The only demographic that votes majority GOP is white males, especially the older ones. They are afraid of losing their power. I don't understand the fear.
There is some truth to this, although it could be related to the more basic idea that people tend to vote their pocketbook. What I've noticed is that a lot of people are worried they could lose their livelihood or face a future where their lives (and the lives of their children) are relatively worse than that of their parents and grandparents.
I'm not sure if it's so much about power, although it could be indirectly related to that. It's more about economics, at least as far as what I can observe.
The Democrats are (or were) supposedly the party of the working man, and as such, their message has traditionally been that working people would be better off under Democratic policies. If most people (including white males) believed that Democrats really had the interests of working people at heart, then they would get the votes - and they could siphon off millions of white male votes away from the GOP. For whatever reason, white working people somehow believe that they'd get a better deal from the GOP, and the Democrats need to ask themselves why they think that.