At the National Journal’s ‘The Next America’ blog, Ruy Teixeira and John Halpin have a post explaining “Demographic Fundamentals Remain Critical to 2012 Presidential Outcome.” Teixeira, a TDS co-founding editor, a senior fellow at both The Century Foundation and the Center for American Progress and guest scholar at the Brookings Institution and John Halpin, a senior fellow at the Center for American Progress focusing on political theory, communications, and public-opinion analysis write:

…There is scant historical evidence that the debate will have much of an impact on the eventual outcome of the presidential election…What will matter most are the two fundamentals we outlined in our November 2011 paper, “The Path to 270.” In that report, we argued that the election will boil down to two primary questions. Will the rising electorate of communities of color, the millennial generation, professionals, single women, and seculars that pushed Obama to victory in 2008 be sufficient and mobilized enough to ensure his reelection in 2012? Or will the Republican Party and its presidential nominee capitalize on a struggling economy and greater mobilization from a conservative base that holds the president in deep disdain?

The authors believe these two issues will “remain the central issues of the election” and discuss the impact of three key demographic groups, “minorities, college-educated whites, and noncollege/working-class whites.” They conclude that “Obama should be significantly advantaged in 2012 by demographic change, especially a projected increase in minority voters and decrease in white working-class voters.”
Halpin and Teixeira add further, “…if the president’s minority support holds up in 2012, with the level of Hispanic support being the biggest question mark, he could absorb quite a lot of falloff in his support among white working-class voters and still win the election,” particularly if the president retains the support of white college-educated voters.
The authors then explore the prospects of the presidential candidates with respect to these groups in 2012:

….Based on analysis of the most up-to-date information about eligible voters from the Current Population Survey, the overall minority composition of the electorate increased by 3 points since 2008, while the percentage of white working-class voters declined by an equal amount (see data below preceding map). White college graduates increased also, but only very slightly, about two-tenths of a percentage point.
…These new figures are based on changes in the composition of eligible voters, which may or may not be fully reflected in the composition of actual voters, depending on turnout patterns. Given that minorities’ turnout tends to be relatively low while white college graduates’ turnout is relatively high, the shifts we see in 2012 may still wind up close to our original projection.

Verifying that the president is holding his 2008 support levels from minority voters, the authors note further, “in 11 national polls of Hispanics conducted from December of last year through August 2012, Latino voters have favored Obama over Romney by an average of 43 percentage points, substantially higher than the margin of 36 points they gave the president in 2008.”
Regarding the president’s support among college-educated whites, the authors say that the president is also close to matching or surpassing his 2008 performance with this group. With respect to the pivotal white working-class demographic,

…If the minority and white college-educated vote hold up as well in November as they have in recent polling, Romney needs to generate a huge margin among white working-class voters to have a decent chance of winning–closer to the 30 points congressional Republicans won this group by in 2010 than the 18-point margin received by Sen. John McCain, R-Ariz., in 2008.
In fact, if Obama replicates his 2008 performance among minorities and white college graduates, then Romney would need to carry white working-class voters by double McCain’s margin (36 points) even if the minority vote does not grow at all. And if the minority vote does grow as expected, he would need north of a 40-point margin among the white working class to prevail…Romney has not been remotely close to that level of support among white working-class voters. He’s been averaging around the same margin McCain received in 2008…Romney, to be successful in November’s election, needs to greatly exceed his currently observed upper bound of support among white working class voters.

Teixeira and Halpin caution, however,

…Demographics are important but not determinative of election outcomes. Politics and campaigns matter in putting together viable electoral majorities. A few weeks out, it is certainly possible to see Romney building on his debate performance to turn a surge of conservative activism and white working-class skepticism into a narrow victory should the president’s supporters end up being as apathetic as they were in 2010 and if late-deciding voters break heavily against him. But it is also possible to envision many voters, including some segments of the white working class, turning away from the perceived radicalism of the Republican ticket and agenda and returning the president to office by a few percentage points.

As the authors conclude, “Many difficult challenges lie ahead for both candidates and campaigns to consider. The complex mix of demographics, economics, and ideology makes this already close race even more vigorously contested.”