How much of the racial voting differences are simply due to age and income?

[mileslunn]

Age and income are part of it, but even excluding those, I think there is still a racial gap.  Lets remember amongst whites 18-29 Romney won this 54-45% while overall it was 60-38%.  Now I wouldn't be surprised if Obama would have won the electoral vote for whites 18-29 as I suspect he would have narrowly carried that group in most Northern states and more solidy in the Pacific Northwest and New England states, while got clobbered amongst whites 18-29 in the South.  I think if you take the South out of the picture where racial divisions are still quite strong, some of the difference could be simply where minorities live.  In the large urban centres, I suspect Obama won the white vote, whereas in rural areas that went GOP the minority population is quite small and generally people who live in smaller communities tend to be more conservative than those living in large urban centres.  Still the gap does exists even when you include other factors.

[mileslunn]

You have it backwards. The age gap is because of race. Not vice versa.

Partially true although amongst whites 18-29 it was a lot closer than amongst older whites never mind I suspect Romney's huge majority amongst whites 18-29 in the South probably skewed the results somewhat too.  Lets remember in the New England states and Pacific Northwest or even Upper Midwest which are fairly white, Obama did much better amongst younger voters than older ones.  Off course this is not unique to the US.  In Europe, Canada, Australia, and New Zealand, parties on the left tend to do better amongst younger voters than older voters.  In the 2005 British election, the Conservatives came in third at under 20% amongst the under 30 crowd while won the over 50 crowd.  Likewise here in Canada, the NDP (left wing party) won the under 30 vote while the Conservatives got close to 50% amongst the over 65 crowd.  People tend to be more idealistic when young while get pragmatic and also more resistent to change as they get older.  Also the marriage gap may be a reason too since amongst married men vs. married women, there wasn't much difference, whereas amongst unmarried women; Obama did significantly better than unmarried men although he won both and those groups would be highest amongst the young and the old.

[mileslunn]

I would say race is probably the largest factor, although where one lives and age are also factors, not as much as race but more so than income.  After all those 18-29 including those who are making over $100,000 vote more heavily Democrat than the 65+ group making under $30,000.  There is also the location factor as many of the most solid blue states happen to be amongst the wealthier states whereas the poorest states are almost all red states.  There is also the education factor as people with higher incomes are more likely to favour the GOP, but people with higher levels of education are more likely to favour the Democrats and as a general rule people with higher levels of education tend to make more money.