, many petitioners will have to meet the stringent Bousley “more likely than not that no reasonable juror would have convicted” standard.
• Litigation incentives shift to early preservation: defendants (and counsel) are further encouraged to raise mens rea/statutory-interpretation issues at plea, sentencing, or on direct appeal—even against unfavorable circuit precedent—to avoid later procedural bars.

IV. Complex Concepts Simplified

• § 2255 motion: A federal prisoner’s post-conviction procedure to seek relief (e.g., vacatur) on constitutional or legal grounds. It is not a substitute for a direct appeal.
• Procedural default: If a defendant could have raised a claim on direct appeal but did not, a habeas court generally will not consider it unless an exception applies.
• Cause and prejudice: A gateway to excuse default. “Cause” asks why the claim was not raised earlier (e.g., truly unavailable legal basis). “Prejudice” asks whether the error mattered to the outcome.
• Actual innocence (in this context): Not just legal insufficiency; it requires showing that, in light of all evidence, no reasonable juror would convict.
• Scienter / mens rea: The mental-state element of a crime (e.g., “knowingly,” “intentionally”). The “presumption of scienter” is an interpretive rule that Congress is presumed to require a culpable mental state for criminal liability unless it clearly indicates otherwise.
• Objective vs. subjective authorization (pre- and post-Ruan): Pre-Ruan Fourth Circuit doctrine (as in United States v. Hurwitz) permitted conviction based largely on whether prescriptions were objectively outside professional practice. Post-Ruan, the government must also prove the doctor’s subjective knowledge or intent regarding that lack of authorization.
• “Reasonably available” claim: A claim can be “available” even if it would likely lose under then-existing circuit precedent, so long as the legal building blocks existed to articulate it (and especially if other litigants were doing so).

V. Conclusion

United States v. Okechukwu Dimkpa cements a key Fourth Circuit procedural rule in the wake of Ruan v. United States: a defendant who failed to raise a Ruan-type § 841 mens rea claim on direct review generally cannot show “cause” merely because circuit precedent was adverse, particularly after Rehaif v. United States supplied a broadly framed scienter rationale capable of supporting the argument. The opinion’s significance lies less in redefining § 841 after Ruan than in defining who may invoke Ruan on collateral review—and in reinforcing that preservation, not hindsight, is often decisive in post-conviction litigation.