As the 2008 conventions approach, the Democratic Party’s advantage in party identification remains as large as it has been over the past two decades, and the Democratic Party’s image remains substantially more positive than the GOP’s. The Democrats have a 13-point lead in party affiliation (51% vs. 38%) among registered voters, when independents who “lean” to either party are included. Four years ago, the Democrats held only a slim 47% to 44% lead by this same measure.

This report provides a detailed breakdown of party identification trends from 2004 to 2008, along with demographic profiles of Democrats and Republicans. These analyses are based on summary data of all registered voters interviewed by the Pew Research Center in each year. For 2008 (January-August), the base is 17,543 registered voters for a margin of error of plus-or-minus 1%.

Also included are breakdowns of opinions of Republicans, Democrats and independents on major issues from recent Pew surveys, and analyses on a number of measures from Pew’s 2007 Political Values Study through a partisan prism.

Read the full report.