Union violence in the United States is physical force used by labor unions in the United States, intended to harm employers, managers, replacement workers, union abstainers, sympathizers of the prior groups, or their families. On various occasions violence has been committed by unions or union members during labor disputes in the United States. 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.

According to labor historians and other scholars, the United States has had the bloodiest and most violent labor history of any industrial nation in the world, and there have been few industries which have been immune. Researchers in industrial relations, criminology, and wider cultural studies have examined violence by workers or trade unions in the context of industrial disputes. The US government has examined violence during industrial disputes.

Overview According to a 1969 study, no major labor organization in American history has ever openly advocated violence as a policy, although some, in the early part of the 20th century, systematically used violence, most notably the Western Federation of Miners, and the International Association of Bridge, Structural, Ornamental and Reinforcing Iron Workers. However, violence does occur in the context of industrial disputes. When violence has been committed by, or in the name of, the union, it has tended to be narrowly focused upon targets which are associated with the employer. Violence was greater in conflicts in which there was a question of whether union recognition would be extended.

Union violence most typically occurs in specific situations, and has more frequently been aimed at preventing replacement workers from taking jobs during a strike, than at managers or employers.

Protest and verbal abuse are routinely aimed against union members or replacement workers who cross picket lines ("blacklegs") 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., citing 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., citing the advisory committee of the Amalgamated Association of Iron and Steel Workers during the Homestead Strike

A 1969 study of labor conflict violence in the United States examined the era following the 1947 passage of the Taft-Hartley Act, and concluded that violence had substantially abated. In the 16 years from 1947 through 1962, 29 people died in labor conflicts, a rate much lower than in previous eras. The study noted that attacks on strikers by company guards had all but disappeared. They estimated from NLRB records that 80 to 100 acts of violence by union members or supporters occurred each year, most of the attacks on people being unplanned fights with strikebreakers crossing picket lines. In the 1960s, the most common complaint of union violence was of sabotage during labor disputes. Numerous incidents included dynamite explosions, but targeting property, and without any dynamite-related injuries.

19th century Great Railroad Strike of 1877

The great railroad strike of 1877 saw considerable violence by, and against, workers, and occurred before unions were widespread. It started on July 14 in Martinsburg, West Virginia, in response to the cutting of wages for the second time in a year by the Baltimore & Ohio Railroad (B&O). Striking workers would not allow any of the stock to roll until this second wage cut was revoked. West Virginia governor Henry M. Mathews sent in state militia units to restore train service, but the soldiers refused to use force against the strikers and the governor called for federal troops.

Violent street battles occurred in Maryland between the striking workers and the Maryland militia. When the outnumbered troops of the 6th Regiment fired on an attacking crowd, they killed 10 and wounded 25. The rioters injured several members of the militia, damaged engines and train cars, and burned portions of the train station. On July 21–22, the President sent federal troops and Marines to Baltimore to restore order.

In Pittsburgh, strikers threw rocks at militiamen, who bayoneted their antagonists, killing twenty people and wounding twenty-nine others.

In Reading, Pennsylvania, workers conducted mass marches, blocked rail traffic, committed trainyard arson, and burned a bridge. The state militia shot sixteen citizens in the Reading Railroad Massacre. The militia responsible for the shootings was mobilized by Reading Railroad management, not by local public officials.

Chicago was paralyzed when angry mobs of unemployed citizens wreaked havoc in the rail yards. The strike was eventually suppressed by thousands of vigilantes, National Guard, and federal troops.

Haymarket affair of 1886

In 1886 the Haymarket affair (also known as the Haymarket massacre or Haymarket riot) was a protest rally and subsequent violence on May 4 at the Haymarket Square in Chicago. The rally supported striking workers. When police began to disperse the public meeting, an unknown person threw a dynamite bomb into their midst. The bomb blast and ensuing gunfire resulted in the deaths of eight police officers, mostly from friendly fire, and an unknown number of civilians. In the internationally publicized legal proceedings that followed, eight anarchists were tried for murder. Four men were convicted and executed, and one committed suicide in prison, although the prosecution conceded none of the defendants had thrown the bomb.

The Haymarket affair is generally considered significant for the origin of international May Day observances for workers. The causes of the Haymarket Affair are still controversial, but can be traced in part to an incident the previous day, in which police fired into a crowd of agitated workers during shift change at the McCormick Works, where the regular work force was on strike, and at least two workers were killed. In popular literature, the Haymarket Affair inspired the caricature of "a bomb-throwing anarchist."

Illinois Governor John Peter Altgeld later pardoned the three living survivors of the Haymarket prosecution, concluding (as have subsequent scholars) that there had been a serious miscarriage of justice in their prosecutions.

Burlington strike of 1888 During the 1888 strike against the Chicago, Burlington and Quincy Railroad, workers were arrested for wrecking a train. When one of those arrested turned out to be a detective, organized labor argued that the detective had incited the others., citing Journal of United Labor, July 12, 1888.

Labor unrest in 1892 "In the 1890s violent outbreaks occurred in the North, South, and West, in small communities and metropolitan cities, testifying to the common attitudes of Americans in every part of the United States." Workers with different ethnic origins who worked under very different conditions in widely separated parts of the United States nonetheless responded with equal ferocity when unions came under attack. "Serious violence erupted in several major strikes of the 1890s, the question of union recognition being a factor in all of them."

1892 in particular was a year of considerable labor unrest. Governors of five states called out the national guard and/or the army to quell unrest—against miners in East Tennessee and in Coeur D'Alene, Idaho, where a shooting war followed the discovery of a labor spy, against switchmen in Buffalo, New York, against a general strike in New Orleans, Louisiana, and against the Homestead, Pennsylvania steel strike.

Coeur d'Alene, Idaho labor strike

The strike of 1892 in Coeur d'Alene, Idaho erupted in violence when a union miner was killed by mine guards, and was further inflamed when union miners discovered they had been infiltrated by a Pinkerton agent who had routinely provided union information to the mine owners.

On Sunday night, July 10, armed union miners gathered on the hills above the Frisco mine. More union miners were arriving from surrounding communities. At five in the morning, shots rang out, and the firing became continuous. Both sides blamed the other for starting the shooting. The union miners, exposed on the logged-off hillside, had not positioned themselves for a gunfight, while mine guards were able to shelter in buildings. The union men circled above the mill, and got into a position where they could send a box of black powder down the flume into one of the mine buildings. The building exploded, killing one company man and injuring several others. The union miners fired into a remaining structure where the guards had taken shelter. A second company man was killed, and sixty or so guards surrendered. Union men marched their prisoners to the union hall.

The violence caused the governor to declare Martial Law, and bring in six companies of the Idaho National Guard to "suppress insurrection and violence." Federal troops also arrived, and they confined six hundred miners in bullpens without any hearings or formal charges. Some were later "sent up" for violating injunctions, others for obstructing the United States mail.

Homestead Strike, and an assassination attempt

One of the most notorious incidents of violence against management occurred in 1892 during the Homestead Strike—one of the most violent industrial disputes in American history—when Alexander Berkman attempted to assassinate Henry Clay Frick, chairman of the Carnegie Steel Company and manager of the mill where the strike occurred. Frick had locked out the workers, and later hired three hundred armed guards from the Pinkerton Detective Agency to break the union's picket lines, resulting in gunfire and flaming barges on the Ohio River. There was a consensus of all parties that the presence of the Pinkertons inflamed the attitudes of the strikers. The strikers defeated the Pinkertons, but could not keep the mills from operating after the National Guard was deployed.

Berkman, an avowed anarchist, had no connection to the union involved in the strike, but believed he was acting in the workers' interests. He was motivated by newspaper reports of,

...Henry Clay Frick, whose attitude toward labor is implacably hostile; his secret military preparations while designedly prolonging the peace negotiations with the Amalgamated; the fortification of the Homestead steel-works; the erection of a high board fence, capped by barbed wire and provided with loopholes for sharpshooters; the hiring of an army of Pinkerton thugs; the attempt to smuggle them, in the dead of night, into Homestead; and, finally, the terrible carnage.

Berkman's attack, called an attentat by the anarchists, injured but failed to kill Frick. Having anticipated that his act would launch a worker uprising, Berkman was surprised when a carpenter hit him with a hammer after he had been restrained. The attempted murder alienated the anarchist community from much of the labor movement, as well as dividing the anarchist community itself. Frick had been widely hated, but in at least one analysis, becoming the victim of such an attack transformed him into a "folk hero" in the public view.