9 U.S.C. § 2 : US Code - Section 2: Validity, irrevocability, and enforcement of agreements to arbitrate

      A written provision in any maritime transaction or a contract
    evidencing a transaction involving commerce to settle by
    arbitration a controversy thereafter arising out of such contract
    or transaction, or the refusal to perform the whole or any part
    thereof, or an agreement in writing to submit to arbitration an
    existing controversy arising out of such a contract, transaction,
    or refusal, shall be valid, irrevocable, and enforceable, save upon
    such grounds as exist at law or in equity for the revocation of any
    contract.