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CASSIRER v. THYSSEN-BORNEMISZA COLLECTION 
FOUNDATION 
Syllabus 

could go forward.  To determine what property law governed the dis-
pute, the courts below had to apply a choice-of-law rule.  The Cassirer 
plaintiffs urged the use of California’s choice-of-law rule; the Founda-
tion advocated a rule based in federal common law.  The courts below 
picked the federal option.  That option, they then held, commanded use
of  the  property  law  of  Spain,  not  California.    Applying  Spanish  law, 
the  courts  determined  that  the  Foundation  was  the  rightful  owner. 
This Court granted certiorari to resolve a conflict among the Courts of 
Appeals as to what choice-of-law rule a court should apply in an FSIA
case raising non-federal claims. 

Held: In an FSIA suit raising non-federal claims against a foreign state
or instrumentality, a court should determine the substantive law by 
using the same choice-of-law rule applicable in a similar suit against 
a private party.  Here, that means applying the forum State’s choice-
of-law rule, not a rule deriving from federal common law. 

The FSIA provides a baseline principle of foreign sovereign immun-
ity  from  civil  actions  unless  a  statutory  exception  applies  (including
the  expropriation  exception  found  to  apply  here).    See  §§1604–1607. 
Yet the FSIA was never “intended to affect the substantive law deter-
mining the liability of a foreign state or instrumentality” deemed ame-
nable to suit.  First Nat. City Bank v. Banco Para el Comercio Exterior 
de Cuba, 462 U. S. 611, 620.  To the contrary, Section 1606 of the stat-
ute provides: “As to any claim for relief with respect to which a foreign 
state is not entitled to immunity under [the FSIA], the foreign state
shall be liable in the same manner and to the same extent as a private 
individual under like circumstances.”  When a foreign state is not im-
mune from suit, it is  subject to the same  rules of liability (the same 
substantive law) as a private party.  See First Nat. City Bank, at 622, 
n. 11. 

Section  1606  dictates  the  selection  of  a  choice-of-law  rule:  It  must 
mirror the rule that would apply in a similar suit between private par-
ties.  Only the same choice-of-law rule can guarantee use of the same
substantive law—and thus guarantee the same liability.  Consider two 
suits seeking recovery of a painting: one suit against a foreign-state-
controlled museum (as here), the other against a private museum.  If 
the choice-of-law rules in the two suits differed, so might the substan-
tive law chosen.  And if the substantive law differed, so might the suits’ 
outcomes.  Contrary to Section 1606, the two museums would not be 
“liable to the same manner and to the same extent.” 

In this case, Section 1606 requires the use of California’s choice-of-
law  rule—because  that  is  the  rule  a  court  would  use  in  comparable 
private litigation.  Consider the just-hypothesized suit against a pri-
vate  museum,  brought  as  this  case  was  in  California  and  asserting