At the turn of the 20th century, industrial expansion was the apple of America’s eye. Factories churned out products from silverware to guns to cars at a breakneck pace. A web of railroads tied the country together. Cities began to expand not just out, but up, with the development of skyscrapers. All of these advances were made possible by a single commodity—steel.

Although the steel industry had remained competitive during the 1800s, in 1901, financial giant J.P. Morgan purchased and merged the Carnegie Steel Company, Federal Steel Company, and National Steel Company to form the U.S. Steel Corporation. The company was a juggernaut of American business from the moment of its creation: In its first year of operation, U.S. Steel—the world’s first billion-dollar corporation—produced 67% of the nation’s total steel output.

The formation of U.S. Steel spelled disaster for the Amalgamated Association of Iron, Steel, and Tin Workers (The AA). The union, which represented both skilled ironworkers and steelworkers, quickly realized that U.S. Steel’s size would allow it to crush any efforts for unionization or labor reform among its workforce, and it launched an unsuccessful strike in a last-ditch attempt to win recognition. The severely weakened AA went largely dormant until the end of World War One.

In 1919, a wave of anti-union sentiment bubbled across the country as unions were denied the necessary permits to hold meetings, and the infamous Pinkerton Detective Agency sent men to harass union members. The AA and its ally, the American Federation of Labor (AFL), responded by launching a strike in September of that year. Workers nationwide walked off the job, shutting down practically all the mills in the cities of Pueblo, Colorado; Chicago, Illinois; Wheeling, West Virginia; Johnstown, Pennsylvania; Cleveland, Ohio; Lackawanna, New York; and Youngstown, Ohio.

U.S. Steel and other companies hit by the strike used public opinion as a weapon against the strikers, playing on anti-communist and anti-immigrant attitudes to turn people against the unions and workers. They brought in strikebreakers to work the factories, demoralizing the workers on the picket lines. Furthermore, state and local governments deployed force against striking workers in favor of the companies; hundreds were beaten and arrested in an attempt to intimidate them back to work.

In the face of such retribution from companies, strikers began returning to work in October and November, and by January 1920, the nationwide steelworkers’ strike had completely collapsed. U.S. Steel had successfully beaten back the efforts of the AA and AFL, leaving the former completely decimated. The strike proved to be a major victory for business interests, which did not face serious labor unrest throughout the Roaring Twenties.