I found an interview with the author about that book.... The interview is long but a quick read. Here are the highlights:
So the concern is that this particular special interest group has the same goal as every other special interest group in the country and that is to get hold of enough government power to legally impose their will on the entire nation...
The Christocrats "extremely sinister and dangerous agenda" is to officially recognize the US a "Christian" nation (which is equated to establishing a theocracy) by way of Constitutional Amendment... 
Hey, Chicken Little... It'll never happen... Ever.
Yes, by way of force and fraud... The current leadership in Washington learned those lessons well.
What's astonishing to me is the fact that people can so plainly see the danger of allowing government to hold such power, the legal ability to impose the will of one group on the rest of the entire nation, but those same people don't see that government power as the problem, they see the "wrong" groups getting that power as the problem. Instead, these people are giddy about the prospect of having their special interest use that power and seeing their will imposed on others by force of law.
Nobody has the Right to impose their will on others by force and it's a travesty that our government has devolved to the point where it's not only possible but commonplace. Keeping the "wrong" people from using that power is not the solution - banning that "extremely sinister and dangerous" power from government IS.
