lunatic fringe

plural lunatic fringes

1. archaichistoricalA woman's hairstyle in which the hair is cut square across the forehead.First known use 19th c.
2. A minority political or social group espousing extreme, fanatical, or irrational views.

   Among the wise and high-minded people who in self-respecting and genuine fashion strive earnestly for peace, there are the foolish fanatics always to be found in such a movement and always discrediting it — the men who form the lunatic fringe in all reform movements.

   1913, Theodore Roosevelt, Theodore Roosevelt — An Autobiography, ch. VII, page 211