Competency to Testify in General
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.
(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1934; Apr. 26, 2011, eff. Dec. 1, 2011.)
Notes of Advisory Committee on Proposed Rules
This general ground-clearing eliminates all grounds of incompetency not specifically recognized in the succeeding rules of this Article. Included among the grounds thus abolished are religious belief, conviction of crime, and connection with the litigation as a party or interested person or spouse of a party or interested person. With the exception of the so-called Dead Man's Acts, American jurisdictions generally have ceased to recognize these grounds.
The Dead Man's Acts are surviving traces of the common law disqualification of parties and interested persons. They exist in variety too great to convey conviction of their wisdom and effectiveness. These rules contain no provision of this kind. For the reasoning underlying the decision not to give effect to state statutes in diversity cases, see the Advisory Committee's Note to Rule 501.
No mental or moral qualifications for testifying as a witness are specified. Standards of mental capacity have proved elusive in actual application. A leading commentator observes that few witnesses are disqualified on that ground. Weihofen, Testimonial Competence and Credibility, 34 Geo. Wash.L.Rev. 53 (1965). Discretion is regularly exercised in favor of allowing the testimony. A witness wholly without capacity is difficult to imagine. The question is one particularly suited to the jury as one of weight and credibility, subject to judicial authority to review the sufficiency of the evidence. 2 Wigmore §§501, 509. Standards of moral qualification in practice consist essentially of evaluating a person's truthfulness in terms of his own answers about it. Their principal utility is in affording an opportunity on voir dire examination to impress upon the witness his moral duty. This result may, however, be accomplished more directly, and without haggling in terms of legal standards, by the manner of administering the oath or affirmation under Rule 603.
Admissibility of religious belief as a ground of impeachment is treated in Rule 610. Conviction of crime as a ground of impeachment is the subject of Rule 609. Marital relationship is the basis for privilege under Rule 505. Interest in the outcome of litigation and mental capacity are, of course, highly relevant to credibility and require no special treatment to render them admissible along with other matters bearing upon the perception, memory, and narration of witnesses.
Notes of Committee on the Judiciary, House Report No. 93–650
Rule 601 as submitted to the Congress provided that “Every person is competent to be a witness except as otherwise provided in these rules.” One effect of the Rule as proposed would have been to abolish age, mental capacity, and other grounds recognized in some State jurisdictions as making a person incompetent as a witness. The greatest controversy centered around the Rule's rendering inapplicable in the federal courts the so-called Dead Man's Statutes which exist in some States. Acknowledging that there is substantial disagreement as to the merit of Dead Man's Statutes, the Committee nevertheless believed that where such statutes have been enacted they represent State policy which should not be overturned in the absence of a compelling federal interest. The Committee therefore amended the Rule to make competency in civil actions determinable in accordance with State law with respect to elements of claims or defenses as to which State law supplies the rule of decision. Cf. Courtland v. Walston & Co., Inc., 340 F.Supp. 1076, 1087–1092 (S.D.N.Y. 1972).
Notes of Committee on the Judiciary, Senate Report No. 93–1277
The amendment to rule 601 parallels the treatment accorded rule 501 discussed immediately above.
Notes of Conference Committee, House Report No. 93–1597
Rule 601 deals with competency of witnesses. Both the House and Senate bills provide that federal competency law applies in criminal cases. In civil actions and proceedings, the House bill provides that state competency law applies “to an element of a claim or defense as to which State law supplies the rule of decision.” The Senate bill provides that “in civil actions and proceedings arising under 28 U.S.C. §1332 or 28 U.S.C. §1335, or between citizens of different States and removed under 28 U.S.C. §1441(b) the competency of a witness, person, government, State or political subdivision thereof is determined in accordance with State law, unless with respect to the particular claim or defense, Federal law supplies the rule of decision.”
The wording of the House and Senate bills differs in the treatment of civil actions and proceedings. The rule in the House bill applies to evidence that relates to “an element of a claim or defense.” If an item of proof tends to support or defeat a claim or defense, or an element of a claim or defense, and if state law supplies the rule of decision for that claim or defense, then state competency law applies to that item of proof.
For reasons similar to those underlying its action on Rule 501, the Conference adopts the House provision.
Committee Notes on Rules—2011 Amendment
The language of Rule 601 has been amended as part of the restyling of the Evidence Rules to make them more easily understood and to make style and terminology consistent throughout the rules. These changes are intended to be stylistic only. There is no intent to change any result in any ruling on evidence admissibility.