In the Dictionary of Political Thought, Roger Scruton defines extremism as:
- Taking a political idea to its limits, regardless of unfortunate repercussions, impracticalities, arguments, and feelings to the contrary, and with the intention not only to confront, but to eliminate opposition.
- Intolerance toward all views other than one’s own.
- Adoption of means to political ends which show disregard for the life, liberty, and unalienable human rights of others. 
John George and Laird Wilcox, two of the foremost analysts of left-wing and right-wing extremism, state that this definition reflects a common proposition about extremist behavior: it is more an “issue of style than of content.” What the extremist believes is less important than what behavior he exhibits. Rather, extremism can cut across the political spectrum. George and Wilcox look at extremists as persons psychologically prone to extremism, regardless of political affiliation:
|“||Both of us have had the feeling many times that the Bircher with whom we were talking could just as easily have been a Communist and vice versa. It may be merely a question of who “gets to them” first. We tend to view the existence of an extremism-prone personality as a more reasonable hypothesis than attempts to account for the “pathology” of a particular point of view.||”|
|“||The relative ease with which a young communist could be converted into a National Socialist or vice versa was well known, best of all to the propagandists of the two parties. ||”|
Most people can hold radical or unorthodox beliefs in a more or less reasonable and rational manner. Extremists present their views in uncompromising, bullying, and often authoritarian or dictatorial ways.  American politician and United States Senator, Barry Goldwater highlighted the reasonable and rational use of extremism, by which most people would apply extreme measures, when he said:
|“||I would remind you that extremism, in the defense of liberty, is no vice! And let me remind you also that moderation, in the pursuit of justice, is no virtue! ||”|
Traits of the extremist
George and Wilcox look at extremists as persons psychologically prone to extremism, regardless of political affiliation: Both of us have had the feeling many times that the Bircher with whom we were talking could just as easily have been a Communist and vice versa. It may be merely a question of who “gets to them” first. We tend to view the existence of an extremism-prone personality as a more reasonable hypothesis than attempts to account for the “pathology” of a particular point of view. George and Wilcox list twenty-two common traits of extremists. While all people exhibit some of these traits at times, the important distinction is that “[with bona fide extremists, these lapses are not occasional.” The traits are:
- (1) character assassination;
- (2) name calling and labeling;
- (3) irresponsible sweeping generalizations;
- (4) inadequate proof for assertions;
- (5) advocacy of double standards;
- (6) tendency to view opponents and critics as essentially evil;
- (7) Manichean worldview;
- (8) advocacy of some degree of censorship or repression of opponents and/or critics;
- (9) a tendency to identify themselves in terms of who their enemies are: whom they hate and who hates them;
- (10) tendency toward argument by intimidation;
- (11) use of slogans, buzzwords, and thought stopping clichés;
- (12) assumption of moral or other superiority over others;
- (13) doomsday thinking;
- (14) a belief that doing bad things in the service of a “good” cause is permissible (ends justifies the means);
- (15) emphasis on [[[emotional]] responses, and, correspondingly, less importance to reasoning and logical analysis;
- (16) hypersensitivity and vigilance;
- (17) use of supernatural rationale for beliefs and actions;
- (18) problems tolerating ambiguity and uncertainty;
- (19) inclination toward "groupthink";
- (20) tendency to personalize hostility;
- (21) a feeling that the “system” is no good unless they win; and
- (22) tendency to believe in far-reaching conspiracy theories.
- Roger Scruton, Dictionary of Political Thought, p. 164. (1982).
- John George & Laird Wilcox, American Extremists: Militias, Supremacists, Klansmen, Communists and Others, pg. 54, Prometheus Books, 1996 (ISBN 1-57392-058-4). George is a professor of political science at the University of Central Oklahoma. Wilcox is the founder of the Wilcox Collection on Contemporary Political Movements at the University of Kansas, one of the largest of its kind in the world, which contains hundreds of thousands of documents on all political movements. He is also editor and publisher of annual guides on extremism. See Laird Wilcox, Guide to the American Right and Guide to the American Left (1997).
- George & Wilcox, n.30 p. 66.
- Road to Serfdom, Friedrich A. Hayek, Reader's Digest Condensed Version, April 1945, pg. 40.
- George & Wilcox, p. 54.
- Barry Goldwater Quotes