No, or at least not very well, according to Bryan Caplan:
Democracy clearly works if you set the bar low enough. Is democracy better than dictatorship? Of course. Does democracy allow most people in the First World to live long, comfortable lives? Sure. But we now hold most of our social institutions to far higher standards. If 90% of women survived childbirth, we wouldn't say "Medicine works." We'd expect doctors to use everything they know - and constantly strive to learn more. And if mothers were dying because doctors stubbornly clung to superstitious treatments, we judge the doctors very harshly indeed.
So what would we conclude if we held democracy to analogous standards? Do democracies use everything we know? Do they constantly strive to learn more? Do they at least avoid acting on sheer superstition? I say the answer is no across the board. When we actually measure voters' policy-relevant beliefs against reasonable proxies for the Truth, voters do poorly. Democracy's defenders often insist that these errors will harmlessly balance out, but the facts of the matter is that voter errors are usually systematic. Voters err alike....
Couldn't we solve this problem with better education? I'd like to believe that, but the facts once again get in the way. "Educating" people out of their policy beliefs is very hard. Why? In large part, because error is, selfishly speaking, free. If a voter is intellectually lazy, what happens to him? The same thing that happens to people like you who voluntarily attend online debates on "Does Democracy Work!" This contrast is easy to see when you offer to bet someone about his policy views: Even passionate ideologues usually decline to back up their extravagant claims with cold hard cash. As I explain in The Myth of the Rational Voter, we shouldn't think of democracy as a market where people buy the policies they like. We should instead think of democracy as a common well where people throw their intellectual garbage, heedless of the fact that we all drink the water.