If this pattern continues, 2011 will be the third straight year that conservatives significantly outnumber moderates -- the next largest ideological bloc. Liberalism has been holding steady for the past six years, averaging either 21% or 22%, although notably higher than the 17% average seen in Gallup polling during the early to middle '90s.

Longer term, the Gallup ideology trend, dating from 1992, documents increased political polarization in the country. The percentage of moderates has fallen to the mid-30s from the low 40s, while the combined percentage either liberal or conservative is now 62%, up from 53%.