name a few of its prominent members?
Meyer London, Victor Berger, Morris Hillquit, to name a few.
Socialist Party of America
There were two Socialist members of Congress, Meyer London of New York City and Victor Berger of Milwaukee (a part of the sewer socialism movement, a major front in socialism, Milwaukee being the first and the only major city to elect a socialist mayor, which it did four times between 1910 and 1956); over 70 mayors; and many state legislators and city councilors. Its voting strength was greatest among recent Jewish, Finnish and German immigrants, coal miners and former populist farmers in the Midwest. From 1900 (before its formal union) to 1912, it ran Eugene V. Debs for President at each election. The best showing ever for a socialist ticket was in 1912, when Debs gained 901,551 total votes, or 6% of the popular vote. In 1920, Debs ran again, this time while imprisoned for opposing World War I and received 913,693 votes, 3.4% of the total.

Early political perspectives ranged from radical socialism to social democracy, with New York party leader Morris Hillquit and Congressman Berger
union leader who ran for president 5 times Eugene Victor "Gene" Debs to which party did he belong? Socialist Party of America when was the party founded? 1901 who founded it? UNANSWERABLE
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Socialist Party of America [SEP] Early history
From 1901 to the onset of World War I, the Socialist Party had numerous elected officials throughout the United States. There were two Socialist members of Congress, Meyer London of New York City and Victor Berger of Milwaukee (a part of the sewer socialism movement, a major front in socialism, Milwaukee being the first and the only major city to elect a socialist mayor, which it did four times between 1910 and 1956); over 70 mayors; and many state legislators and city councilors. Its voting strength was greatest among recent Jewish, Finnish and German immigrants, coal miners and former populist farmers in the Midwest.