I see neither well-functioning democracies nor democracies highjacked by special interests. Instead, I see democracies that fall short because voters get the foolish policies they ask for. (p 22)I'm not far into the book yet. It seems a key foundation for his analysis is the idea that voters have preferences about beliefs concerning how the world works. Voters mostly seem to take their personal preferences about these beliefs as given and they generally devote little attention to checking those beliefs against reality. In particular, voters beliefs about economic issues are taken by Caplan to be systematically wrong.
Biased beliefs about economics make democaracy worse at what it does most. (p 21)