As Republicans debated Mitt Romney’s loss in the aftermath of the 2012 presidential election, one factor that came up repeatedly is that Republicans simply are not appealing to the growing demographics in the U.S. Pundits suggested that reaching out to Hispanics or young people might be essential for he party’s future, but a new poll this week show that a growing number of Americans may not be reachable by the GOP.

A Gallup poll released this week shows that more Americans than ever now identify themselves as “liberal.” The survey found that 23% of U.S. adults described their political views as liberal or very liberal in 2013. This represents a small but significant rise from the 18% of Americans who described themselves as liberal two decades ago.

Based on Gallup’s data, it appears that this rise in self-described liberalism in the U.S. can almost entirely be attributed to Democrats. Over the past decade the percentage of Democrats describing themselves as liberal has risen from 32% to 43%, while the percentage of Democrats describing themselves as conservative has fallen from 25% to just 19%.

The poll also found that Republicans have become more conservative in the past decade, though not drastically so. Gallup numbers show that the percentage of Republicans identifying themselves as conservative rose from 66% in 2003 to 70% last year. A corresponding drop in the number of Republicans calling themselves moderate was seen, from 28%in 2003 to 23% last year.

The largest recent shifts in the Gallup poll were seen in Americans who identify as independents. Though the amount of independents calling themselves conservative, moderate, or liberal was stable from 2000 to 2008 (around 46%, 28%, and 22%, respectively), more recent years have seen a significant conservative shift for independents. The new poll shows that 35% of independents now identify as conservative, while only 40% now consider themselves moderate. Independents identifying as liberal has dropped only slightly to 20%.

Rather than long-time independents themselves becoming more conservative, these results could reflect findings released last week that show many former Republicans are now identifying as independents. American self-identification with the Republican party now sits at a new low of 25%.

This increased polarization of American politics could certainly be said to reflect the current state of congress. The lack of action from congress last year and the government shutdown caused by House Republicans sent American congressional approval ratings to their lowest point ever last November. A majority of Americans also now believe the current congress is the worst they’ve seen in their lifetime – a position that is unlikely to change as the country continues to become more polarized.