Record contained sufficient evidence to support Bd. determination that union, as exclusive source of referrals for their members, violated NLRA by failing to consistently use objective criteria when referring union members and discriminating against particular union member by passing him over on job referral list due to his status as political adversary of union president. Ct. rejected union’s argument that it did not operate exclusive hiring-hall where union had only 48-hour exclusive period to make said referrals, since record showed that employer had practice of hiring only those individuals whom union referred. Moreover, record showed that union used subjective and discretionary criteria when making said referrals. Also, ALJ could properly find that union discriminated against union member based on his political views where: (1) union leadership was aware of member’s political activities and made derogatory comments about member during most recent union election; (2) member and union president clashed during grievance process involving instant claim; and (3) union failed to show that non-referral of member would have occurred absent member’s political activities.