Anti-union violence is physical force intended to harm union officials, union organizers, union members, union sympathizers, or their families. It is most commonly used either during union organizing efforts, or during strikes. The aim most often is to prevent a union from forming, to destroy an existing union, or to reduce the effectiveness of a union or a particular strike action. If strikers prevent people or goods to enter or leave a workplace, violence may be used to allow people and goods to pass the picket line.