Have there been other times in history where a party had a demographic crisis?

[All Along The Watchtower]

If trends continue, then Democrats will be in a crisis regarding the white vote.

Well yes and no. If the Dems moved the hard-left yes but also it depends on geography  where more whites are moving back to the cities where its mostly Dem but it does depend on where in these cities that they move to. Like Southern Brooklyn is not as as Dem as the rest of New York City.

Also  more whites are moving away from the evangelical religion which doesn't favor the GOP or whites are identifying as "no religion". More college educated white women are more Dem than the white vote as a whole. McCain and Obama spilt the college educated white women vote in 2008 and Romney won the college educated white women vote in 2012 by 6 points. Also the 18-29 White Demographic did vote for Romney by 7 points in 2012 but the white vote was won by Romney as a whole by 21 points(60-39%) so white youth aren't as loyal to voting GOP as older whites.

No, he won the votes of white women as a whole. And anyway, I think the more important difference re: voting patterns for white women is not level of education, but marital status.