This is a short but interesting article on the origins of Trump's popularity. It highlights an important point: while economic issues make people more open to outsiders who want to "overturn the system," the root of his support isn't economic at all, but social and cultural. The "liberal elites" who people rail against aren't economic elites, but rather social ones. That is, a lot of the people from whom he is mining his followers are "people who believe they... deserve to be at the center of American life and culture," and who see a culture which instead of treating with respect and deference, often treats them with mockery.
This is a very important point to understand, especially for those who would reduce politics to simple economics. People ultimately value their self-identification very profoundly, often even more than their physical survival. When this is threatened, it can animate extremely violent passions.
Alas, when the self-identification is based on one's identification relative to others
-- as in, "at least we're better than those bastards" -- then the risk of implosion is far higher, since sometimes those bastards end up not playing the role required by your script. The result is inevitably powerful conflict.
via +Jennifer Freeman