Barclay's Ice Cream Co. v. Local No. 757 of the Ice Cream Drivers & Employees Union

We reject the proposition that under the doctrine of pre-emption our State courts must defer in this case to the exclusive competence of the National Labor Relations Board and thus are powerless to protect against the unlawful coercive activity designed by this union to erect an embargo on the flow of out-of-State goods into New York.

The Appellate Division reversed the order of Special Term (which had denied plaintiffs motion for a preliminary injunction) on the law and in the exercise of discretion, and restrained defendants pendente lite from picketing and distributing written material…