As a child, Razib Khan spent several weeks studying in a Bangladeshi madrasa. Heather Mac Donald once studied literary deconstructionism and clerked for a left-wing judge. In neither case did the education take. They are atheist conservatives  Mr. Khan an apostate to his family’s Islamic faith, Ms. Mac Donald to her left-wing education.

They are part of a small faction on the right: conservatives with no use for religion. Since 2008, they have been contributors to the blog Secular Right, where they argue that conservative values like small government, self-reliance and liberty can be defended without recourse to invisible deities or the religions that exalt them.

And they serve as public proof that an irreligious conservative can exist.

“A lot of religious conservatives say, ‘You can’t be conservative because you don’t believe in God,’ ” said Mr. Khan, 34, who was raised in New York and Oregon but whose grandfather was an imam in Bangladesh. “They say I am logically impossible, and I say, ‘Well I am possible because I am.’

“They assert your nonexistence, and you have to assert your existence.”

Neither Mr. Khan nor Ms. Mac Donald gainsays the historical connection between conservatism and religiosity. Influential conservatives, like the 18th-century Anglo-Irish statesman Edmund Burke, have been sympathetic toward religion in part because it endures.