Not exactly. That’s PART of the issue, but race and sex are significant factors too. For instance, Romney might have carried the white youth vote by a hair (and I’m not even sure about that) but the margins weren’t even close to what they were with their white elders. And blacks of every age group are much more likely to vote left than their white age-mates.
So, yes, the issue is demographics, but in it’s totality — not just age.
Racial identity-—not religious affiliation, age, or economic status seems to be the biggest factor in determining voting behavior....when you consider that BHO won about 95% of the black vote, and about 75% of the Hispanic and Asian vote, while Romney won about 60% of the white vote. If you could somehow factor out gays, Jews, and union members from the white vote, Romney won about 75% of the white vote. Tell me your race, and I’ll tell you how you vote. Voting seems to be mostly along racial lines these days.