My fellow Americans, we are one ignorant bunch.

This is particularly true with regard to politics and government, subjects about which the public is a howling void of nescience. To say Americans don't know much about politics and government would be more than just an understatement. It would be like saying a Galapagos tortoise doesn't know much about medieval French literature.

Ilya Somin — a law professor at George Mason University in Fairfax — has written a book on the subject: Democracy and Political Ignorance. In it, he shows that Americans know woefully little about their political system, have known very little for a long time, and are not likely to change in the foreseeable future — because they have a very good reason not to.

For instance: In 1964, only 38 percent of Americans knew the Soviet Union, NATO's principal enemy, was not a member of NATO. In December 1994, the month after Republicans led by Newt Gingrich took control of Congress, 57 percent of Americans had never even heard of him. In 2003, 70 percent of Americans were unaware of the passage of Medicare Part D, "the biggest new government program in several decades."

Fifty-eight percent of Americans cannot name the three branches of government; 70 percent cannot name their state's senators; 72 percent cannot name two or more of the rights guaranteed by the First Amendment.

Before you start cursing, note that Americans have very little incentive to know such basic things, and even less to study more abstruse details such as the content of specific legislation. (In 2009, only a quarter of Americans knew "cap and trade" addressed environmental issues rather than, say, health care or finance.)

This is because the cost, in time and effort, of becoming an informed voter is fairly high. And what do you get for it? Precious little. It isn't polite to say so, but votes usually matter only in the aggregate. Your one vote in, say, a presidential election will have almost no chance of changing the outcome, and therefore roughly zero effect on your life personally. Hence, Somin writes, "For most people, the benefits of devoting more than minimal time and effort to learning about politics are greatly outweighed by the costs."

Granted, there are exceptions — the political junkies who get the same enjoyment from politics that sports junkies get from sports. Sports fans often know a great deal, even though they cannot affect the outcome of the games. (Not even with their lucky hats.) Political fans, Somin writes, likewise "derive enjoyment from rooting for their preferred parties, candidates, ideologies, and interest groups, while deriding the opposition. They … also derive satisfaction from having their pre-existing views validated, and from a sense of affiliation with a group of like-minded people."

So does the team-sports model rescue democracy from the pit of ignorance? Hardly — because partisan activism is, in important ways, even worse than disengagement. Partisans may know more, but their knowledge is often selective. On top of that, they use it in highly biased ways — primarily to reinforce their existing views and reject new information that challenges their cherished dogmas. And they often tune in to news sources (Fox News, MSNBC) that facilitate close-mindedness.

This renders partisans more susceptible to false beliefs that cement their team loyalty: Democrats are more likely than independents to believe "truther" conspiracies alleging that George W. Bush knew in advance about 9/11, and Republicans are more likely than independents to believe "birther" claims that President Barack Obama was born abroad. It also leads partisans to reject truths that do not square with their partisan leanings. In one series of studies, Democrats completely ignored a factual correction in George W. Bush's favor. Republicans were even worse, believing a false claim in Bush's favor even more strongly after seeing it corrected.

Are there any remedies? Perhaps. We could delegate more decision-making to experts. But this only adds a layer to the problem. The experts still would have to be held accountable by elected officials, and ignorant voters "are likely to be poor monitors of elected officials' supervision" of the experts. On the other hand, if the experts are not supervised, then there is no way to ensure they are pursuing the public interest.

We also could limit voting to the knowledgeable. But not only would this be grossly undemocratic, it wouldn't improve matters, for the reasons just described.

Somin suggests two structural remedies. One involves handing over more decision-making to smaller political units — states, or even municipalities — which would allow people to vote with their feet. People who vote with their feet tend to educate themselves first. (Think about how much research you put into buying a house or a car.) And they educate themselves because they know their "vote" — to live on a cul-de-sac, or move to Seattle, or buy a Toyota instead of a Ford — will be the decisive one. When you vote with your feet, the "election" is heavily rigged to produce the outcome you want.

The other structural change? Limit the scope of government. For Somin, the reason is straightforward: A smaller government means deeper knowledge. If the public will learn, say, only 100 things about the executive branch, then it will know a lot more about each agency if there are five agencies rather than 50. There is an "inverse relationship between the size … of government" and "the ability of voters to have sufficient knowledge" to vote intelligently.

For the rest of us, there may be another reason: A smaller government, even in the hands of Those Ignorant Bums on the Other Side, will do less damage than a big one can. When power is decentralized, you can flee to another state if things get too bad in your current one. When Washington is in charge of everything, the cost of voting with your feet gets much, much higher.

Each of these approaches has downsides — though not necessarily the ones you might think. For instance, the cost of moving would seem at first blush to impede "foot voting" by the poor. In fact, Somin notes, "households with an income under $5,000 per year are actually twice as likely to make interstate moves as the population as a whole."

That's just one of the many insights to come out of a book on ignorance that is, perhaps paradoxically, highly informative.