Document ID: ./input/supremecourt_opinions/opinions/10pdf/09-893.pdf
Page Number: 8

Cite as:  563 U. S. ____ (2011) 

5 

Opinion of the Court 

agreements  on  an  equal  footing  with  other  contracts, 
Buckeye  Check  Cashing,  Inc.  v.  Cardegna,  546  U. S.  440, 
443 (2006), and enforce them according to their terms, Volt 
Information  Sciences,  Inc.  v.  Board  of  Trustees  of  Leland 
Stanford Junior Univ., 489 U. S. 468, 478 (1989).

The  final  phrase  of  §2,  however,  permits  arbitration
agreements  to  be  declared  unenforceable  “upon  such 
grounds  as  exist  at  law  or  in  equity  for  the  revocation  of
any  contract.”    This  saving  clause  permits  agreements  to
arbitrate  to  be  invalidated  by  “generally  applicable  con-
tract  defenses,  such  as  fraud,  duress,  or  unconscionabil-
ity,”  but  not  by  defenses  that  apply  only  to  arbitration  or 
that derive their meaning from the fact that an agreement 
to  arbitrate  is  at  issue.    Doctor’s  Associates,  Inc.  v. 
Casarotto,  517  U. S.  681,  687  (1996);  see  also  Perry  v. 
Thomas, 482 U. S. 483, 492–493, n. 9 (1987).  The question
in this case is whether §2 preempts California’s rule clas-
sifying  most  collective-arbitration  waivers  in  consumer
contracts  as  unconscionable.    We  refer  to  this  rule  as  the 
Discover Bank rule. 

Under  California  law,  courts  may  refuse  to  enforce  any
contract found “to have been unconscionable at the time it 
was  made,”  or  may  “limit  the  application  of  any  uncon-
scionable  clause.”  Cal.  Civ.  Code  Ann.  §1670.5(a)  (West 
1985).  A  finding  of  unconscionability  requires  “a  ‘proce-
dural’ and a ‘substantive’ element, the former focusing on
‘oppression’ or ‘surprise’ due to unequal bargaining power,
the latter on ‘overly harsh’ or ‘one-sided’ results.”  Armen-
dariz v. Foundation Health Pyschcare Servs., Inc., 24 Cal. 
4th  83,  114,  6  P. 3d  669,  690  (2000);  accord,  Discover 
Bank, 36 Cal. 4th, at 159–161, 113 P. 3d, at 1108. 

In Discover Bank, the California Supreme Court applied 
this  framework  to  class-action  waivers  in  arbitration 
agreements and held as follows: 

“[W]hen the waiver is found in a consumer contract of