The composition of likely voters appears to have become more politically polarized, with the proportions of conservatives and liberals expanding since 1994 at moderates’ expense. However, Gallup’s initial 2010 estimate of likely voters shows a particularly sharp jump in the percentage of conservatives, from 42% in 2006 to 54% today, and a decline in the percentage of moderates, from 37% to 27%.

This ideological change is accompanied by a concomitant shift toward Republicans, who have a nine-percentage-point advantage over Democrats in the likely voter pool: 39% vs. 30% at this point, one month before the elections. This exceeds the GOP’s five- and six-point advantages in Gallup’s final pre-election polls in 1994 and 2002, respectively, and is a reversal from 1998 and 2006, when Democrats slightly outnumbered Republicans.