the american railway union’s leader who was sentenced to federal prison for failing to abide by a court’s labor injunction, and later advocated the election of a government that would be responsive to the working class, based on his beliefs in socialism was:

Eugene Debs

Explanation:

Eugene Victor Debs (1855 - 1926), with four other ARU leaders, was detained and accused of being in contempt of court for failing to abide by a court’s labor injunction, by interfering with the railroads during the Chicago Pullman Palace Car Company strike. He was sentenced to six months in jail. Influenced by the works of Karl Marx, Debs became more and more critical of traditional politics and capitalism, and in 1896 he worked in the campaign of the presidential candidate William Jennings Bryan