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American Political Elections
A nonpartisan collection of information about elections, voting, and American political issues.
From the U.S. Senate website, this page provides resources on the political parties of the United States in relation to the Senate, with historical information on political parties as well as information on the two current major parties: The Democratic and Republican parties.
This website offers a breakdown of political party affiliations of members of the U.S. House of Representatives from 1789-present. Sources on how these numbers were derived are referenced.