In the late nineteenth century, steel tycoon Andrew Carnegie's corporation had succeeded in preventing the formation of the Iron and Steelworkers Union by employing violent and devious tactics. At the famous Battle of Homestead, hundreds of strikers had been wounded, and a dozen killed, after violence erupted. Additionally, thousands of workers were blacklisted from working at the steel mills as punishment for their participation in the strike. Conditions in the steel mills, therefore, failed to improve for many years, until the American Federation of Labor (AFL) decided to attempt another organizing drive in 1918. Mother Jones immediately offered her assistance to the National Committee that had been created specifically for this unionization drive. One of the most critical problems in organizing the steelworkers was their inability to speak English. The steel corporation had preyed for years on immigrants, who were easily exploited, and had even used its name, the United States Steel Corporation, to scare the immigrants into thinking that the corporation was actually a branch of the government.
Traveling along the Monongahela River in Pennsylvania, Mother Jones gave numerous speeches and held rallies in support of the union. The workers came in large numbers and listened attentively to what she had to say. When the steel corporation forbade meetings, Mother Jones led workers to Ohio, where the steel corporation had less power. The United States Steel Corporation, led by President Elbert Gary, used every possible intimidation tactic to remain in control of its workers and to create distrust of the union. Mother Jones was arrested in Homestead in the middle of a speech. Workers rallied around the county jail to demand her release. After a quick trial, Mother Jones was heavily fined, but she continued her unionization efforts. Her work, along with the efforts of other union organizers, succeeded in bringing over 100,000 workers into the union by the summer of 1919. President Gary, however, repeatedly refused to negotiate, even though President Wilson himself urged Gary toward arbitration.
Union members voted to strike if efforts to negotiate were met with refusal, and on September 22, 1919, 400,000 workers walked out of work. The strike was difficult to organize and coordinate because the strikers were spread out between fifty towns and ten states, and the strikers faced all manner of harassment. Court-ordered injunctions made it illegal to have meetings, and groups of more than three people on the street were quickly and violently broken up. Company spies hindered efforts by union organizers to keep strikers aware of the situation. No means of communication or correspondence was allowed, and workers themselves were so intimidated by company guards that they often did not leave their homes.
The company also attempted to link the strike to the newly formed Soviet Union, claiming that the strike indicated that revolutionaries were infiltrating the United States. Many newspapers sided with the steel corporation against the foreign strikers, and the company soon turned public opinion against the strikers. The strikers felt even more isolated, and the Pennsylvania Coal and Iron Police saw plenty of opportunity to use their authority mercilessly. Guards even chased children so that they would be too intimidated to venture out of their homes. Continuous raids, which resulted in the murder of twenty-six union organizers and strikers, further prevented the strike from being successful. The strike began to collapse in the face of the relentless violence of the United States Steel Corporation and President Gary's ruthlessness and obstinacy. By January of 1920, the steelworkers went back to work without any concessions. They continued supporting their families on miserly wages and the continued to work long hours in dangerous environments.