  The Role of Third-Parties in US History urlLink Third parties often focus on a single main issue and force it into the mainstream of American political life. It was third parties that first pressed for emancipation, female suffrage, prohibition, and an end to child labor. Socialist Eugene V. Debs lost both his 1912 and 1920 presidential runs, but much of his platform, like Social Security, ultimately formed the basis of the modern welfare state. - urlLink The Week 
