The Collaborative International Dictionary
Mugwumpism
Mugwumpery \Mug"wump`er*y\, Mugwumpism \Mug"wump*ism\, n. The acts and views of the mugwumps. [Political Cant, U.S.]
Wiktionary
mugwumpism
n. (context US politics slang English) The acts and views of the mugwumps.