Nassar: Why Title VII Retaliation Now Requires But-For Causation

You filed an EEOC charge alleging race discrimination. Three weeks later, your supervisor reassigned your best accounts to a colleague who didn't complain.

The timing looks suspicious. But proving your complaint caused the reassignment just got harder.

In 2013, the Supreme Court redrew the causation line for Title VII retaliation claims in University of Texas Southwestern Medical Center v. Nassar, 570 U.S. 338 (2013). The Court held that retaliation plaintiffs must prove but-for causation—that the adverse action would not have occurred but for the protected activity—rather than the easier "motivating factor" test that applies to status-based discrimination claims.

Here's what you'll learn:

• Why Nassar split retaliation claims from discrimination claims on causation
• What but-for causation means in practice—and how it differs from motivating-factor
• How the heightened standard affects what evidence you need to survive summary judgment

The Nassar Decision: Two Statutes, Two Standards

Dr. Naiel Nassar, a physician of Middle Eastern descent, worked at the University of Texas Southwestern Medical Center. He complained that his supervisor harassed him based on religion and national origin.

When Dr. Nassar tried to resign from the Medical Center but continue working at the affiliated hospital, his supervisor intervened. The hospital withdrew its job offer.

Dr. Nassar sued under Title VII, alleging both discrimination and retaliation.

The case turned on a statutory interpretation question: Does the same causation standard apply to both types of claims?

Section 2000e-2(m): The Motivating-Factor Standard

Title VII's discrimination provision, codified at 42 U.S.C. §2000e-2(m), says an unlawful employment practice is established when "race, color, religion, sex, or national origin was a motivating factor for any employment practice, even though other factors also motivated the practice."

Under this standard, you don't have to prove your protected characteristic was the only reason—or even the main reason—for the adverse action. You just have to show it played some role.

That's a plaintiff-friendly standard.

Section 2000e-3(a): The Retaliation Provision

Title VII's retaliation clause, §2000e-3(a), uses different language. It makes it unlawful to discriminate against an employee "because such individual has opposed any practice made an unlawful employment practice" or participated in a Title VII proceeding.

The word is "because"—not "motivating factor."

In Nassar, the Supreme Court held that textual difference matters. A lot.

What But-For Causation Actually Means

But-for causation asks a counterfactual question: Would the employer have taken the same action even if you had not engaged in protected activity?

If the answer is "yes," your retaliation claim fails—even if your complaint played some role in the decision.

Here's where it gets interesting:

Under the old motivating-factor test, you could win by showing retaliation was one of several reasons for the adverse action. Mixed-motive cases were viable.

Under but-for causation, mixed motives don't cut it. Your protected activity must be the determinative cause—the reason the action happened.

A Concrete Example

Imagine two employees miss the same performance target in Q3. Employee A gets a written warning. Employee B—who filed an EEOC charge two months earlier—gets terminated.

Under motivating-factor, you'd ask: Did the EEOC charge play any role in the termination decision?

Under but-for causation, you ask: Would Employee B have been terminated anyway, even without the EEOC charge?

If the employer has documentation showing it fires every employee who misses that target twice in a year—and Employee B had a prior Q1 miss—the but-for answer might be "yes, termination would have occurred regardless."

Your claim fails, even if the manager also disliked Employee B for complaining.

How Nassar Changed the Evidentiary Landscape

The Nassar standard didn't just shift the legal test. It changed what evidence matters at summary judgment.

Temporal Proximity Still Matters—But It's Not Enough

Before Nassar, close timing between protected activity and an adverse action could carry a retaliation claim to trial. Courts recognized that "very close" temporal proximity—measured in days or weeks—supports an inference of retaliatory intent.

The Fifth Circuit in Nassar had allowed the case to proceed partly on that theory. Dr. Nassar's complaints preceded the withdrawal of his job offer by a matter of months.

The Supreme Court didn't eliminate temporal proximity as evidence. But it clarified that proximity alone doesn't satisfy but-for causation when the employer offers a competing explanation.

You still benefit from suspicious timing. You can still invoke the framework from Burlington v. White: The Materially-Adverse Standard, Explained, which defines what counts as an adverse action in retaliation cases.

But now you also need evidence that rebuts the employer's alternative explanation—something showing the proffered reason is pretextual or that retaliation was the determinative cause.

Comparative Evidence Becomes Critical

Post-Nassar, plaintiffs increasingly rely on comparative evidence: How did the employer treat similarly situated employees who didn't engage in protected activity?

If your manager tolerated the same performance miss in three colleagues who never filed complaints, that disparity supports but-for causation. It suggests you would not have been terminated absent your EEOC charge.

If everyone who missed the target got fired—protected activity or not—your retaliation claim weakens under the but-for test.

But-For Causation Beyond Title VII

The Nassar rule is specific to Title VII retaliation claims. But its reasoning has rippled outward.

Courts have applied but-for causation to §1981 retaliation claims, relying on similar statutory text. (The Supreme Court later confirmed this approach in Comcast v. NAAAOM: But-For Causation Under §1981.)

Some federal circuits have extended Nassar's logic to retaliation claims under other statutes with "because" language—though results vary by circuit and statute.

Here's the thing:

Not every retaliation statute uses "because." Some explicitly incorporate a motivating-factor or contributing-factor standard. The Whistleblower Protection Act, certain environmental-protection statutes, and some state laws set a lower causation bar than Nassar.

Always check the specific statute you're proceeding under.

What Nassar Means for Dual-Motive Cases

Employers rarely admit retaliatory intent. They offer legitimate, non-retaliatory reasons: poor performance, restructuring, attendance issues.

Sometimes those reasons are real. Sometimes they're pretextual. Often the truth sits somewhere in between—management did have concerns about performance, and the employee's complaint accelerated a termination decision that might have come later or not at all.

That's a dual-motive scenario.

Under motivating-factor causation, dual motives favor plaintiffs. You win if retaliation played any role.

Under but-for causation, dual motives create a factual puzzle: Which motive was determinative?

Now, here's where it gets interesting:

Even under Nassar, pretext evidence still works. If you can show the employer's stated reason is false—fabricated after the fact, inconsistently applied, or contradicted by the decision-maker's own emails—a jury can infer the real but-for cause was retaliation.

The standard is higher. The path is narrower. But it's not impossible.

How Nassar Affects Settlement Dynamics

The causation standard doesn't just shape trial outcomes. It shapes whether you reach trial at all.

Defense counsel know that Nassar gives them a stronger summary-judgment motion. If they can point to a documented, pre-complaint performance issue—even a minor one—they'll argue you can't prove but-for causation.

That shifts settlement leverage.

Pre-Nassar, employers facing strong temporal proximity often settled rather than risk a jury trial. Post-Nassar, more defendants push for summary judgment, betting the court will find the alternative explanation sufficient to defeat causation.

The data bears this out: Summary judgment is granted more frequently in Title VII retaliation cases post-2013 than in the preceding decade—though plaintiffs with strong comparator evidence and pretext documentation still survive.

Practical Implications for Evidence Preservation

Because but-for causation focuses on what would have happened in the counterfactual world without your complaint, the best evidence is often comparative and temporal.

You want documentation showing:

• How similarly situated employees were treated for the same alleged infractions
• Whether the employer's stated reason was documented before your protected activity
• Whether decision-makers' explanations shifted over time
• Whether the adverse action followed a different process than usual

Performance reviews, emails, policy manuals, and prior disciplinary records become critical. If your employer never fired someone for a single attendance miss before, that pattern supports your but-for argument.

If three employees missed the same deadline last quarter and received coaching rather than termination, that disparity matters.

The Relationship Between Burlington and Nassar

It's easy to confuse these two cases—they're both retaliation landmarks decided within a decade of each other.

But they address different elements:

Burlington Northern & Santa Fe Railway Co. v. White, 548 U.S. 53 (2006), defined adverse action in retaliation cases. The Court held that Title VII retaliation isn't limited to "ultimate employment decisions" like hiring and firing. Any action that "might well have dissuaded a reasonable worker from making or supporting a charge of discrimination" qualifies.

That's a broad, plaintiff-friendly standard for what counts as retaliation.

Nassar raised the bar on causation—proving the adverse action happened because of the protected activity.

You can have a materially adverse action under Burlington but still lose under Nassar if you can't prove but-for causation.

Both matter. One opens the door; the other determines whether you can walk through it.