Wordorigins.org

Like a lot of famous people, Theodore Roosevelt is often given credit for coining words he did not actually invent. The Oxford English Dictionary defines lunatic fringe as “a minority group of adherents to a political or other movement or set of beliefs,” and has a quotation from Roosevelt’s 1913 History as Literature as its first citation of the usage:

There is apt to be a lunatic fringe among the votaries of any forward movement.¹