Our chapter on political parties discusses the idea of party affiliation or identification. The Pew Research Center reports:
As the country enters into the 2012 presidential election cycle, the electorate's partisan affiliations have shifted significantly since Obama won office nearly three years ago. In particular, the Democrats hold a much narrower edge than they did in 2008, particularly when the partisan leanings of independents are taken into account.
Notably, the GOP gains have occurred only among white voters; a two-point Republican edge among whites in 2008 (46% to 44%) has widened to a 13-point lead today (52% to 39%). In sharp contrast, the partisan attachments of black and Hispanic voters have remained consistently Democratic.
While Republican gains in leaned party identification span nearly all subgroups of whites, they are particularly pronounced among the young and poor. A seven-point Democratic advantage among whites younger than age 30 three years ago has turned into an 11-point GOP advantage today. And a 15-point Democratic advantage among whites earning less than $30,000 annually has swung to a slim four-point Republican edge today.
Yet, the Republican Party's growth has been limited in two important ways. First, the steep gains in GOP leaning that helped the party in the 2010 midterms have not continued, as the overall balance of partisan attachments has held steady in the first half of 2011. Second, while more independents say they "lean" toward the Republican Party, the GOP has not gained in actual party affiliation since 2008 -- just 28% of registered voters, in both years, call themselves Republicans. Instead, the growth category continues to be political independents, with a record high 34% of registered voters choosing this label in 2011....
The Millennial generation -- those born after 1980 -- were a topic of much discussion in the 2008 election. These young voters -- the oldest turned 27 that year, and are turning 30 now -- leaned Democratic by roughly two-to-one in the 2008 election, and their commitment to Barack Obama, and relatively high voter turnout, was a substantial factor in the election's outcome.
While these voters remain the most Democratically oriented generation today, the advantage has narrowed substantially since 2008. Currently, 52% of Millennial voters are Democrats or lean to the Democratic Party while 39% are Republicans or lean to the GOP. This 13-point edge is less than half the size of the 32-point edge Democrats held three years ago.
Among voters in other generations, Democrats have lost adherents while Republicans have gained. But these changes have not been as large as those among Millennials.