Jonathan Chait has a theory about why Trump’s success took him and other pundits by surprise: “The Republican Party turns out to be filled with idiots. Far more of them than anybody expected.” But this idea is singularly unhelpful. It actually helps absolve Trumpkins of responsibility: Idiots are usually not held accountable for their acts.

Thankfully, we have actual data on Trump’s supporters. Far from being idiots, they are people who would normally be considered functioning and successful. Trump’s supporters are better educated and wealthier than the American average.

Rather than characterizing them as losers who are easily fooled, Trump’s supporters—who amount to at least a plurality of the Republican primary electorate—deserve to be looked at in their own terms. Trump’s essential appeal is based on racism. He launched his campaign talking about Mexican “rapists,” and subsequently stirred up xenophobia against many other groups, especially Muslims. His racist pitch succeeded because the Republican Party is overwhelmingly white and has relied heavily on dog-whistle appeals to racism since the early 1960s.

Trump is appealing to the aggrieved privilege of well-to-do white Republicans who feel threatened by America’s changing demographics and challenges to the traditional racial hierarchy in the age of Obama.

Racism is evil, but it is not idiotic from the point of view of racists. White racists see themselves as benefitting from Trump’s proposal to shore up the old racial status quo. Their value system deserves to be challenged, but they aren’t being fooled by Trump. They know what he’s selling and they like it.