There is some interest in the upcoming British election, and the renaissance of the Liberal Democrats under Nick Clegg. See this article in The New York Times about the rise of the Liberal Democrats at the expense of the two traditional parties of power, Labour and the Tories. One interesting fact from an American perspective is that Nick Clegg is an admitted atheist, though his children are being raised Roman Catholic by his wife. Of course the lack of faith of British politicians isn’t that new, two Prime Ministers were not even nominal believers, Clement Attlee was an agnostic and James Callaghan was an atheist.
This is of course in sharp contrast with the United States where all politicians operationally have to avow a religious affiliation, and the higher that a politician ascends up the ladder of achievement the more vocal and thorough the assertions of sincere faith have to become. And yet it is Britain which has an established church, where the head of state is the head of the church, and, religiously oriented schools receive public funding.
There are many models rooted in history one could propose, but the facts as they are would probably be unlikely to be inferred from prior axioms. It’s a reminder that human social affairs are the outcome of messy dynamics, and observation is often far easier than deep analysis. In 1800 one would reasonably have expected that it was in the United States where “infidel” politicians would flourish, and yet that has not been so.