On Tuesday, an atheist advocacy group heralded its participation in conservative super-gathering CPAC in March, only to be booted hours later after howls from conservative Christians and a taunt from the atheist group's president that "the Christian right should be threatened by us."

The episode was a perhaps overly dramatic episode over a conference booth, but it reignited continuing tensions among conservatives over how to court a growing cohort of non-religious Americans and navigate changing views on social issues.

"I'm really disappointed, but I'm not at all surprised," said David Silverman, president of American Atheists. "We were going to CPAC specifically to combat the notion that one must be Christian in order to be conservative. We wanted to bring that to the forefront."

But conference organizers said that while they were open to the group, Silverman's comments went too far. CPAC spokesperson Meghan Snyder said Silverman's group "misrepresented itself about their willingness to engage in positive dialogue and work together to promote limited government," in an e-mail to The Washington Post.

Snyder said Silverman used "divisive and inappropriate" language, giving CPAC "no choice but to return his money."

Christian conservatives bristled at CPAC's initial willingness to let the atheist group participate. Family Research Council president Tony Perkins, in an e-mail to CNN's Dan Merica (who first reported the group's dismissal), asked, "Does the American Conservative Union really think the liberties and values they seek to preserve can be maintained when they partner with individuals and organizations that are undermining the understanding that our liberties come from God? Thomas Jefferson warned against such nonsense."