The issue is not faith, accept that moderate religious voters have allowed because they need their faith, as you stated ,the political influence of extreme Christians to govern and move into important political positions throughout federal, state and local governments.
The discussion of the author was the danger of having people, who believe the second coming of Christ is happening in their lifetime and that the rapture will take them to heaven and save them from armageddon ,in power and making the decisions for our lives.
His argument is that it is the same as electing an official that believes if he flies a plane into the twin towers he will gain heaven.
My personal take was he has a valid argument and it is a good reminder why Church and State need continuing separation.
The Rapture did not even enter Christianity until the 1950's when a religious sect in Germany had a leader who introduced it to his followers.
I am totally in agreement with you. IMHO Mr. Bush believes that it his job to "Bring it on". As a believer in Christ it makes me sick to see what people like that do when they get into power.