(December 1, 2015, 1:25 PM EST) -- BOSTON — A reinsurer and its reinsured insurer argued recently in a federal court in Massachusetts over whether the reinsurer’s party-appointed arbitrator should be disqualified because of his employment history (John Hancock Life Insurance Company [U.S.A.] v. Employers Reassurance Corporation, No. 15-cv-13626, D. Mass.)....