Can the Burden of Proof Shift? Presumptions and Defenses

Can the burden of proof shift?

Yes, but usually only part of it. The burden of proof has two parts: the burden of production (putting forward enough evidence to make an issue live) and the burden of persuasion (convincing the fact-finder to the required standard). Presumptions and prima facie cases can move the burden of production, and an affirmative defense can place a burden on the defending party for that defense. The persuasion burden on the main claim usually stays where it started. The rules vary by claim and jurisdiction, so treat this as general education, not legal advice.

The assumption that the party bringing the case carries every burden throughout is close to right for the main claim, and wrong for several issues around it.

What are the two parts of the "burden of proof"?

The phrase covers two different tasks. The burden of production (sometimes called the burden of going forward, or in Commonwealth systems the evidential burden) asks whether a party has offered enough evidence for an issue to be considered at all. The burden of persuasion asks whether, once all the evidence is in, the fact-finder is convinced to the applicable standard, such as a preponderance of the evidence or proof beyond a reasonable doubt.

Most talk of "burden shifting" describes the first task moving while the second stays put. See also burden of proof versus standard of proof and legal burden versus evidential burden, which works through the same split using statutory language from outside the United States.

What does a legal presumption do?

A legal presumption is a rule that, once one fact (the basic fact) is established, another fact (the presumed fact) is taken as established unless the opposing party offers evidence against it.

In federal civil cases, Federal Rule of Evidence 301 states the default: "In a civil case, unless a federal statute or these rules provide otherwise, the party against whom a presumption is directed has the burden of producing evidence to rebut the presumption. But this rule does not shift the burden of persuasion, which remains on the party who had it originally."

What moves is the duty to produce rebuttal evidence, not the duty to win the issue, and the rule opens with an exception: a statute can set a different allocation. State courts follow their own evidence codes, and jurisdictions differ on how much force a presumption keeps once rebuttal evidence arrives. Check the rule that governs your forum.

What is a prima facie case, and what happens once one is made?

Prima facie is Latin for "at first sight" or "on the face of it", as the Legal Information Institute's definition explains. A prima facie case is a set of basic facts that, if proved, is enough to require a response from the other side.

The best-known American illustration is the burden-shifting framework the US Supreme Court restated in Texas Department of Community Affairs v. Burdine (1981), an employment discrimination case. The Court set out three steps:

1. "First, the plaintiff has the burden of proving by the preponderance of the evidence a prima facie case of discrimination."
2. If the plaintiff succeeds, the burden shifts to the employer "to articulate some legitimate, nondiscriminatory reason for the employee's rejection."
3. If the employer does so, the plaintiff must have an opportunity to prove by a preponderance of the evidence that the employer's stated reasons "were not its true reasons, but were a pretext for discrimination."

The same opinion states that "[t]he ultimate burden of persuading the trier of fact that the defendant intentionally discriminated against the plaintiff remains at all times with the plaintiff," and that "[t]he defendant need not persuade the court that it was actually motivated by the proffered reasons." The employer's step-two burden is to produce a reason, not to prove it. That is burden shifting in its most common form: production moves back and forth, persuasion does not. The framework belongs to particular claims; other claim types use different structures.

Who has the burden of proof on an affirmative defense?

An affirmative defense is, in the words of the Legal Information Institute, "a defense in which the defendant introduces evidence, which, if found to be credible, will negate criminal liability or civil liability, even if it is proven that the defendant committed the alleged acts." It does not dispute the claim; it offers a separate reason the claim should fail.

In federal civil practice, Federal Rule of Civil Procedure 8(c)(1) requires a responding party to "affirmatively state any avoidance or affirmative defense," and its list includes, among others, assumption of risk, estoppel, fraud, release, res judicata, statute of limitations and waiver.

The burden on those defenses typically sits with the party raising them. The Ninth Circuit's model civil jury instruction 1.5, Claims and Defenses, includes the optional sentence "[The defendant has the burden of proof on these [counterclaims and/or affirmative defenses.]]", and instruction 1.6 applies the preponderance standard to "any claim [or affirmative defense]". Model instructions are not binding, and other courts word these points differently.

So a civil defendant need not disprove the claim, but one relying on, say, the statute of limitations generally has to establish the facts that make that defense apply.

Does the same rule apply to criminal affirmative defenses?

Criminal cases add a constitutional floor. The prosecution must prove every element of the offense beyond a reasonable doubt, a principle the Supreme Court traced to In re Winship in Martin v. Ohio (1987). Within that floor, the allocation of defenses varies sharply.

• Self-defense in Ohio, as it stood in 1987. Martin reviewed an Ohio rule under which, as the opinion put it, "Self-defense is an affirmative defense under Ohio law and therefore must be proved by the defendant." The Court concluded: "We agree with the State and its Supreme Court that this conviction did not violate the Due Process Clause." It also noted that "all but two of the States, Ohio and South Carolina, have abandoned the common-law rule". That describes what the Constitution permits, not what any state requires today.
• Self-defense in federal court in the Ninth Circuit. The circuit's model criminal instruction 5.10 (2022 edition, last updated March 2026) tells jurors that "the government must prove beyond a reasonable doubt, with all of you agreeing, that the defendant did not act in reasonable self-defense." Its comment adds that a defendant is entitled to the instruction when "there is any foundation in the evidence, even though the evidence may be weak, insufficient, inconsistent or of doubtful credibility." The defendant's task there is production only; persuasion stays with the prosecution.
• Duress in federal court. In Dixon v. United States (2006), the Court presumed that Congress intended "the petitioner to bear the burden of proving the defense of duress by a preponderance of the evidence."
• Insanity in federal court. Under 18 U.S.C. § 17(b), "The defendant has the burden of proving the defense of insanity by clear and convincing evidence."

The same label can therefore mean a light production burden in one setting and a full persuasion burden at a demanding standard in another. The guide to the three standards of proof explains how those standards differ.

Does the burden of persuasion on the main claim ever move?

Rarely, and only when a specific rule says so. Rule 301 keeps persuasion with "the party who had it originally" unless a statute or rule provides otherwise, and Burdine keeps the ultimate burden with the plaintiff "at all times". When persuasion on an issue sits with the other side, it is usually because a statute put it there from the outset or the issue is a separate affirmative defense.

The practical consequence of a production burden is that a party who fails to meet it can lose the issue before the fact-finder weighs it. The guide to motions to dismiss versus summary judgment describes one stage at which a court asks whether there is enough evidence to go forward.

What should you confirm for a specific case?

Four questions sort out most confusion:

1. Which issue is in play? The main claim, a presumed fact, or a separate defense.
2. Which burden is moving? Production, persuasion, or both.
3. What standard applies to that burden? Preponderance, clear and convincing evidence, or beyond a reasonable doubt.
4. What source allocates it? A statute, a court rule, a pattern jury instruction or case law in the relevant jurisdiction.

The answers differ by claim, court and jurisdiction, and change when statutes are amended. For anything beyond general understanding, including a pending or threatened case, speak to a licensed attorney in the jurisdiction concerned.

Sources

• Federal Rule of Evidence 301, Legal Information Institute
• Federal Rule of Civil Procedure 8, Legal Information Institute
• Prima facie, Wex, Legal Information Institute
• Affirmative defense, Wex, Legal Information Institute
• Texas Department of Community Affairs v. Burdine, 450 U.S. 248 (1981)
• Martin v. Ohio, 480 U.S. 228 (1987)
• Dixon v. United States (2006)
• 18 U.S. Code § 17, Insanity defense
• Ninth Circuit Model Civil Jury Instruction 1.5, Claims and Defenses
• Ninth Circuit Model Civil Jury Instruction 1.6, Burden of Proof—Preponderance of the Evidence
• Ninth Circuit Manual of Model Criminal Jury Instructions (last updated March 2026)