Williams v. Illinois
The Supreme Court upheld a rape conviction where a state DNA expert testified that an outside lab's DNA profile matched the defendant, even though the outside analyst never testified and could not be cross-examined.
The fractured 4-1-4 decision leaves lower courts without a clear rule for when crime-lab reports trigger a defendant's right to confront the analyst who produced them, since no single rationale commanded five votes.
“Out-of-court statements that are related by the expert solely for the purpose of explaining the assumptions on which that opinion rests are not offered for their truth and thus fall outside the scope of the Confrontation Clause.”
The plurality's core rationale for why the expert's reference to the outside lab's DNA profile did not violate the Confrontation Clause.
How it got here: A state trial judge convicted the defendant after a bench trial; Illinois's appellate court and supreme court both affirmed, and the Supreme Court agreed to review the confrontation issue.
The Case in Depth
What happened
A young woman was abducted and raped in Chicago. Vaginal swabs taken from her were sent to Cellmark, a private lab, which produced a male DNA profile. A state forensic analyst later testified at the defendant's bench trial that this profile matched a profile made from the defendant's blood, though she had not performed or observed the Cellmark testing herself.
The question before the Court
Could a lab expert tell a judge that DNA test results from an outside lab matched the defendant, without the defendant ever getting to question the analyst who ran that outside test?
The Court's answer
Yes — a plurality of the Court held that an expert witness may describe another lab's DNA test results as the basis for her own opinion, without violating the defendant's right to confront witnesses, so long as those results are not admitted as proof of their own truth. Because the DNA profile from the outside lab was used only to explain how the testifying expert reached her matching conclusion, and the case was tried before a judge rather than a jury, the plurality found no constitutional problem.
However, this was not a majority rationale. Four Justices dissented entirely, and a fifth Justice agreed only with the outcome, reasoning instead that the outside lab's report was too informal to count as the kind of statement the Confrontation Clause protects against. So while the conviction was upheld, the Court did not agree on why, leaving the underlying legal question unsettled for future cases.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Prosecutors can continue using DNA profiles produced by outside labs by having a different, in-house expert testify about the match, without calling every lab technician to the stand. Defendants challenging forensic evidence may find it harder to cross-examine the specific analysts whose work underlies a DNA match, since the Court did not require it here.
What changes now
This is a final merits decision, so the defendant's conviction stands as affirmed. Because no opinion attracted five votes on a single rationale, lower courts are left to sort out on their own when expert testimony about outside lab reports satisfies the Confrontation Clause, and the case did not establish a clear, uniformly applicable rule for future forensic-evidence disputes.
What this does not decide
Because no opinion commanded five votes for one rationale, the decision does not establish a clear, generally applicable rule for when forensic lab reports trigger the right to confront the analyst who produced them. The plurality's reasoning binds only four Justices, and the concurring Justice reached the same result for entirely different reasons.
Concurrences and dissents
Concurrence — Justice Breyer
Justice Breyer agreed with the outcome but argued the Court had not adequately addressed the harder underlying question of how the Confrontation Clause applies to the many layered technical statements made by multiple lab technicians during DNA testing. He would have ordered reargument to address that broader question, and in the meantime relied on his own dissenting views from two earlier cases to conclude the Cellmark report was not testimonial.
Concurrence — Justice Thomas
Justice Thomas agreed the conviction should stand but rejected the plurality's reasoning entirely, siding with the dissent that the Cellmark statements were used for their truth. He concluded there was no Confrontation Clause violation only because the Cellmark report lacked the formality and solemnity of a sworn or certified statement, unlike the reports in prior cases the Court had found unconstitutional.
Dissent — Justice Kagan
“What a neat trick—but really, what a way to run a criminal justice system.”Kagan's objection that the plurality's reasoning lets prosecutors sidestep a defendant's right to confront the analyst who did the testing.
Justice Kagan argued this was an open-and-shut case under prior precedent: the expert's testimony was functionally identical to the surrogate testimony already rejected in an earlier case, and the defendant never got to cross-examine the analyst who actually produced the DNA match. She warned the plurality's approach lets prosecutors evade the Confrontation Clause through relabeling and would have simply followed the Court's existing precedents.
How the Court got there
The legal reasoning, step by step
- The plurality applied the longstanding rule that experts may base opinions on facts they did not personally observe, so long as those facts are only used to explain the opinion's basis and not offered to prove the truth of the underlying facts themselves.
- Because the Illinois expert's reference to Cellmark's DNA profile was, in the plurality's view, only background explaining her own comparison opinion rather than proof that the sample truly came from the victim's swabs, the plurality treated it as falling outside the hearsay-like use the Confrontation Clause — the right to confront in-court accusers — was designed to police.
- As a second, independent ground, the plurality reasoned that even if the Cellmark report had been treated as substantive evidence, it would not count as a formal accusatory statement targeting a specific suspect, since it was generated before the defendant was identified and aimed at finding an unknown attacker rather than building a case against him.
- Four dissenting Justices countered that an expert's recitation of another lab's results is useful to the factfinder only if those results are true, so the report was necessarily used for its truth, meaning the defendant should have had the chance to cross-examine the actual Cellmark analyst.
- A separate concurrence agreed with the outcome but on the narrower ground that the Cellmark report was not sworn, certified, or otherwise formal enough to count as 'testimonial' in the first place, regardless of why it was introduced.
- With five Justices in various opinions rejecting the plurality's own reasoning, the case produced a judgment for the State without any single legal rule commanding majority support.
Doctrinal impact
Cases affected by this decision
Distinguishes Melendez-Diaz v. Massachusetts (557 U. S. 305)
The plurality said this case differs because the DNA profile was not admitted into evidence itself, unlike the sworn drug certificates there.
Distinguishes Bullcoming v. New Mexico (564 U. S. ___)
The plurality distinguished the unsworn but certified blood-alcohol report from the less formal Cellmark DNA report.
Reaffirms Tennessee v. Street (471 U. S. 409)
The plurality relied on this case's rule that statements used for a non-truth purpose don't trigger the Confrontation Clause.