Our chapter on public opinion discusses the ideological beliefs of the general public. Gallup reports:
Political ideology in the U.S. held steady in 2011, with 40% of Americans continuing to describe their views as conservative, 35% as moderate, and 21% as liberal. This marks the third straight year that conservatives have outnumbered moderates, after more than a decade in which moderates mainly tied or outnumbered conservatives.
The percentage of Americans calling themselves "moderate" has gradually diminished in the U.S. since it was 43% in 1992. That is the year Gallup started routinely measuring ideology with the current question. It fell to 39% in 2002 and has been 35% since 2010. At the same time, the country became more politically polarized, with the percentages of Americans calling themselves either "conservative" or "liberal" each increasing.
Gallup measures political ideology by asking Americans to say whether their political views are very conservative, conservative, moderate, liberal, or very liberal. Relatively few Americans identify with either extreme on this scale, although 2 in 10 Republicans self-identify as very conservative -- double the proportion of Democrats calling themselves very liberal.