. . . Doesn’t Have To Raise In Complaint, With District Court Deciding the Issue.
Smith v. JEM Group, Inc., Case No. 11-35964 (9th Cir. Dec. 12, 2013) (published) is a case deciding that a plaintiff opposing arbitration can challenge the validity in an opposition to compel arbitration by the defense, rather than raising the challenge in the complaint. That will do, according to the Ninth Circuit, meaning that the district judge–not the arbitrator–rules on the issue, distinct from a challenge to the entire contract.
For an more in-depth discussion, see co-contributor Marc’s December 18, 2013 post in his blog, California Mediation and Arbitration.