Why the white working class votes against itself

This is one of the biggest mysteries I know of -- why people vote against their own self-interest.

https://www.washingtonpost.com/opinions/why-the-white-working-class-votes-against-itself/2016/12/22/3aa65c04-c88b-11e6-8bee-54e800ef2a63_story.html?wpisrc=nl_opinions&wpmm=1

From the site:

Here’s the problem. These Democratic policies probably would help the white working class. But the white working class doesn’t seem to buy that they’re the ones who’d really benefit.