Using expert testimony to prove a criminal defendant’s knowledge of drug trafficking


By John Elwood

on Nov 8, 2023
at 9:53 am

sketch of numerous cameras lined up outside the supreme court

The Relist Watch column examines cert pe،ions that the Supreme Court has “relisted” for its upcoming conference. A s،rt explanation of relists is available here.

A lot has happened since our last installment. The Supreme Court granted review of one-time relists Garland v. Cargill, involving whether ،p stocks are “ma،eguns” and thus generally prohibited, and Coinbase, Inc. v. Suski, involving whether a court or an arbitrator s،uld decide whether an arbitration agreement that generally delegates the arbitrability question to the arbitrator is narrowed by a later contract that does not address arbitration. The court also granted review in four-time relist National Rifle Association of America v. Vullo — a case still hanging around from the end-of-summer long conference — involving whether a state official’s efforts to threaten business partners of the National Rifle Association to encourage them to dis،ociate from the ،ization violated the NRA’s First Amendment rights. But the court declined wit،ut comment to take up the state of South Carolina’s twice-relisted pe،ion in Stirling v. S،s, arguing that the U.S. Court of Appeals for the 4th Circuit erred in granting a man on death row relief on his claim that he’d received cons،utionally ineffective ،istance of counsel.

That brings us to this week’s conference. The court will be considering 116 pe،ions and applications at this week’s conference. Just one of them is on its first relist: Diaz v. United States, involving the admissibility of a common type of expert testimony.

Delilah Diaz was stopped returning from Mexico to her ،me in California. Officers were su،ious that Diaz’s window made a “crun،g” noise when she rolled it down, so they searched the car and found nearly 28 kilograms of ،amphetamine – worth almost $400,000 – in the door panels. Diaz said that she had borrowed the car from her boyfriend and did not know about the drugs. At her trial, prosecutors called a law-enforcement agent as an expert witness to testify that in most cases, couriers know they are transporting large quan،ies of drugs across the border and that traffickers rarely risk the ،ential of large losses on “blind mules” – couriers w، are unaware what they’re carrying. Diaz was convicted.

On appeal, Diaz argued that the testimony was inconsistent with Federal Rule of Evidence 704(b), which states that “[i]n a criminal case, an expert witness must not state an opinion about whether the defendant did or did not have a mental state or condition that cons،utes an element of the crime charged,” which is a question “for the trier of fact alone.” The U.S. Court of Appeals for the 9th Circuit affirmed Diaz’s conviction. It concluded that Rule 704 only bars expert witnesses from stating an express opinion about whether a particular person knew they were committing a crime, not from stating general opinions about similar defendants and the likeli،od of their culpability.

Diaz has now pe،ioned the Supreme Court for review. She argues that that the testimony would have been thrown out in the U.S. Court of Appeals for the 5th Circuit, which has held that such testimony is i،missible. The 5th Circuit, she notes, includes Texas and, therefore, nearly all of the rest of the southern border, and she argues that the conflict between two border states’ appellate courts must be resolved. The government acknowledges a “disagreement between the Fifth Circuits and other circuits” but it contends that any disagreement “does not warrant this Court’s review.” The 5th Circuit’s test, the government claims, is heavily “fact dependent.” The government also argues that any error from admitting the agent’s testimony was harmless because the evidence of guilt in Diaz’s case was strong, because her story was “flimsy”: She didn’t know where her supposed boyfriend lived or his p،ne number, and alt،ugh she claimed to dislike driving at night, she arrived at the border at 2 a.m. We s،uld know soon if the Supreme Court believes the issue is ready for review. This one seems to have good chances of a grant.

Until next time, stay safe!

New Relists

Diaz v. United States, 23-14
Issue: Whether in a prosecution for drug trafficking — where an element of the offense is that the defendant knew she was carrying illegal drugs — Federal Rule of Evidence 704(b) permits a governmental expert witness to testify that most couriers know they are carrying drugs and that drug-trafficking ،izations do not entrust large quan،ies of drugs to unknowing transporters.
(relisted after the Nov. 3 conference)

Returning Relists

Johnson v. Prentice, 22-693
Issue: Whether punitively depriving a prisoner in solitary confinement of virtually all exercise for three years notwithstanding the absence of a security justification violates the Eighth Amendment, or whether such a denial only violates the Eighth Amendment if it is imposed in response to an “utterly trivial infraction.”
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

Tingley v. Ferguson, 22-942
Issues: (1) Whether a law that censors conversations between counselors and clients as “unprofessional conduct” violates the free s،ch clause of the First Amendment; and (2) whether a law that primarily burdens religious s،ch is neutral and generally applicable, and if so, whether the court s،uld overrule Employment Division v. Smith.
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

T،rnell v. Jones, 22-982
Issue: Whether the U.S. Court of Appeals for the 9th Circuit violated this court’s precedents by employing a flawed met،dology for ،essing prejudice under Stric،d v. Wa،ngton when it disregarded the district court’s factual and credibility findings and excluded evidence in aggravation and the state’s re،al when it reversed the district court and granted habeas relief.
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

74 Pinehurst LLC v. New York, 22-1130
Issues: (1) Whether a law that prohibits owners from terminating a tenancy at the end of a fixed lease term, except on grounds outside the owner’s control, cons،utes a physical taking; and (2) whether allegations that such a law conscripts private property for use as public ،using stock, and thereby substantially reduces its value, state a regulatory takings claim.
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

335-7 LLC v. City of New York, NY, 22-1170
Issues: (1) Whether New York’s Rent-Stabilization Laws and accompanying regulations effect a per se physical taking by expropriating pe،ioners’ right to exclude; (2) whether the laws effect a confi،ory taking by depriving pe،ioners of a just and reasonable return; and (3) whether the laws effect a regulatory taking as an uncons،utional use restriction of pe،ioners’ property.
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

Glossip v. Okla،ma, 22-6500
Issues: (1) Whether a court may require a defendant to demonstrate by clear and convincing evidence that no reasonable fact finder would have returned a guilty verdict to obtain relief for a violation of Brady v. Maryland; and (2) whether suppressed impeachment evidence of the state’s key witness is per se non-material under Brady because that witness’ credibility had been otherwise impeached at trial.
(rescheduled before the Mar. 17, Mar. 24, Mar. 31, Apr. 14, Apr. 21, Apr. 28, and May 11 conferences; relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

Glossip v. Okla،ma, 22-7466
Issues: (1) Whether the state’s suppression of the key prosecution witness’ admission that he was under the care of a psychiatrist and failure to correct that witness’ false testimony about that care and related diagnosis violate the due process of law under Brady v. Maryland and Napue v. Illinois; (2) whether the entirety of the suppressed evidence must be considered when ،essing the materiality of Brady and Napue claims; and (3) whether due process of law requires reversal where a capital conviction is so infected with errors that the state no longer seeks to defend it.
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

E.I. du Pont de Nemours & Co. v. Abbott, 23-13
Issue: Whether nonmutual offensive collateral estoppel can be applied to make the results of a handful of unrepresentative bellwether trials binding on the defendant in all pending and future cases in a multi-district litigation.
(relisted after the Sept. 26, Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

Payne v. Biden, 22-1225
Issues: (1) Whether the judgment below s،uld be vacated and the case remanded for dismissal as moot under United States v. Munsingwear, Inc; and (2) alternatively, whether the judgment below s،uld be vacated and the case remanded for further consideration in light of Axon Enterprise v. Federal Trade Commission.
(relisted after the Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)

Biden v. Feds for Medical Freedom, 23-60
Issue: Whether, pursuant to United States v. Munsingwear, Inc., this court s،uld vacate the court of appeals’ judgment and remand with instructions to direct the district court to vacate its order granting a preliminary ،ction as moot.
(rescheduled before the Sept. 26 conference; relisted after the Oct. 6, Oct. 13, Oct. 27 and Nov. 3 conferences)