Economist Bryan Caplan, whose research feeding into his book The Myth of the Rational Voter led him to wonder why policies in a democracy aren't even worse than they are, finds some answers in the research of Martin Gilens in his new book Affluence and Influence: Economic Inequality and Political Power in America

The key? Evidence seems to indicate that government here listens mostly to the opinions of the rich. Note: not just protects the interests of the rich in a purely pecuniary sense, but skews toward their opinions. Some details from Caplan:

[From Gilens' data], Democracy has a strong tendency to simply supply the policies favored by the rich.  When the poor, the middle class, and the rich disagree, American democracy largely ignores the poor and the middle class.....

And from a libertarian perspective this is just fine, Caplan thinks:

the rich are noticeably less statist on both economic and social policy.  Rich and poor alike favor raising the minimum wage, but the support of the poor is nearly unanimous.  The poor are slightly more in favor of extending unemployment benefits.  They're much more anti-gay.  They're much less opposed to restricting free speech to fight terrorism.  The list goes on.....

Gilens is clearly disturbed, even frightened, by his own results.  On social policy, his findings horrify him as a democrat: Even if the lower classes are intolerant, shouldn't they have equal say?  On economic policy, his findings horrify him as a liberal and a democrat: Isn't it awful when our government fails to adopt the oh-so-wise regulations non-rich Americans support?  

While Gilens is disturbed, Caplan is delighted, and as usual unafraid to offend democratic sensibilities:

Democracies listen to the relatively libertarian rich far more than they listen to the absolutely statist non-rich.  And since I think that statist policy preferences rest on a long list of empirical and normative mistakes, my sincere reaction is to say, "Thank goodness."  Democracy as we know it is bad enough.  Democracy that really listened to all the people would be an authoritarian nightmare.

Reason on Caplan.