Document ID: ./input/supremecourt_opinions/opinions/23pdf/22-899_97be.pdf
Page Number: 3

Cite as:  602 U. S. ____ (2024) 

3 

Syllabus 

true, then the statement has been offered for the truth of what it as-
serts.  The truth of the basis testimony is what makes it useful to the 
State;  that  is  what  supplies  the  predicate  for—and  thus  gives  value 
to—the state expert’s opinion.  And from the factfinder’s perspective, 
the jury cannot decide whether the expert’s opinion is credible without
evaluating the truth of the factual assertions on which it is based.  But 
that is what raises the Confrontation Clause problem.  For the defend-
ant has no opportunity to challenge the veracity of the out-of-court as-
sertions that are doing much of the work. 

Here, Rast’s statements came in for their truth, and no less because 
they were admitted to show the basis of Longoni’s expert opinions.  All 
of  Longoni’s  opinions  were  predicated  on  the  truth  of  Rast’s  factual 
statements.    And  the  jury  could  credit  those  opinions  because  it  too 
accepted the truth of what Rast reported about her lab work.  So the 
State’s basis evidence—more precisely, the truth of the statements on 
which its expert relied—propped up the whole case; yet the maker of
the statements was not in the courtroom, and Smith could not ask her 
any questions.  Pp. 11–19.

(b) What  remains  is  whether  the  out-of-court  statements  Longoni 
conveyed were testimonial.  The testimonial issue focuses on the “pri-
mary purpose” of the statement, and in particular on how it relates to
a future criminal proceeding.  But that issue is not now fit for resolu-
tion by this Court.  The question presented in Smith’s petition for cer-
tiorari took as a given that Rast’s out-of-court statements were testi-
monial,  and  the  Arizona  Court  of  Appeals  did  not  decide  the  issue.
Indeed, there may not remain a matter to decide, as Smith maintains
that the State has forfeited any argument that Rast’s statements were 
not testimonial.  The testimonial issue, including the threshold forfei-
ture  question,  is  thus  best  considered  by  the  state  court  in  the  first 
instance.  Pp. 19–22. 

Vacated and remanded. 

KAGAN,  J.,  delivered  the  opinion  of  the  Court,  in  which  SOTOMAYOR, 
KAVANAUGH, BARRETT, and JACKSON, JJ., joined, and in which THOMAS 
and GORSUCH, JJ., joined as to Parts I, II, and IV.  THOMAS, J., and GOR-
SUCH,  J.,  filed  opinions  concurring  in  part.    ALITO,  J.,  filed  an  opinion
concurring in the judgment, in which ROBERTS, C. J., joined.