Mitläufer is a German term (plural: Mitläufer) used in the denazification proceedings in West Germany after World War II to describe people who supported Nazism without directly participating in Nazi atrocities such as genocide. Mitläufer is usually translated in English as either "fellow-traveler" or "hanger-on".
http://www.woxikon.com/wort/mitl%C3%A4ufer.php Archived 2011-04-07 at the Wayback Machine