The impact that labor unions had on American industrial workers during this period was mixed at best. Most business owners in heavy industry took a hard line against unions in their factories, mills, and mines, and generally speaking, during this period, state governments, as well as the federal government, notably the courts, supported them. Indeed, it was during this period that the Sherman Antitrust Act, passed with the intent of curbing the formation of monopolies, was usually invoked to curb the formation of unions. Labor disputes often became violent, as a host of examples, including Homestead Steel, Ludlow, and the Pullman factory strikes attest. Labor unions were portrayed as un-American and radical, and the position of the federal government toward them was almost unfailingly hostile until Theodore Roosevelt's intervention in the anthracite coal miners' strike of 1902.
On the other hand, some state governments, particularly in areas with a heavy immigrant population, passed laws that met many industrial workers' broad demands for maximum work hours, better working conditions, and other reforms. But generally speaking, industrial labor unions struggled for existence before the turn of the century. While the Knights of Labor boasted a vast membership, its influence was somewhat limited, and the most powerful unions during the time were the more moderate craft unions, organized into the American Federation of Labor under Samuel Gompers.