Once upon a time, a fair number of Americans thought the country might have to abandon democracy. In June 1932, during the worst days of the Depression, the magazine Vanity Fair pleaded: “Appoint a dictator!” Just before Franklin D. Roosevelt took office, the movie “Gabriel Over the White House” depicted how a fictional president solved the economic crisis and brought world peace — by imposing one-man rule. It got good reviews and did well at the box office.

Notwithstanding all the troubles of recent years, we seldom hear explicit anti-democratic sentiments anymore. (One exception is Woody Allen, who wished that President Obama “could be a dictator for a few years because he could do a lot of good things quickly.”) In “Democracy Despite Itself,” Danny Oppenheimer and Mike Edwards explain why: In short, democracy works. Countries that decide things through elections have more freedom and a higher quality of life than those that don’t.

The authors acknowledge that democracies have sometimes failed in their basic functions. But they also cite abundant evidence that nondemocratic regimes are much more likely to restrict speech, ban “unapproved” religions and throw people in jail without due process of law. Contary to myth, dictatorships do not compensate for these failings by making the trains run on time. Oppenheimer and Edwards explain that democracies not only secure more freedom, they tend to deliver better public services.

Oppenheimer, a professor of psychology at Princeton, and Edwards, a political blogger, describe the complex paradox behind this simple conclusion. Success comes from a system that seems perfectly designed to fail. As anybody who has ever worked in a campaign can attest, voters do not always think clearly about politics. In spite of the huge mass of information available, people have only the haziest understanding of what their government does and how it works. Problems such as gerrymandered legislative districts and confusing ballot design make it hard to translate popular opinion into public policy. And democratic politicians can be sleazy, unprincipled or just dumb.

Drawing on research from a variety of fields, the authors ably explain how regular, contested elections enable democracies to transcend these obstacles. When people vote, they become “invested in democracy” and thus are more likely to take part in other forms of civic engagement. Although voters pay only sporadic attention to issues, politicians can never be sure which issues will drive the next election. “This uncertainty, in turn, forces politicians to try to develop policies that benefit all voters and not just themselves.” Elections also serve as a check on misconduct. The authors mention Rep. William Jefferson (D-La.) — whom the FBI caught with bribe money in his freezer — to show that seemingly entrenched incumbents can still lose if they behave badly enough.

’Democracy Despite Itself: Why a System That Shouldn't Work at All Works So Well’ by Danny Oppenheimer and Mike Edwards (MIT Press)

“Democracy Despite Itself” is a useful corrective to the cynicism that pervades so much political commentary. It lays out scholarly findings in engaging, nontechnical language that makes it very suitable for general audiences and introductory classes in political science. Much of the material will be familiar to those who follow politics closely. It comes as no surprise that redistricting can thwart popular will by favoring the dominant party, or that democracies rarely make war against each other. And the tension between free government and flawed human nature has long been a staple of American political thought. In Federalist 51, James Madison famously wrote: “If men were angels, no government would be necessary.”

Sophisticated readers may also notice shortcomings in the authors’ analysis. Oppenheimer and Edwards strain too much in arguing that candidates’ physical appearances can affect election outcomes. They note that the taller candidate won 80 percent of presidential elections between 1900 to 1980. It’s hard to believe that this figure means anything. Aside from the debates of 1960, 1976 and 1980, the voters hardly ever saw candidates side by side, so how could they have known which one was taller? As for the broader claim of a link between looks and getting elected, two words should suffice to create doubt: Chris Christie.

The authors make some factual errors. “In California,” they write, “all tax increases have to pass a popular referendum before they can become law.” In fact, the legislature can raise state taxes by a two-thirds vote. They claim that the controversial Supreme Court case of Bush v. Gore upset many Americans “and probably did reduce voter turnout in subsequent elections.” No, turnout went up. In 2000, 47.1 percent of the voting-age population cast ballots. In 2004, the figure was 51.6 percent, and in 2008, it was 53.3 percent.

The book’s most important limitation is that it gives too little emphasis to the differences between the United States and other democracies. These differences have important consequences, both for good and ill. Take, for instance, our rococo system of federalism, which comprises some 90,000 governments. Americans choose more than half a million elected officials, and in many places they also get to vote directly on legislation through initiatives and referenda. This structure provides unparalleled openings for citizen participation. But it can result in dauntingly long ballots that may discourage some citizens from voting. It also leads to jurisdictional tangles. Some states have legalized medical marijuana, for instance, even though the federal government continues to forbid it.

The authors briefly observe that bicameralism and the separation of powers provide multiple avenues for keeping bad laws from going into effect. True, but this setup has another virtue that the authors neglect: It provides multiple avenues for reasoning about public policy. Both chambers of Congress debate bills, the president confers with advisers on whether to sign them, and the Supreme Court justices often ponder their constitutionality. When it works right, the system is not just democratic but deliberative.

Perhaps such topics would make for a sequel. Meanwhile, this book offers a good account of why democracy works despite itself.

bookworld@washpost.com

John J. Pitney Jr. is a professor of government at Claremont McKenna College and co-author of “American Government and Politics: Deliberation, Democracy, and Citizenship.”

DEMOCRACY DESPITE ITSELF

Why a System That Shouldn’t Work at All Works So Well

By Danny Oppenheimer

and Mike Edwards

MIT. 245 pp. $24.95