Meghan Snyder, spokeswoman for CPAC, said American Atheists were included in the confab because “conservatives have always stood for freedom of religion and freedom of expression.”

“The folks we have been working with stand for many of the same Liberty-oriented policies and principles we stand for,” Snyder said in an e-mail to CNN.

Tony Perkins, president of the Christian conservative think-tank Family Research Council, doesn’t see it that way. In an email to CNN, a rankled Perkins wrote that the atheist group does “not seek to add their voice to the chorus of freedom.”

“CPAC’s mission is to be an umbrella for conservative organizations that advance liberty, traditional values and our national defense,” said Perkins, who spokes at CPAC in 2012. “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.”