“Using criminal violence to push [an extremist] cause only ups the odds that other zealots, holding very different views . . . may strike in the same way.”

—Karl Brooks, High Country News, December 7, 1998.

Political ideologies can be visualized as points on a straight line, with liberals to the left of center and conservatives to the right. Located near the center of the line are political moderates. At the far points at either end are the extremists, both liberal and conservative.

Liberals and conservatives differ primarily in their view of the proper role of government in the lives of citizens. While liberals tend to favor the federal government taking an active role in correcting social inequities, regulating business activities, and protecting the environment, conservatives tend to mistrust federal interference in these affairs. Conservatives believe that, to the extent that any regulation is necessary, these functions are best performed by...