“The flaw in the pluralist heaven is that the heavenly chorus sings with a strong upper-class accent,” wrote E.E. Schattschneider in a 1960 critique of the “pluralist” political science orthodoxy of the day. Pluralism viewed American politics and policy as the product of a free-wheeling competition among interest groups seeking to influence the government. In Cold War America, this theory also served the ideological pretense holding that no “power elite” or “ruling class” rigged the game of American democracy in its favor.

The Unheavenly Chorus: Unequal Political Voice and the Broken Promise of American Democracy, by Kay Lehman Schlozman, Sidney Verba and Henry E. Brady, takes its inspiration and title from Schattschneider. But where Schattschneider observed that “American politics is [not] a meaningless stalemate about which no one can do anything,” Schlozman, Verba and Brady—writing in the era of Occupy Wall Street—aren’t so sure.

Schlozman, Verba and Brady are not political radicals. They are three of the most published and respected mainstream political scientists who have studied American government, public opinion, and citizen participation since the 1960s. Yet their multifaceted study demonstrates over and over the impact of social class and inequality on government policy, and on the system of political representation itself. In fact, they explicitly tie increased economic inequality and the decline of labor unions over the last several decades to the political system’s democratic deficit.

The Unheavenly Chorus addresses individual political participation and the nature, composition, and activities of interest groups in the American system. Using survey data, data on campaign contributions, and their own analysis of Washington-based lobbying groups over three decades, they systematically answer one question after another.

Do successive generations of Americans gain greater access to American political institutions? No, the authors show, political inequality is transmitted and reinforced across generations. Do organized interest groups help ordinary Americans get their voices heard? With the exception of (shrinking) labor unions, the authors conclude, the interest system provides almost no real means for ordinary Americans to have their voices heard in Washington. Can the Internet act as a “leveler,” helping ordinary citizens to organize against moneyed interests? No, again. The authors show how business interests and trade associations vastly outmaneuver ordinary people, even in the realms of Facebook and Twitter.

Their research even calls into question the notion of what we think an “interest group” is. The vast majority of lobbying organizations in Washington aren’t membership groups like the Sierra Club or the National Rifle Association, but institutions like corporations, state governments, universities, and hospitals. This reality reinforces the domination of business interests, they write, whose activity may vary, but “in no case is it outweighed by the activity of either organizations representing the less privileged or public interest groups.”

After hundreds of pages that reinforce the class-skewed nature of American democracy, the authors feel compelled to answer, in the name of one of book’s chapters, “What, if Anything, Is To Be Done?” Here, they consider a number of reforms (improved political education, campaign finance reform, universal voter registration, and the like) while noting that addressing “inequalities of income and education is not a matter of mere institutional tinkering but would constitute a political and social revolution requiring a level of patience and a commitment of resources that have not been characteristic of American policy.” Later, they comment, “the changes that would have the greatest impact are the least likely to happen.” They’re left hoping that some combination of smaller-scale reforms will, at least, take the edge off the most extreme inequalities in the system.

One final point: for a nearly 700-page work of social science, The Unheavenly Chorus is fairly accessible and readable. Its chapter summaries are very useful for those who don’t have the time to wade through every page. It presents most of its statistics in easy-to-understand graphics like pie charts and line graphs. And any political science tome whose preface riffs on The Onion is worth a look.