Normally we seem to apply these terms to religious people in the non-Christian world. I am talking about a particular home-grown example I saw on last night's Charlie Rose show. The guest was former U.S. Representative and House Majority Leader Dick Armey. Armey is currently active as a leader of Freedomworks, a political organization that is a significant backer of the Tea Party movement.
I had never heard Dick Armey speak before, I only knew him by reputation. I must say that he turned out to be more intellectually honest than I expected, and in many ways this makes him scarier. Let me elaborate: I expected him to use any argument that was convenient as long as it supported his anti-Obama attacks. Instead he turned out to be remarkably consistent in his opposition to rules and government of almost any kind. He really believes this.
Armey holds extreme positions on personal liberty and the (lack of) need for government. He objects to almost any rule that would regulate personal behavior, with a few exceptions. He sees government's role as mainly enforcement of property rights and maintaining a stable currency. This puts him way over on the fringe of our political spectrum (maybe not among economists and pundits, but at least speaking of the general populace) but there is a sizable group with him. What I don't like is that he sees anyone who believes otherwise as a danger to the American way of life, and feels they must be stopped. This is fanaticism.
There is something wrong with holding a belief so strongly that you don't consider that you might possibly be mistaken, and that anyone who disagrees is unfit to govern. Charlie Rose called him out with outrageous quotes from speeches he made at CPAC (a recent far-right political convention) and he stood solidly behind those statements. These were things like saying that almost every official in Washington aggressively hates the constitution.
We are a democracy of many different types of people and belief systems. Any kind of government is by definition a compromise. This fanatical allegiance to a single idea leaves no room for any compromise and by nature is anti-democratic.