ADA Title I Requires But-For Causation; USERRA §4311 Does Not Reach Disability-Based Bias: The Tenth Circuit’s Published Clarification in Sellman v. Aviation Training Consulting

Introduction

In a published decision, the United States Court of Appeals for the Tenth Circuit affirmed summary judgment for Aviation Training Consulting, LLC (ATC) against former employee Nicholas Sellman, a Marine veteran and VA-rated disabled veteran. The opinion addresses two pivotal areas:

It formally clarifies that ADA Title I employment discrimination claims, like ADA retaliation claims, require proof of but-for causation in the Tenth Circuit.
It confirms that USERRA’s anti-discrimination and anti-retaliation provisions (§ 4311) protect against bias “because of” military service, but do not reach discrimination “because of” a veteran’s disability status—even if the disability arose from military service.

The case arises from ATC’s decision not to renew Sellman’s one-year contract as a Loadmaster Instructor on a KC-130 training program in Kuwait. After his supervisor, Director of Operations Richard Sofge (himself a disabled veteran), made disparaging remarks about Sellman’s VA disability rating, Sellman complained to ATC’s HR department. HR investigated, and a company vice president (also a disabled veteran) reprimanded Sofge. Subsequently, the FAA questioned renewal of Sellman’s flight medical certificate; it briefly expired before being renewed days later. Around the same time, Sellman received a negative performance appraisal from Chief Pilot Graham Mueller and had prior performance concerns documented by Vice President Michael Young.

Sellman alleged ATC declined to renew his contract because of disability discrimination and in retaliation for his HR complaint, in violation of the ADA, and because of his status as a disabled veteran and in retaliation for complaining about such discrimination, in violation of USERRA. The district court granted summary judgment to ATC, and the Tenth Circuit affirmed.

Summary of the Opinion

ADA discrimination and retaliation (indirect evidence; McDonnell Douglas): The court assumed, without deciding, that Sellman established prima facie cases and held ATC articulated a legitimate, non-discriminatory, non-retaliatory reason—subpar performance. At step three, Sellman failed to create a triable issue that ATC’s reason was pretext, including under the cat’s paw theory. The decision-makers relied on Mueller’s negative review, Young’s independent assessment of earlier performance concerns, and the lapse of the FAA certificate. No evidence showed discriminatory or retaliatory animus by the decision-makers or an unbroken causal chain from a biased subordinate.
But-for causation under the ADA: The panel explicitly holds that ADA Title I employment discrimination claims, like ADA retaliation claims, require proof of but-for causation. The court equates earlier “determining factor” language with but-for causation and aligns with other circuits.
USERRA scope: The court holds that § 4311’s anti-discrimination and anti-retaliation protections extend to adverse actions taken “on the basis of” military service, not on the basis of disability status—even if service-related. A separate USERRA reemployment provision addresses disabilities, but § 4311 does not.
Disposition: Affirmed summary judgment for ATC on all claims.

Detailed Analysis

Factual Context and Decision Path

Key facts, viewed favorably to Sellman, include:

Sellman disclosed a VA disability rating (increased from 90% to 100%). His disability bases included PTSD, degenerative back disease, and a sleep disorder.
Director of Operations Sofge made disparaging remarks about Sellman’s VA disability rating. HR investigated, and Vice President Dennis Stephens reprimanded Sofge; no further remarks occurred after counseling.
The FAA required additional information to renew Sellman’s medical certification; it expired at the end of February 2018 and was renewed days later. During this period, ATC experienced uncertainty regarding flight eligibility.
Chief Pilot Mueller conducted a performance appraisal rating Sellman “marginal” in dependability, communication, and initiative, with specific criticisms (e.g., difficulty completing tasks without supervision; deficient communication; reluctance to perform beyond directed duties). Vice President Young had previously told Sellman to “tighten it up.”
Renewal decision: Vice Presidents Young and Stephens decided not to renew based on performance (as reflected in Mueller’s evaluation and Young’s own observations), and CEO Cox approved. Cox did not know about Sellman’s HR complaint or the reasons for the FAA lapse; Young did not know of the disability or complaint; Stephens knew of the VA rating and complaint because he personally reprimanded Sofge.

Against this record, the panel affirmed summary judgment, finding no genuine dispute that performance—not disability or retaliation—drove the non-renewal, and that the cat’s paw theory failed on causation and reliance elements.

Precedents Cited and Their Influence

McDonnell Douglas Corp. v. Green, 411 U.S. 792 (1973); Tex. Dep’t of Cmty. Affairs v. Burdine, 450 U.S. 248 (1981): Provide the burden-shifting framework for indirect evidence discrimination and retaliation claims. Here, the court assumed prima facie showings and found ATC’s legitimate reason (subpar performance) unrebutted by evidence of pretext.
Edmonds-Radford v. Southwest Airlines, 17 F.4th 975 (10th Cir. 2021): Reinforces that the pretext inquiry assesses facts as they appeared to the decisionmakers; courts do not second-guess business judgment if honestly held. The panel leaned on this to reject Sellman’s disagreement with his performance assessment absent evidence of insincerity.
Iweha v. Kansas, 121 F.4th 1208 (10th Cir. 2024), and EEOC v. BCI Coca-Cola Bottling Co., 450 F.3d 476 (10th Cir. 2006): Outline the cat’s paw doctrine. Liability requires an unbroken causal chain from a biased subordinate to the unbiased decisionmaker, and “uncritical reliance” on biased input. Independent verification breaks the chain. The panel found multiple independent bases (Mueller’s evaluation, Young’s own observations, FAA lapse) defeated cat’s paw.
Singh v. Cordle, 936 F.3d 1022 (10th Cir. 2019), and Staub v. Proctor Hospital, 562 U.S. 411 (2011): Establish elements of subordinate bias liability and intent-to-cause requirement. The court accepted arguably sufficient evidence of Sofge’s animus but found no causal conduit to the decisionmakers’ choice, particularly given temporal sequence and intervening assessments.
Lincoln v. BNSF Ry. Co., 900 F.3d 1166 (10th Cir. 2018): Holds ADA retaliation requires but-for causation. The Sellman panel extends the but-for requirement expressly to ADA Title I discrimination claims as well, harmonizing standards.
Hampton v. Utah Dept. of Corrections, 87 F.4th 1183 (10th Cir. 2023): Used “determining factor” phrasing in applying ADA principles to a Rehabilitation Act case. Sellman resolves any ambiguity by equating “determining factor” with but-for causation in ADA employment cases.
Cline v. Clinical Perfusion Systems, Inc., 94 F.4th 926 (10th Cir. 2024): Though a state-law age case, it reflects the court’s comfort with “but-for” as synonymous with “determining factor,” supporting Sellman’s equivalence.
Kincaid v. Unified School Dist. No. 500, 94 F.4th 936 (10th Cir. 2024): Reiterates the pretext standard—employer’s reasons must be so implausible or inconsistent as to be unworthy of credence. The court found no such weaknesses in ATC’s rationale.
Berry v. T-Mobile USA, Inc., 490 F.3d 1211 (10th Cir. 2007), and Randle v. City of Aurora, 69 F.3d 441 (10th Cir. 1995): Deviation from internal procedures, by itself, does not establish pretext. Applied here to arguments about appraisal signatures and review formalities.
Garrett v. Hewlett-Packard Co., 305 F.3d 1210 (10th Cir. 2002); Debord v. Mercy Health System of Kansas, 737 F.3d 642 (10th Cir. 2013); Riggs v. AirTran Airways, 497 F.3d 1108 (10th Cir. 2007): Courts are skeptical of purely subjective criteria, but subjectivity alone does not prove pretext. The court emphasized Mueller’s specific, concrete performance criticisms.
Christopher v. Adam's Mark Hotels, 137 F.3d 1069 (8th Cir. 1998); Anderson v. AOL, LLC, 363 F. App’x 581 (10th Cir. 2010): Knowledge of disability or protected activity alone is insufficient to show pretext. The panel relied on this to reject inferences based solely on Stephens’s knowledge.
Kelly v. Omaha Public Power Dist., 75 F.4th 877 (8th Cir. 2023) (and 604 F. Supp. 3d 800 (D. Neb. 2022)): USERRA protects against discrimination on the basis of military service; benefits decisions tied to service-related disability are not covered by § 4311. This aligns with Sellman’s holding.
Carroll v. Delaware River Port Authority, 89 F. Supp. 3d 628 (D.N.J. 2015); Ferrell v. Ezpawn Oklahoma, Inc., 2019 WL 3207797 (W.D. Okla. July 16, 2019): District court cases refusing to extend § 4311 to disability-based discrimination; Sellman adopts this reading at the circuit level.
Starr v. QuikTrip Corp., 655 F. App’x 642 (10th Cir. 2016): Confirms that USERRA’s motivating-factor standard pertains to military service status, underscoring that disability status is analytically distinct for § 4311 purposes.
Persuasive out-of-circuit ADA cases on causation: Murray v. Mayo Clinic, 934 F.3d 1101 (9th Cir. 2019); Natofsky v. City of New York, 921 F.3d 337 (2d Cir. 2019) (joining the Fourth, Sixth, and Seventh Circuits). Sellman aligns the Tenth Circuit with these authorities.

Legal Reasoning

The court’s analysis proceeds in three key moves.

Pretext analysis under McDonnell Douglas: ATC’s proffered reason (subpar performance) was supported by:
- Mueller’s contemporaneous, specific performance appraisal citing concrete deficiencies;
- Young’s earlier, independent observation that Sellman lagged peers and needed to “tighten it up”;
- The lapse of the FAA medical certificate—a job requirement—before renewal.
The court emphasized it does not second-guess business judgment where the employer honestly believes its stated reasons. No evidence suggested the decisionmakers disbelieved their rationale or acted with discriminatory or retaliatory motive.
Cat’s paw theory fails for lack of an unbroken causal chain and uncritical reliance:
- Although Sofge’s remarks permitted an inference of bias, the decisionmakers did not “uncritically rely” on him; they relied on Mueller’s appraisal, Young’s own knowledge, and the FAA lapse. This independent verification breaks the causal chain.
- There was no evidence that Sofge tainted Mueller’s appraisal or that Mueller knew of the disability rating or the HR complaint (key to retaliation). The only “cooling” of demeanor was insufficient to infer knowledge or animus.
- Temporal sequence matters: Sofge’s single “I do not want to renew” email came after Mueller’s detailed negative appraisal and months after Young’s earlier performance warning—and Sofge acknowledged the decision was not his call.
Under Iweha and BCI Coca-Cola, these facts defeat subordinate-bias liability.
Clarified causation standard and statutory scope:
- ADA Title I causation: Building on Lincoln (retaliation) and harmonizing with Hampton, the court expressly holds that ADA employment discrimination claims require but-for causation, equating “determining factor” with but-for causation in this context. This aligns the Tenth Circuit with the Second, Fourth, Sixth, Seventh, and Ninth Circuits.
- USERRA § 4311 scope: The statute prohibits discrimination “on the basis of” military service (membership, application, performance, or obligation), not on the basis of disability status. Other USERRA provisions (e.g., § 4313 reemployment obligations) expressly address disabled servicemembers, but § 4311 does not. Thus, disability-based discrimination and retaliation claims fall outside § 4311, even when the disability is service-connected.

Impact and Implications

1) ADA litigation in the Tenth Circuit

Higher causation threshold: Plaintiffs now must prove but-for causation for ADA Title I discrimination as well as retaliation. Mixed-motive (motivating-factor) theories do not apply under the ADA in this circuit.
Cat’s paw narrowed by independent review: Employers can defeat subordinate-bias claims by ensuring decisionmakers rely on independent assessments and do not simply adopt a biased supervisor’s view.
Evidence focus: Plaintiffs will need concrete proof that the subordinate intended to cause the adverse action and that their act was the but-for cause of the decision—speculation about who “must have known” is inadequate.

2) USERRA claims by disabled veterans

Statutory limits clarified: Disability-based discrimination and retaliation claims are not actionable under § 4311. Veterans alleging disability discrimination should proceed under the ADA or Rehabilitation Act, not USERRA.
Reemployment vs. anti-discrimination provisions: While USERRA contains reemployment accommodations for disabled servicemembers (§ 4313), its anti-discrimination clause remains tethered to military service, not disability.

3) Employer compliance and risk management

Independent decisionmaking: Use multi-source, documented performance evidence (e.g., detailed appraisals, prior counseling, objective qualifications like required certifications) to insulate decisions from subordinate bias.
HR intervention matters: Prompt investigation and corrective action (as with Sofge’s reprimand) both remedy workplace issues and provide contemporaneous evidence against retaliatory motives.
Process deviations are not dispositive: Minor procedural irregularities (e.g., missing signatures) seldom show pretext absent evidence of animus or dishonesty and where the core reasons are well-documented.

4) Employee-side strategy

Build the causal chain: For cat’s paw, develop proof that the biased subordinate supplied decisive facts and the decisionmaker relied on them without independent verification; show the subordinate’s act was outcome-determinative.
Target knowledge and intent: Identify direct or circumstantial evidence that decisionmakers (or the appraising supervisor) knew of disability or protected activity and acted with animus or retaliatory intent.
Choose statutes strategically: For disabled veterans, frame claims under the ADA/RA rather than USERRA § 4311, unless the adverse action was motivated by military service itself.

Complex Concepts Simplified

But-for causation: The adverse action would not have occurred in the absence of the protected trait or activity. There can be multiple but-for causes, but the protected factor must be outcome-determinative.
McDonnell Douglas framework: A three-step burden-shifting model for circumstantial evidence cases: (1) prima facie case; (2) employer’s legitimate, non-discriminatory reason; (3) plaintiff’s proof of pretext (that the stated reason is not the real reason).
Pretext: Showing the employer’s reason is so weak, implausible, inconsistent, or contradictory that a jury could find it unworthy of belief and infer discrimination or retaliation.
Cat’s paw (biased subordinate) theory: Allows liability when a biased non-decisionmaker manipulates an unbiased decisionmaker into acting adversely. Requires an unbroken causal chain, intent to cause the action, and decisionmaker reliance on the biased input without independent verification.
Business judgment rule (in this context): Courts do not reassess whether the employer’s decision was wise or correct—only whether the employer honestly believed its stated reasons and did not act for unlawful reasons.
USERRA § 4311 vs. § 4313: Section 4311 prohibits discrimination “on the basis of” military service and retaliation for asserting USERRA rights. Section 4313 addresses reemployment rights and accommodations for disabled servicemembers; it does not expand § 4311 to cover disability-based discrimination.
FAA medical certificate (aviation context): Required for flight eligibility. Its lapse can constitute a legitimate, job-related ground relevant to performance and renewal decisions for flight crew roles.

Conclusion

Sellman is a consequential, published decision that does three things. First, it cements in the Tenth Circuit that ADA Title I employment discrimination claims—like ADA retaliation claims—require but-for causation. Second, it underscores the rigor of the cat’s paw theory in ADA cases: plaintiffs must prove an unbroken chain from a biased subordinate’s intentional act to the adverse decision, without independent verification by unbiased decisionmakers. Third, it clarifies USERRA’s limits: § 4311 does not cover disability-based discrimination or retaliation, even for disabilities arising from military service.

For employers, the case highlights the value of independent, specific performance assessments and the importance of avoiding uncritical reliance on any one supervisor, particularly where bias is alleged. For employees—especially disabled veterans—the opinion signals that ADA and Rehabilitation Act frameworks are the appropriate vehicles for disability-based claims, while USERRA § 4311 remains focused on discrimination tied to military service itself. Overall, Sellman provides a clear, structured roadmap for courts and practitioners on causation, pretext, and the scope of protection across these statutes.