Digby links to an article in the National Journal about the composition of the current Democratic Party and Obama's chances 2012.
I haven't decided on what I think about the piece but it's a good start for discussions. Note, for example, these snippets:
Slightly off the topic, it seems to me that articles like this are never written about the negatives of the Republican Party when it does poorly.
From every angle, the exit-poll results reveal a new color line: a consistent chasm between the attitudes of whites and minorities. The gap begins with preferences in the election.
Meanwhile, Republicans, with their 60 percent showing, notched the party's best congressional result among white voters in the history of modern polling. Media exit polls conducted by Edison Research and its predecessors have been tracking congressional elections for about three decades. In no previous exit poll had Republicans reached 60 percent of the white vote in House races. The University of Michigan's National Election Studies, a biennial pre- and postelection poll, is another source of data on voting behavior dating to 1948. Republicans had never reached 60 percent of the congressional vote among whites in any NES survey. Only in the NES surveys had Democrats reached that 60 percent congressional support level among white voters: in their 1974 post-Watergate landslide and in Lyndon Johnson's 1964 rout of Barry Goldwater.
Democrats have been losing support among blue-collar white voters since the 1960s, but in this election, they hit one of their lowest points ever. In House campaigns, the exit poll found, noncollege whites preferred Republicans by nearly 2-to-1 with virtually no gender gap: White working-class women—the so-called waitress moms—gave Republicans almost exactly as many of their votes as blue-collar men did.
White-collar men and women also parted ways much more significantly than their blue-collar counterparts did. College-educated white men backed Republican House candidates and registered negative views of Obama's job performance as overwhelmingly as blue-collar whites did. College-educated white women, though not immune to these trends, displayed more resistance. Although traditionally the most liberal portion of the white electorate, even these women cooled toward Democrats last year. In contrast to the majority support they provided Obama in 2008, they voted 55 percent to 43 percent for Republicans in 2010 House races. In the exit poll, most of them agreed that government was trying to do too much, and a slim majority of them said they wanted Congress to repeal the health care law.