The federal government intervened, obtaining an injunction against the strike on the grounds that the strikers had obstructed the US Mail, carried on Pullman cars, by refusing to show up for work. President Grover Cleveland, whom Debs had supported in all three of his presidential campaigns, sent the United States Army to enforce the injunction. The presence of the army was enough to break the strike. Overall, 30 strikers were killed in the strike, 13 of them in Chicago, and thousands were blacklisted. An estimated $80 million worth of property was damaged and Debs was found guilty of contempt of court for violating the injunction and sent to federal prison.