First, I think it's a good idea to name Newt Gingrich in the OP, not require people to follow a link to figure out what the topic is.
Second, as much as I detest Gingrich and people like him, what he intended to say seems clear to me. I am pretty sure he was saying that atheists, by supporting a wall of separation between Church and State as well as civil liberties that prevent profiling based on race or religion, are creating an opening through which radical Islam could get a foothold in the US. He thinks that having Christianity as the religion favored by government is necessary to prevent an eventual coup by Islamists. You can disagree with his analysis - I do - but it isn't nonsensical gibberish (e.g., that atheists are radical Islamists).
