Can you name the three branches of American government -- legislative, executive and judicial? If so, you are among the one-half of Americans who know this very basic fact about the U.S. government and Constitution.

The Intercollegiate Studies Institute (ISI), which earlier has conducted in-depth studies of what American college students know, and don't know, about civics, now reports equally depressing facts about grown-ups. It appears that adults, too, lack the civic knowledge they need to be informed citizens and intelligent voters.

ISI administered a very basic test on American history, government and economics to 2,500 Americans age 25 and older. The multiple-choice test asked citizens to identify terms that everybody should know, such as the New Deal, the Electoral College, Sputnik, "I Have a Dream" and progressive tax.

The 2,500 adults scored an average of 49 percent -- that means they get a pitiful F. Those who had received a bachelor's degree averaged 57 percent on the test, compared to 44 percent for those with only a high school diploma. Worse still, 164 adults who had held elected office also scored an average of 44 percent.

Almost 40 percent of respondents said they thought the president (rather than Congress) has the power to declare war. Only 50 percent knew that Congress shares authority with the president over U.S. foreign policy. And almost one in four thought Congress shares authority over U.S. foreign policy with the United Nations.

Americans who lack knowledge of our country's history, Constitution and institutions really have no frame of reference to judge current politics and policies. Federal law requires public schools to teach about the U.S. Constitution on Constitution Day, Sept. 17, but it looks like American adults need those lessons, too.

The 2006 National Assessment of Education Progress (NAEP) Civics Test revealed that the majority of eighth-graders could not explain the purpose of the Declaration of Independence. No wonder young voters are not shocked at those who talk about "interdependence," globalism, and becoming "citizens of the world."

It's not just that American citizens lack knowledge of historical and constitutional facts about our country, but they also show a declining appreciation of who we are. A survey by Harris Interactive reported that 84 percent of respondents believe we have a unique American identity, but 64 percent believe this identity is weakening, and 24 percent believe we are already so divided that a common national identity is impossible.

Political correctness in colleges and public schools over the last decade has gone a long way toward replacing patriotism with the trendy dicta of multiculturalism, diversity and global citizenship. Are we losing our identity as Americans?

To address this question, the Bradley Foundation has started a national conversation on America's National Identity called "E Pluribus Unum." The question is: Is America still "from many, one" ("indivisible," as our Pledge of Allegiance affirms), or are we fast becoming "from one, many"?

A review of history textbooks used in public schools today reveals a big source of the problem. Textbooks now emphasize America's faults and mistakes rather than our incredible achievements.

History textbooks should tell the exciting story that the United States has produced nearly all the world's greatest inventions and that these inventions have produced living standards that are the envy of the world. This exciting narrative is not based on Americans being smarter than other nationalities, or our having more natural resources than other countries, but on the wisdom of the Founding Fathers, who gave us the superior political and economic system enshrined in our Constitution.

We should celebrate and honor our nation's heroes, starting with George Washington. Federal law clearly specifies that the name of the "legal public holiday" on the third Monday in February is "Washington's Birthday."

Americans should refuse to buy the calendars that wrongly label this February holiday as "Presidents Day." This calendar mischief is very offensive because there are quite a few presidents who are not worthy of a special "day."

Maintaining our national identity depends on keeping our Constitution safe from the supremacist judges who want to change it to comport with what they call "emerging standards." Our national identity depends on keeping English as our official, national language so we don't suffer the conflicts endured by nations with competing languages.

America was founded by men who shared a common inheritance in the British rule of law developed over centuries (beginning with the Magna Carta), the Christian religion and the English language. They also shared the belief later expressed by Alexis de Tocqueville that America is "quite exceptional" and by Ronald Reagan that America is "the shining city on the hill."