Please this recent FR thread and my post on the subject: Reagan Was Right, ACU Wrong: Atheism Is Enemy of America. I also direct your attention to the comment by FReeper stalwart xzins:
Conservatism is incompatible with atheism. Atheism is amoral and directionless. Conservatism has morality, meaning, purpose, and direction....all from God.
There is but one King in America and that's Almighty God.
It is impossible to be a conservative and be an atheist.
American conservatism is all about preserving the values and processes that have made this an exceptional nation.
Belief in God is the ultimate value.
“Endowed by their Creator with certain unalienable rights...”
If rights aren’t from God, but are instead some human philosophical conclusion, then those humans can change their minds.
So Ayn Rand wasn’t conservative? The great Russian-American writer Vladimir Nabokov was also an atheist and a staunch conservative who supported and the Vietnam War.