Its actually according to Congress https://en.wikipedia.org/wiki/Federal_Arbitration_Act
Also http://slatestarcodex.com/2014/11/05/the-right-to-waive-your...
Also http://slatestarcodex.com/2014/11/05/the-right-to-waive-your...
"CHAP. 218.-An Act To make valid and enforceable written provisions or agreements for arbitration of disputes arising out of contracts, maritime transactions, or commerce among the States or Territories or with foreign nations."