New data indicate that the Democratic Party is the party of youth, secularism and diversity...

... while the GOP represents the older generation, especially the blue collar oldies.  Read about it here.

In a nutshell:

"Barack Obama’s presidency appears to have profoundly shifted the voter coalitions behind the two major parties, with older and blue-collar whites moving to the Republicans as college graduates and secular voters have accelerated their shift to the Democrats."

Find the whole Pew Foundation study here.

"The fundamental demographic changes taking place in the country – an aging population, growing racial and ethnic diversity and rising levels of education – have reshaped both party coalitions. But these changes, coupled with patterns of partisan affiliation among demographic groups, have influenced the composition of the two parties in different ways. The Democratic Party is becoming less white, less religious and better-educated at a faster rate than the country as a whole, while aging at a slower rate. Within the GOP the pattern is the reverse: Republican voters are becoming more diverse, better-educated and less religious at a slower rate than the country generally, while the age profile of the GOP is growing older more quickly than that of the country."