While judges believe the Rules of Evidence are their tools for controlling lawyers, I have always believed and taught that knowledge of the Rules is what permits lawyers to control the courtroom.  This is true in at least two regards.

Because the litigation process is adversarial, it is the lawyer who addresses evidence claims in limine or by objection who decide in most instances whether an evidentiary issue will even be ‘on the table’ for judicial consideration.   “Advocates take an active role, whereas the judge remains a passive participant.”  United States v. Loughner, 672 F.3d 731, 762 (9th Cir. 2012)  And lawyers who know the Rules – know their language, their theoretical underpinnings, their interplay with one another, their interpretation through decisional law and commentary, and their application to specific patterns of facts – set the conversation and dominate it, framing the issues and leading the discussion.

Is there one Rule that is so powerful above all others that it gives control, or the potential for control to the lawyer?  Posing the question “what Rule of Evidence is the most powerful” – itself a question with inherent ambiguity, as “powerful” may have varied meanings – to colleagues is a test I recently conducted, simply to see what responses were generated.  First I’ll report what skilled Evidence scholars, with litigation backgrounds, replied; and then share my own answer, one selected by only one of the respondents.


  • “404(b)”
  • “403 (and its “cousins” in 609 and 703).  This Rule applies to nearly every evidentiary ruling and can even bar presumptively admissible evidence, see 413, etc.”
  • “404B — we all know people just want it for propensity.”
  • “802 and hearsay.”
  • “Relevance – Fed R Evid 402”
  • “I would give different answers depending on whether the case is criminal or civil.  If criminal, then 404(b).  If civil, then 702/703.”
  • “By a hair…the top spot is 404(b).  It is powerful because 404(b) evidence has the potential to alter outcomes – sometimes rightly, sometimes wrongly.  Its influence can be outsized, and it can be hard for jurors to cabin 404(b) evidence so that it is used consistently with the intended purpose (which, of course, begs the question of whether the intended purpose is appropriate). Placing second by a hair is 501.  If I hadn’t paused to ponder this question, I doubt that 501 would have immediately come to mind.  But elevating principle over logical relevance makes the privilege rules extremely powerful – by skewing without acknowledgment the scope of information the jury is permitted to consider.”
  • “My vote is for FRE 401, because relevance always matters.  Even if there is an objection on some other basis, and that objection is overcome, relevance is always in play. I’d also argue that many other exceptions to other evidentiary prohibitions are grounded in a broad concept of relevance/reliability.”
  • “It all starts and many times ends with Rule 401 – it’s either relevant or it’s not.  End of essay.”
  • “Rule 105 – if you accept that juries actually follow a judge’s instructions, this rule — often in combination with Rule 403 — can bring in a lot of otherwise arguably inadmissible evidence with a caveat from the judge on how the limited purpose it was introduced. Rule 602 – this rule operates to exclude a lot of witnesses unless that person is an expert offering an opinion – I’m sure a lot of people would want to testify at a trial but they can’t unless they have personal knowledge.”
  • “I submit the most powerful evidence provision is Rule 403 because it confers upon a judge the extraordinary right to exclude proof that is otherwise relevant and probative. It is like drawing a curtain on stage so that the audience members, i.e., the jurors, are not exposed to a sideshow that will divert their attention from the main performance. As a close runner-up, I nominate Rule 802, because of its huge practical impact. The disallowance of most hearsay places heavy burdens on the parties to produce witnesses having first-hand knowledge to testify at the trial or hearing.”

All thoughtful answers.  Particularly intriguing is that involving Rule 501 and the idea of the power of privilege barring access to what may be the most probative evidence available in a case.  As to the vote for Rule 403, I differ not because of the Rule’s potential but because of its express limitations – evidence “may” be excluded when its value is “substantially” outweighed by any of the enumerated risks.

And only one volunteered my selection.  Approaching this from a litigation perspective, my selection is Rule 105.


105 reads as follows:

If the court admits evidence that is admissible against a party or for a purpose—but not against another party or for another purpose—the court, on timely request, must restrict the evidence to its proper scope and instruct the jury accordingly.

Delete the notion of “against a party” and the Rule addresses the situation “if the court admits evidence that is admissible for [one] purpose but not for another purpose…”

While the Rule’s use of “if” does not itself create an authority to admit evidence as long as it has one allowable use, it has been read as such.  Limited admissibility is “embodied in Rule 105…”  Lubbock Feed Lots, Inc. v. Iowa Beef Processors, Inc., 630 F.2d 250, 265 (5th Cir. 1980).   See also Davis v. Duran, 276 F.R.D. 227, 233 n.5 (N.D. Ill. 2011)(“ Rule 105 provides for limited admissibility…”).

The power of this Rule does not end with its tolerance of and approval for admitting evidence that has some legitimate purpose regardless of any number of improper ones; it increases exponentially with the “crucial assumption underlying that system is that juries will follow the instructions given them by the trial judge…”  Parker v. Randolph, 442 U.S. 62, 73, 99 S. Ct. 2132, 2139 (1979).

Lest there be any doubt of the power of Rule 105, consider the recent decision in
People v. Thomas, No. 326232, 2016 Mich. App. LEXIS 1506, at *5 (Ct. App. Aug. 11, 2016).  Thomas was charged with murder, but his DNA was not found on the gun; his codefendant’s DNA was found on the side of the gun along with inside of the barrel of the gun. Who fired the weapon that killed the victim was at issue in the case.

The prosecution was permitted to introduce evidence that Thomas had assaulted the codefendant weeks earlier by shoving the gun barrel into her mouth and down her throat.  In terms of the relevance of this evidence, the Michigan court explained that this

was material because it related to a fact of consequence (i.e., who had access to and used the murder weapon)…If defendant used the murder weapon to assault [codefendant], it shows that he had access to the murder weapon and made it more probable that he committed the instant offense with the murder weapon. Moreover, the fact that the gun was shoved down Dijana’s throat explains why her DNA was on the inside of the barrel and on the side of the gun.

And Rule 105’s role?  As the appellate court explained, “the trial court…gave a limiting instruction that the jury may only use this evidence to ‘think about whether this tends to show how the DNA of [codefendant] was found on the gun.’ This limiting instruction lessened the potential for prejudice because ‘jurors are presumed to follow their instructions.’”

In other words, an instruction along the lines of “don’t use the fact that he shoved a gun down someone else’s throat to show he is a bad, murderous guy but only to explain why the other person’s DNA is there” is presumed to suffice.  That is a POWERFUL rule.