The Supreme Court of the United States has held that the Norris-LaGuardia Act prohibits a federal district court from enjoining a sympathy strike, notwithstanding arbitration provisions and an express no-strike clause in the collective bargaining agreement, since the strike is not over a grievance which the parties agreed to submit to arbitration.
Buffalo Forge Co. v. United Steelworkers, 96 S. Ct. 3141 (1976).
George C. Werner,
Labor Law - Norris-LaGuardia Act - Sympathy Strikes - Injunctions,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol15/iss2/11