February 8, 1989. June 21, 1989. Present: LIACOS, C.J., WILKINS, ABRAMS, NOLAN, LYNCH, JJ. Local 509, Service Employees International Union, AFL-CIO, CLC (Local 509) filed a brief as amicus curiae. Labor, Federal preemption. Jurisdiction, Labor case. Labor Relations Commission. Federal Preemption. Discussion of the construction given Section 14 (c) (1) of the National Labor Relations Act, 29 U.S.C. § 164 (c) (1), and the standards applied, by the National Labor Relations Board in the exercise of