The Supreme Mugwump is the title held by the head of the International Confederation of Wizards (ICW).
Babajide Akingbade became Supreme Mugwump after Dumbledore (Pm).
Mugwump is derived from the Native American Algonquian word mugquomp, meaning "big chief". It's modern meaning refers to a person who remains aloof or independent from politics (Oxford English Dictionary).
Lexicon list of International Government Officials
From the Web
Oxford Dictionaries blog: What on earth is a mugwump?