Fed. R. Evid. 601 — Competency to Testify in General
Plain English
Everyone is presumed competent to testify unless the rules say otherwise—a deliberately low bar that leaves credibility to cross-examination and the jury. In civil cases resting on state-law claims, state competency law applies.
From the Courtroom
Competency is rarely a barrier in federal court; an attack on a witness goes to weight, not admissibility. The exception that matters is the state-law carve-out: in a diversity case under Florida law, Florida’s competency rules apply—so a state Dead Man’s-type issue can resurface even in federal court.
Key Points & Authority
- Presumption of competency for every witness unless a rule provides otherwise.
- State-law civil claims. State competency law governs where state law supplies the rule of decision.
- Weight, not admissibility. Most competency challenges go to credibility for the jury.
Florida Parallel
Florida Parallel: Fed. R. Evid. 601 corresponds to § 90.601, Fla. Stat. (General rule of competency). Both presume every person competent to testify unless a rule provides otherwise. Cross-reference is text-only for now; live links added in a later interlinking pass.
About this rule walkthrough
Part of The Evidence Code, hosted by John M. Phillips — Board Certified Civil Trial Lawyer, Court TV analyst, admitted in 8 states + 9 federal districts + SCOTUS.
Free consultation: (904) 444-4444 · About John Phillips
Educational only — not legal advice.
Rule Text (verbatim from the Florida Supreme Court)
Every person is competent to be a witness unless these rules provide otherwise. But in a civil case, state law governs the witness’s competency regarding a claim or defense for which state law supplies the rule of decision.
Educational reference. Educational summary of the Federal Rules of Evidence, not legal advice.
What this rule means in plain English
Everyone is presumed competent to testify unless the rules say otherwise—a deliberately low bar that leaves credibility to cross-examination and the jury. In civil cases resting on state-law claims, state competency law applies.