MacWilliams studies authoritarianism — not actual dictators, but rather a psychological profile of individual voters that is characterized by a desire for order and a fear of outsiders. People who score high in authoritarianism, when they feel threatened, look for strong leaders who promise to take whatever action necessary to protect them from outsiders and prevent the changes they fear.
So MacWilliams naturally wondered if authoritarianism might correlate with support for Trump.
He polled a large sample of likely voters, looking for correlations between support for Trump and views that align with authoritarianism. What he found was astonishing: Not only did authoritarianism correlate, but it seemed to predict support for Trump more reliably than virtually any other indicator. He later repeated the same poll in South Carolina, shortly before the primary there, and found the same results, which he published in Vox: