To foreigners, there is something downright peculiar about the deep reverence Americans show for their flag, a reverence that has burst into the realm of politics in the battle over a proposed constitutional amendment to ban flag burning.

"At the foreigner's first glance, the steamy and conflicting emotions of the American public and the tortured posturing of politicians over the issue of banning the burning of the Stars and Stripes seems ludicrously exaggerated," Xan Smiley wrote in Sunday's London Daily Telegraph. "Worse things have been done to the Union {Jack} flag, with barely a whimper of outrage in the Commons."

But as Smiley conceded, and as historians and students of popular culture testify, there really is something special about America's relationship to its flag, which is why conservative politicians believe they have much to gain from making an issue of of flag "desecration."

That very term -- rooted in the word "sacred" -- endows a thoroughly secular object with near-religious meaning, and America's flag, say the historians, carries cultural and emotional burdens that in most societies are spread among various other symbols and rituals. As a country that is not based on a single ethnic group or race or religion, the United States has to anchor its unity in ideas -- and in humanly-created symbols.

"America invented itself in a way that England, France and Russia did not," said the Rev. Richard John Neuhaus, the author of "The Naked Public Square," a book that traces a decline in national consensus around ethical and religious values. "The flag is coterminous with our national existence. Most other nations had flags, plural."

The Stars and Stripes were decreed by the Second Continental Congress in June 1777, less than a year after the Declaration of Independence, and Page Smith, a historian at the University of California at Santa Cruz, said the notion that the flag has been there from the beginning is so deeply imbedded in popular consciousness that it even became part of a Dean Martin routine. In it, George Washington scolds a beleaguered Betsy Ross with the words: "Hurry up, because the country starts tomorrow."

"What other national symbol is there, really?" asked Peter Marzio, a historian who directs the Museum of Fine Arts, Houston. "You don't have royalty. You never had an established church in the European sense. So the flag is almost isolated. There's nothing else. It has no competition."

And in a nation that has so often finds itself divided over fundamental values, said Amitai Etzioni, a sociologist at George Washington University, the flag has another virtue: "Nothing's written on it. So we can all project on it what we want. Some people project free speech."

That, of course, goes to the heart of the debate over the constitutional amendment to ban flag burning. "The flag has played a dual role," said Benjamin Barber, a political science professor at Rutgers University. "It's the symbol of the Constitution and the Bill of Rights and tolerance and diversity, but it has always been a symbol of the American nation. Those who want to ban flag burning are playing to the symbol of the nation. But as they do so, they're rubbing against the very symbols of tolerance and diversity that the flag stands for."

What strikes Alan Brinkley, a historian at the City University of New York Graduate School, is how much more important the flag became in the 20th century -- partly in reaction against the very diversity that some see the flag standing for.

Brinkley says that the flag became a key element in popular campaigns to "Americanize" the enormous waves of immigrants who arrived in America between 1870 and 1920. The flag was also used as a symbol in the drive against radicals after World War I, since many saw radicalism as an "un-American" import, brought by the new immigrant groups. Those campaigns led to the adoption of the Star Spangled Banner as the national anthem in 1931.

The flag's identification with opposition to radicalism -- and with the prosecution of the Cold War after World War II -- made it all the more attractive a target for opponents of the Vietnam War. Flag burnings, Brinkley said, became a key part of New Left "iconography," and so opposition to flag burning became increasingly important to the New Left's opponents.

Neuhaus recalled that at least one person on the Left who understood the power of the flag as symbol was the late Socialist leader Norman Thomas. He suggested not mass flag burnings, but mass flag washings. "He said our purpose should be not to burn the flag but to cleanse it," Neuhaus said.

Some religious traditionalists like Neuhaus are uncomfortable with the sacralization of a secular object.

"The use of the language of holiness with respect to a national symbol raises serious questions for Christians, Jews, Moslems and others who have a keen awareness of the dangers of idolatry," he said. "It's a kind of ersatz sanctification of a national symbol."

"You can burn a cross and no one will put you in jail," said Robert Bellah, a sociologist at UC Berkeley. "You can burn a Star of David and no one will put you in jail." To then ban flag burning, he said, seems odd. "In a nation where we claim to believe that God is higher than the nation, that's bizarre," he said.