The Mugwumps were Republican political activists who bolted from the United States Republican Party by supporting Democratic candidate Grover Cleveland in the United States presidential election of 1884. They switched parties because they rejected the financial corruption associated with Republican candidate James G. Blaine. In a close election, the Mugwumps supposedly made the difference in New York state and swung the election to Cleveland. The jocular word mugwump, noted as early as 1832, is from Algonquian (Natick) mugquomp, "important person, kingpin" (from mugumquomp, "war leader") implying that they were "sanctimonious" or "holier-than-thou," in holding themselves aloof from party politics.
After the election, mugwump survived for more than a decade as an epithet for a party bolter in American politics. Many Mugwumps became Democrats or remained independents; most continued to support reform well into the 20th century. During the Third Party System, party loyalty was in high regard and independents were rare. Theodore Roosevelt stunned his upper class New York City friends by supporting Blaine in 1884; by rejecting the Mugwumps he kept alive his Republican party leadership, clearing the way for his own political aspirations.