In the 1910s and early 1920s, the IWW achieved many of its short-term goals, particularly in the American West, and cut across traditional guild and union lines to organize workers in a variety of trades and industries.

[14] The IWW promotes the concept of "One Big Union", and contends that all workers should be united as a social class to supplant capitalism and wage labor with industrial democracy.

This in turn exerted a political influence on the Swedish labor movement's left, that in 1910 formed the Syndicalist union SAC which soon contained a minority seeking to mimick the tactics and strategies of the IWW.

[27] Members of the IWW were active throughout the country and were involved in the Seattle General Strike of 1919,[28] were arrested or killed in the Everett Massacre,[29] organized among Mexican workers in the Southwest,[30] and became a large and powerful longshoremen's union in Philadelphia.

[9] When WFM executives Bill Haywood, George Pettibone, and Charles Moyer were accused of complicity in the murder of former Idaho governor Frank Steunenberg, the IWW used the case to raise funds and support and paid for the legal defense.

In what a contemporary writer pointed out was a complete reversal of their usual policy, UMWA officials called for police to protect United Mine Workers members who wished to cross the picket lines.

Demands included the doubling of pay for surface workers, most of them recent immigrants from Mexico, as well as changes in working conditions to make the mines safer.

[47] The IWW's efforts were met with "unparalleled" resistance from Federal, state and local governments in America;[10] from company management and labor spies, and from groups of citizens functioning as vigilantes.

[48][49] On November 5, 1916, at Everett, Washington, a group of deputized businessmen led by Sheriff Donald McRae attacked Wobblies on the steamer Verona, killing at least five union members[50] (six more were never accounted for and probably were lost in Puget Sound).

[53]: 241  This echoed the view, expressed at the IWW's founding convention, that war represents struggles among capitalists in which the rich become richer, and the working poor all too often die at the hands of other workers.

Yet when a declaration of war was passed by the U.S. Congress in April 1917, the IWW's general secretary-treasurer Bill Haywood became determined that the organization should adopt a low profile in order to avoid perceived threats to its existence.

After much debate on the General Executive Board, with Haywood advocating a low profile and GEB member Frank Little championing continued agitation, Ralph Chaplin brokered a compromise agreement.

[35]: 406  Minutes books, correspondence, mailing lists, and publications were seized, with the U.S. Department of Justice removing five tons of material from the IWW's General Office in Chicago alone.

[35]: 406 Based in large measure on the documents seized September 5, one hundred and sixty-six IWW leaders were indicted by a Federal Grand Jury in Chicago for conspiring to hinder the draft, encourage desertion, and intimidate others in connection with labor disputes, under the new Espionage Act.

Which side initiated the violence of the Centralia massacre is disputed, though there had been previous attacks on the IWW hall and businessmen's association had made threats against union members.

"[67] After the passage of the Taft-Hartley Act in 1946 by Congress, which called for the removal of Communist union leadership, the IWW experienced a loss of membership as differences of opinion occurred over how to respond to the challenge.

In Portland, Oregon, the IWW led campaigns at Winter Products (a brass plating plant) in 1972, at a local Winchell's Donuts (where a strike was waged and lost), at the Albina Day Care (where key union demands were won, including the firing of the director of the day care), of healthcare workers at West Side School and the Portland Medical Center, and of agricultural workers in 1974.

The campaign led to pay raises, the implementation of a grievance procedure, and medical and dental coverage, but the union failed to maintain its foothold, and in 1982 the CETA program was replaced by the Job Training Partnership Act.

The Chicago committee published a model contract which was distributed to musicians in the hopes of raising industry standards, as well as maintaining an active phone line for booking information.

IWW musicians such as Utah Phillips, Faith Petric, Bob Bovee, and Jim Ringer also toured and promoted the union,[71]: 17  and in 1987 an anthology album, Rebel Voices, was released.

In a workplace justice campaign called Focus on the Food Chain, carried out jointly with Brandworkers International, the IWW workers won settlements against employers including Pur Pac, Flaum Appetizing and Wild Edibles.

[86] In early 2011, Wisconsin Governor Scott Walker announced a budget bill which the IWW held would effectively outlaw unions for state or municipal workers.

[96] In June 2017, Burgerville paid a settlement of $10,000 after an investigation by the Oregon Bureau of Labor and Industries, which found that the company had violated state-mandated break periods for workers.

Two days later, on March 16, staff at the Ohio Valley Environmental Coalition (OVEC) announced their intent to unionize with the IWW, and requested voluntary recognition from management.

The 1908 split between the Chicago and Detroit factions in the United States was echoed by internal unrest in the Australian IWW from late 1908, resulting in the formation of a pro-Chicago local in Adelaide in May 1911 and another in Sydney six months later.

In December 1916, the Commonwealth government led by Labour Party renegade Billy Hughes declared the IWW an illegal organization under the Unlawful Associations Act.

[120] As an extreme example of the integration of ex-IWW militants into the mainstream labor movement one might instance the career of Donald Grant, one of the Sydney Twelve sentenced to fifteen years imprisonment for conspiracy to commit arson and other crimes.

Several Tasmanian Labour "groupings" in the 1890s cited their earlier New Zealand experience of activism e.g. later premier Robert Cosgrove, and also Chris Watson from New South Wales.

Several Canadian IWW members were killed in the Spanish Civil War and the CNT's ensuing defeat at the hands of both Fascist and Republican forces.

During the Spanish Civil War, a Wobbly from Neath, who had been active in Mexico, trained volunteers in preparation for the journey to Spain, where they joined the International Brigades to fight against Franco.