The phrase "lunatic fringe" refers to the small group of people who hold extreme or radical views on a particular subject, often behaving in an irrational or fanatic way. Full definition
Keep preaching moderate views, maybe someone from the (pick your own lunatic fringe here) will hear you. (religion.blogs.cnn.com)
Unlike a number of the many lunatic fringe candidates on the GOP side, there was never any chance that he could have won the nomination. (religion.blogs.cnn.com)
Foundation Dale Jr: Member of Corvette Lunatic Fringe Corvette Featured in Chevy Super Bowl XLI Commercial (corvetteblogger.com)