Union violence is violence committed by unions or union members during labor disputes. When union violence has occurred, it has frequently been in the context of industrial unrest. Violence has ranged from isolated acts by individuals to wider campaigns of organised violence aimed at furthering union goals within an industrial dispute.
Anti-union violence has also occurred frequently in the context of industrial unrest, and has often involved the collusion of management and government authorities, private agencies, or citizens' groups in organising violence against unions and their members.
Protests and verbal abuse are routinely aimed against union members or replacement workers who cross picket lines ("blacklegs" or "scabs") during industrial disputes. The inherent aim of a union is to create a labor monopoly so as to balance the monopsony a large employer enjoys as a purchaser of labor. Strikebreakers threaten that goal and undermine the union's bargaining position, and occasionally this erupts into violent confrontation, with violence committed either by, or against, strikers. Some who have sought to explain such violence observe, if labor disputes are accompanied by violence, it may be because labor has no legal redress. In 1894, some workers declared:
..."the right of employers to manage their own business to suit themselves," is fast coming to mean in effect nothing less than a right to manage the country to suit themselves.
Occasionally, violent disputes occur between unions, when one union breaks another's strike.
Researchers in industrial relations, criminology, and wider cultural studies have examined violence by workers or trade unions in the context of industrial disputes. US and Australian government reports have examined violence during industrial disputes.
Main article: Union violence in the United States