One golden standard of successful democracy is whether its political decisions and institutions adequately reflect the will of the people. But what exactly is this will of the people? Is it the sum of constituent preferences or is it something beyond that?
Habermas believes that genuine democracy is rooted in the principles of communicative rationality. Though I think it is very much an open question whether rational argument can ever take place in a democracy—especially one like ours that seems very far from what Habermas envisions—I do hold out some hope that we may eventually be able to design a public sphere in which reason regularly wins out over power and propaganda.