Robert H. Jackson, International Union v. Wisconsin Employment Relations Board…
“ While the Federal Board is empowered to forbid a strike, when and because its purpose is one that the Federal Act made illegal, it has been given no power to forbid one because its method is illegal-even if the illegality were to consist of actual or threatened violence to persons or destruction of property. Policing of such conduct is left wholly to the states. In this case there was also evidence of considerable injury to property and intimidation of other employees by threats and no one questions the state's power to police coercion by those methods. ”
