How many Americans are atheists?

A headline from Slate caught my eye this week: “” title=”article I wrote” target=”_blank”>article I wrote for the LA Daily News:

Depending on the definition, researchers estimate atheists make up 3 to 10 percent of the U.S. population.

Most likely to be educated and men and ranging from liberals to libertarians, experts say, atheists’ chief interest shifts from promoting science to fighting religious influence on politics, depending on the cultural climate.

Part of the reason that researchers have struggled to peg the atheist population is that there is no clear definition of who is an atheist. It might not be as vexing a question as