On 1 May 1886 more than 190,000 American workers went on strike, demanding an eight-hour workday. Railroads and factories stopped, and by the end of the day 150,000 workers had earned a guarantee of shorter working hours. This was one of the greatest victories for organized labor, but it quickly turned into one of the most bitter defeats. At the McCormick Harvester Company plant in Chicago, which produced machinery to harvest wheat, fourteen hundred strikers demanding an eight-hour workday and daily wages of two dollars had been locked out since February. The Illinois state courts, supporting the company's right to negotiate contracts with its employees, turned a deaf ear to the pleas of the striking workers. In March the company brought in three hundred nonunion workers, protected by the police and Pinkerton detectives. On 3 May the strikers clashed with these "scab" workers and the police fired into the crowd...