Document ID: ./input/supremecourt_opinions/opinions/23pdf/22-899_97be.pdf
Page Number: 18

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

15 

Opinion of the Court 

D. Bernstein, A. Ferguson, M. Wittlin, & J. Mnookin, The 
New Wigmore: Expert Evidence §5.4.1, p. 271 (3d ed. 2021).
If  believed  true,  that  basis  evidence  will  lead  the  jury  to
credit the opinion; if believed false, it will do the opposite.
See Williams, 567 U. S., at 106, and n. 1 (THOMAS, J., con-
curring in judgment); id., at 126–127 (KAGAN, J., dissent-
ing).  But  that  very  fact  is  what  raises  the  Confrontation 
Clause problem.  For the defendant has no opportunity to
challenge the veracity of the out-of-court assertions that are 
doing much of the work.

And if  that explanation seems a bit abstract, then take
this case as its almost-too-perfect illustration.  Recall that 
Rast tested eight seized items before she disappeared from
the scene.  At trial, the prosecutor asked the State’s “sub-
stitute expert” Longoni to testify about four of them (with
the rest dropping out of the case).  App. to Pet. for Cert. 26a.
A  recap  of  their  exchange  about  one  item  will  be  enough; 
the rest followed the same pattern.  Remember as you read
that Longoni, though familiar with the lab’s general prac-
tices, had no personal knowledge about Rast’s testing of the
seized items.  Rather, as his testimony makes clear, what
he knew on that score came only from reviewing Rast’s rec-
ords.  With that as background: 

Q Turn your attention to Item 26.  I’m going to hand
you what’s  been marked as State’s Exhibit 98 [Rast’s 
notes]. . . .  Did you review how [Item] 26 was tested in 
this case? 
A Yes. 
Q  When  you  reviewed  it,  did  you  notice  whether  the
[standard lab] policies and practices that you have just 
described were followed? 
A Yes. 
Q Were they followed?
A Yes. 
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