47% of Americans identified as Democrats or said they were independents who leaned Democratic in 2012, compared with 42% who identified as or leaned Republican, according to Gallup. That re-establishes a Democratic edge in party affiliation after the two parties were essentially tied in 2010 and 2011.
The estimates are based on an aggregate of all 2012 Gallup … polls, … more than 20,000 interviews…. [Since 1991], Democrats have usually held an advantage, including the high margin of 12 points in 2008, the year President Obama was elected. Republicans have held an advantage in only one year — 1991, when President George H.W. Bush enjoyed record-high approval ratings after the Persian Gulf War.
… The new Democratic advantage is mostly due to an increased proportion of Democratic-leaning independents and a decreased proportion of Republican-leaning independents.