Document ID: ./input/supremecourt_opinions/opinions/23pdf/22-899_97be.pdf
Page Number: 44

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

13 

ALITO, J., concurring in judgment 

expert opinion that, based on the information in Rast’s re-
port and notes, the items she tested contained marijuana or
methamphetamine. 
In  so  answering,  he  would 
acknowledge that he relied on Rast’s report and lab notes 
to reach his opinion.  He could have also disclosed the infor-
mation in the report, if the court found that the probative 
value of that information substantially outweighed the risk
of  prejudice.  See  Fed.  Rule  Evid.  703.    But  he  could  not 
testify  that  any  of  the  information  in  the  report  was  cor-
rect—for  instance,  that  Rast  actually  performed  the  tests 
she recorded or that she did so correctly.  Nor could he tes-
tify  that  the  items  she  tested  were  the  ones  seized  from
Smith.  Longoni did not have personal knowledge of any of 
these  facts,  and  it  is  unclear  what  “reliable”  scientific 
“methods” could lead him to intuit their truth from Rast’s 
records.  Fed. Rule Evid. 702(c) (defining a permissible ex-
pert opinion).

The  strictures  of  the  Federal  Rules  here  track  the  re-
quirements of our Confrontation Clause precedents.  If Lon-
goni testified to the truth of the fact that Rast actually per-
formed the tests indicated in her report and notes and that
she  carried  out  those  tests  properly,  he  violated  the  Con-
frontation Clause—assuming, of course, that the notes were
“testimonial,” a question that the Court does not reach.  But 
he would also violate the Federal Rules, which do not allow 
experts to testify to the truth of inadmissible hearsay.  In 
other words, except for the question whether Rast’s report
was “testimonial,” the Federal Rules and the requirements
of the Confrontation Clause are the same.  This case thus 
offers no occasion to blow up the Federal Rules. 

As  it  happens,  I  agree  with  the  Court  that  Longoni
stepped over the line and at times testified to the truth of 
the matter asserted.  The prosecution asked Longoni on sev-
eral occasions to describe the tests that Rast performed or
to  swear  to  their  accuracy,  and  Longoni  played  along.  He
stated  as  fact  that  Rast  followed  the  lab’s  “typical  intake