Diane Drufenbrock

Diane Joyce Drufenbrock SSSF (October 7, 1929 – November 4, 2013), also known as Sister Madeleine Sophie, was an American religious sister as a member of the Catholic School Sisters of St. Francis. She was a Christian socialist who was the vice-presidential candidate for the Socialist Party USA in the 1980 United States presidential election.

Drufenbrock was born in Evansville, Indiana. In 1948, after graduating Reitz Memorial High School, she moved to Milwaukee, Wisconsin, to enter the Franciscan Sisters. A mathematics graduate of Alverno College in 1953 and of Marquette University, she taught mathematics at Alverno College, at the University of Wisconsin–Parkside, and elsewhere around Milwaukee, including at the then-new St. Joseph High School (Kenosha) when it opened in September 1957.

Drufenbrock gained a doctorate in mathematics from the University of Illinois at Urbana in 1963. After teaching for 13 years at Alverno College, she taught at Saint Mary-of-the-Woods College in her native Indiana for 18 years.

Her interest in social issues led her to join the Socialist Party USA in 1976. She ran as their vice-presidential candidate in the 1980 United States presidential election, and served as that party's National Treasurer. That campaign resulted in the Party's recognition by the Federal Elections Commission as a national political party.