"We have held that the state still may exercise `its historic powers over such traditionally local matters as public safety and order and the use of streets and highways.'"

"Furthermore, this Court has long insisted that an `intention of Congress to exclude States from exerting their police power must be clearly manifested.'(Napier

"[T] he state's exercise of its police power (eg, the prevention of mass picketing of the employer's factory, threatening personal injury or property damage to employees desiring to work, obstructing entrance to and egress from the employer's factory, obstructing the streets and public roads, picketing the homes of employees, and other breaches of the peace in connection …

—or regulation of this type of employee or union activity. The Committee Reports on the federal Act plainly indicate that it is not `a mere police court measure'and that authority of the several States may be exerted to control such conduct. Furthermore, this Court has long insisted that an `intention of Congress to exclude States from exerting their police power must be clearly …

—we held that employee and union conduct over which no direct or delegated federal power was exerted by the National Labor Relations Act is left open to regulation by the state.

This Court has consistently recognized the right of States to deal with violence and threats of violence appearing in labor disputes, sustaining a variety of remedial measures against the contention that state law was pre-empted by the passage of federal labor legislation.

"***[W] e start with the assumption that the historic police powers of the States were not to be superseded by the Federal Act unless that was the clear and manifest purpose of Congress.

By the exclusion of supervisory employees and the regulation of their collective bargaining rights from the federal act the field as to them was left open to state control

It is clear from the legislative history of the Taft-Hartley Act that in subjecting certain conduct to regulation as an unfair labor practice Congress had no intention of impairing a State's traditional powers to punish or in some instances prevent that same conduct when it was offensive to what a leading case termed "such traditionally local matters as public safety and order …

—to conduct affecting interstate commerce, and that state courts may enjoin mass picketing, threatening employees, obstructing streets and highways, picketing homes, blocking the entrance to or egress from a factory, coercing employees who wish to refrain from striking, interfering with others approaching an area where a strike is in progress, recurrent unannounced …