PRINCETON, NJ -- Thus far in 2009, 40% of Americans interviewed in national Gallup Poll surveys describe their political views as conservative, 35% as moderate, and 21% as liberal. This represents a slight increase for conservatism in the U.S. since 2008, returning it to a level last seen in 2004. The 21% calling themselves liberal is in line with findings throughout this decade, but is up from the 1990s.

These annual figures are based on multiple national Gallup surveys conducted each year, in some cases encompassing more than 40,000 interviews. The 2009 data are based on 10 separate surveys conducted from January through May. Thus, the margins of error around each year's figures are quite small, and changes of only two percentage points are statistically significant.

To measure political ideology, Gallup asks Americans to say whether their political views are very conservative, conservative, moderate, liberal, or very liberal. As has been the case each year since 1992, very few Americans define themselves at the extremes of the political spectrum. Just 9% call themselves "very conservative" and 5% "very liberal." The vast majority of self-described liberals and conservatives identify with the unmodified form of their chosen label.

Party-Based Ideology

There is an important distinction in the respective ideological compositions of the Republican and Democratic Parties. While a solid majority of Republicans are on the same page -- 73% call themselves conservative -- Democrats are more of a mixture. The major division among Democrats is between self-defined moderates (40%) and liberals (38%). However, an additional 22% of Democrats consider themselves conservative, much higher than the 3% of Republicans identifying as liberal.

True to their nonpartisan tendencies, close to half of political independents -- 45% -- describe their political views as "moderate." Among the rest, the balance of views is tilted more heavily to the right than to the left: 34% are conservative, while 20% are liberal.

Gallup trends show a slight increase since 2008 in the percentages of all three party groups calling themselves "conservative," which accounts for the three percentage-point increase among the public at large.

Thus far in 2009, Gallup has found an average of 36% of Americans considering themselves Democratic, 28% Republican, and 37% independent. When independents are pressed to say which party they lean toward, 51% of Americans identify as Democrats, 39% as Republicans, and only 9% as pure independents.

Ideological tendencies by leaned party affiliation are very similar to those of straight partisan groups. However, it is worth noting the views of pure independents -- a group usually too small to analyze in individual surveys but potentially important in deciding elections. Exactly half of pure independents describe their views as moderate, 30% say they are conservative, and 17% liberal.

As reported last week on Gallup.com, women are more likely than men to be Democratic in their political orientation. Along the same lines, women are more likely than men to be ideologically "moderate" and "liberal," and less likely to be "conservative."

Still, conservatism outweighs liberalism among both genders.

The pattern is strikingly different on the basis of age, and this could have important political implications in the years ahead. Whereas middle-aged and older Americans lean conservative (vs. liberal) in their politics by at least 2 to 1, adults aged 18 to 29 are just as likely to say their political views are liberal (31%) as to say they are conservative (30%).

Future Gallup analysis will look at the changes in the political ideology of different age cohorts over time, to see whether young adults in the past have started out more liberal than they wound up in their later years.

Bottom Line

Although the terms may mean different things to different people, Americans readily peg themselves, politically, into one of five categories along the conservative-to-liberal spectrum. At present, large minorities describe their views as either moderate or conservative -- with conservatives the larger group -- whereas only about one in five consider themselves liberal.

While these figures have shown little change over the past decade, the nation appears to be slightly more polarized than it was in the early 1990s. Compared with the 1992-1994 period, the percentage of moderates has declined from 42% to 35%, while the percentages of conservatives and liberals are up slightly -- from 38% to 40% for conservatives and a larger 17% to 21% movement for liberals.

Survey Methods

Results are based on aggregated Gallup Poll surveys of approximately 1,000 national adults, aged 18 and older, interviewed by telephone. Sample sizes for the annual compilations range from approximately 10,000 to approximately 40,000. For these results, one can say with 95% confidence that the maximum margin of sampling error is ±1 percentage point.

In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.