How Donald Trump happened: Racism against Barack Obama. is a good article on the racist aspect of Trump's appeal. Here are two paragraphs I liked:
But this analysis ignores the extent to which Trump reflects specific choices by Republican and conservative elites. From indulging anti-Obama conspiracy theories to attacking him as an enemy of the United States, conservatives chose to nurture resentment and anxiety and distill it into something potent. You can draw a direct line to the rise of Trump from the racial hysteria of talk radio—where figures like Rush Limbaugh, a Trump booster, warned that Obama would turn the world upside down. “The days of [minorities] not having any power are over and they are angry,” said Limbaugh to his audience. “They want to use their power as a means of retribution.”
The good news is that movements like Trump’s tend to fade away. The bad news is that, even in defeat, they are influential. One antecedent to Trump—Alabama Gov. George Wallace—never won a national party nomination. But he had massive impact on the direction of national politics, giving Richard Nixon raw materials for his “Southern Strategy” of racial resentment that would shape and define American politics for the next four decades.