This staff post was first published on November 7, 2012.
For insightful analysis of elections, it’s always good to check in with the National Journal‘s ace Ronald Brownstein, who observes today:

President Obama won a second term by marrying the new Democratic coalition with just enough of the old to overcome enduring economic disenchantment and a cavernous racial divide.
In many places, particularly across the Sun Belt, Obama mobilized the Democrats’ new “coalition of the ascendant,” winning enough support among young people, minorities and college-educated whites, especially women, to overcome very weak numbers among blue-collar whites and college-educated men. But in the upper Midwest, where there are not enough of those voters to win, Obama attracted just enough working-class whites to hold the critical battlegrounds of Wisconsin, Iowa, and above all Ohio against Mitt Romney’s forceful challenge.

Brownstein notes that with Obama’s victory, Democrats have matched the GOP record of winning the popular vote in 4 of 5 elections. he adds that “Obama also held all 18 “blue wall” states that have voted Democratic in each election since 1992. By doing so he set a new milestone: that is the most states Democrats have won that often since the formation of the modern party system in 1828.”
Brownstein explains that Obama adroitly rode the “tailwind” of demographic transformation, as people of color now cast 28 percent of the ballots in a presidential election, and Obama received 80 percent of their votes, “including not only more than nine in 10 African-Americans, but also about seven in 10 Hispanics, and about three in four Asians.”
“In the key Midwestern battlegrounds with much smaller minority populations,” adds Brownstein, “the president engineered a different formula for victory…Obama exceeded his national performance among white voters by just enough to repel Romney’s challenge” by successfully characterizing Romney as “an insensitive plutocrat.” yet, nationwide, “Obama captured a smaller share of the white vote than John Kerry did when he lost in 2004.”
In that way, the election offered warning signs to each party.
It’s a warning sign for Democrats, says Brownstein, but a disaster for Republicans: “By winning nearly three-fifths of whites, Romney matched the best performance among white voters ever for a Republican challenger–and yet he lost decisively in the Electoral College.” Brownstein adds,

…By failing to compete more effectively for the growing minority population, Republicans have lowered their ceiling in presidential politics, and left their nominees trying to thread a needle to reach a majority either in the popular or Electoral College vote.

Brownstein concludes of Obama’s re-election,

…His victory underscored the enduring polarization along ideological, regional, and racial lines: For instance, while about three-fifths of Hispanics and three-fourths of African-Americans who voted said they wanted his health care law maintained or even expanded, nearly three-fifths of whites said they wanted it repealed…How Washington makes progress on the biggest challenges we face while the nation is both deeply and closely divided is the largest question looming after Obama’s historic victory.

There is no question that President Obama and the Democrats have won an impressive mandate. The challenge ahead is to increase the comfort level of white working class voters as a permanent constituency in the new Democratic coalition.