"AMERICA IS A CHRISTIAN NATION"

Not so much, really.   For one, Americans are surprisingly ignorant about religion according to this Pew survey released on 9/28/2010:

Atheists and agnostics, Jews and Mormons are among the highest-scoring groups on a new survey of religious knowledge, outperforming evangelical Protestants, mainline Protestants and Catholics on questions about the core teachings, history and leading figures of major world religions.

For some reason, though, (h/t Atrios) Americans LIE about how often they attend church services:

Walking Santa, Talking Christ
Why do Americans claim to be more religious than they are?
By Shankar VedantamPosted Wednesday, Dec. 22, 2010, at 5:13 PM ET
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Americans are hardly more religious than people living in other industrialized countries. Yet they consistently—and more or less uniquely—want others to believe they are more religious than they really are.

In a more recent study, Hadaway estimated that if the number of Americans who told Gallup pollsters that they attended church in the last week were accurate, about 118 million Americans would be at houses of worship each week. By calculating the number of congregations (including non-Christian congregations) and their average attendance, Hadaway estimated that in reality about 21 percent of Americans attended religious services weekly—exactly half the number who told pollsters they did.

Finally, in a brand new paper, Philip Brenner at the University of Michigan's Institute for Social Research compared self-reported attendance at religious services with "time-use" interviews in the United States, Canada, the Netherlands, Germany, France, Norway, Finland, Slovenia, Italy, Spain, Austria, Ireland, and Great Britain. Brenner looked at nearly 500 studies over four decades, involving nearly a million respondents.

Brenner found that the United States and Canada were outliers—not in religious attendance, but in overreporting religious attendance. Americans attended services about as often as Italians and Slovenians and slightly more than Brits and Germans. The significant difference between the two North American countries and other industrialized nations was the enormous gap between poll responses and time-use studies in those two countries.