This is the conclusion of two American scholars, who say all American civic life is deeply rooted in the Christianity of America's original European settlers, many of whom fled the intolerance of the state-sponsored Church of England to practice their own religions.
In fact, Dewey Wallace, a professor of religion at George Washington University in Washington, notes that Europe historically has had state religions. Wallace says this practice has led many Europeans to resist worship. But in America, he says, religion is a matter of choice and therefore embraced more freely.
"They have state support of religion in much of Europe, but the people are not themselves personally religious to the degree that people in the United States are," Wallace said. "This has to do with the fact that it's a state-sponsored religion, whereas in this country religion is something that devolves from the people outside of state support. We have a very different tradition, which is the separation of church and state and religious volunteerism."
Wallace said that another reason Americans remain more religious than residents of other industrialized Western countries is also directly related to Europe's history of state-sponsored religion. Even today, he said, countries such as Britain, Denmark, and Norway directly fund state churches.
That denies congregations what Wallace calls "ownership" -- engagement in the very existence of their churches, and can contribute to religious apathy. Not so in the United States.
"Americans' religious institutions are their own. They weren't imposed upon them. They were developed from the grass roots, and so people have a sense of ownership [of their religions]," Wallace said. "For example, most [American] Protestants choose their own ministers, run their own [church] affairs, raise their own money. If the lay people don't raise the money, there's no church. It's that sense of ownership that people have in this country. It's precisely because we have separation of church and state, and no state support for [religion] that religion flourishes so much."
David Adams, a Lutheran theologian at the Concordia Seminary in St. Louis, said that roughly half of Americans worship regularly -- not necessarily every week, but frequently enough to consider themselves observant. By contrast, he points to Britain, where he said the same can be said for only about 2 percent of the population.
Historically, Adams told RFE/RL, Americans have been more religiously active, and this shows in the country's civic life, even in the way Americans vote. In fact, he said, the country's Protestant denominations tend to promote religious influence on public life.
"Both conservative and more liberal Protestantism see the shaping of the society as part of the role of the church," Adams said. "This goes all the way back in American history to the [U.S.] Civil War. The strongest elements of the abolitionist movement that led up to the Civil War were the churches. There have been others, as well. The civil rights movement [of the 1950s and '60s] was largely driven by the churches."
Religion is not an issue in America's current presidential campaign. But Adams said that many American voters expect their leader to be religiously observant. But he said that does not mean it would be impossible for an agnostic or even an atheist to be elected president.
For example, he said President George W. Bush's Republican Party probably would never nominate an agnostic for the presidency, as long as its membership continues to include a large number of conservative Christians. But he said such a nomination is conceivable for the rival Democratic Party, whose members tend to be less driven by religion.
Could such a candidate win the White House? Adams said it depends on the candidate and the issues facing the country.
"It would really probably depend more on how the candidate handled himself when the issue came up -- whether he seemed to be open, caring, sympathetic to all sides," Adams said. "And secondly, where he stood on other issues that were hot at the moment. I don't think [his religious beliefs] would be a decisive factor."
In other words, Adams said, the choice in this hypothetical election is much the same as that the evenly divided American electorate faces today. Virtually no Democrats are expected to vote for Bush in the 2 November presidential poll, and virtually no Republicans are expected to vote for Bush's rival, Senator John Kerry.