Most protestant ministers believe in the idea of their being a God, but do not actually believe that there is aa all powerful personal entity called God. I can say this with some authority because I trained as a minister in the early 1990's, during which I read Divinity at Edinburgh alongside many people who are now in the midst of careers as priests and ministers.
In spite of the very liberal application of source criticism and modern thinking by the faculty staff which meant that most students did not believe in the necessity of the virgin birth and many other tenents of traditional (or as they saw it outdated and old fashioned) Christianity, they all graduated with implicit faith in "Godness".
I call this a belief in "Godness" rather than belief in "God" because it sees a desirability in believing that if there was a God then this would make life better or more meaningful. It could also be described as wishful thinking, self deception or, dare I say, delusion.
These Christians see the apparent moral good which religion does for those who are involved in it. Of course that could be a case of "birds of a feather flocking together", but you do get cases of people's whose behaviour is modified due to the influence of Christian thought or Christian community.
From an evolutionary stand point there may well be some benefit to the group of passing on moral teachings from one generaton to the next. The church (especially in Scotland) has tended to concentrate on passing on moral teachings rather than belief in an ultimate being called God, which is why I think that belief in "Godness" has become predominant here. It may also be the legacy of some of our great thinkers like David Hume.
This belief in "Godness" cannot be shaken by rational argument, because even if science was able to prove without doubt that there was no God, this could not affect someones belief in the idea of their being a God. The idea itself is the object of faith rather than God himself. This explains why liberal clergy like Richard Harries continue to stick to their apparent belief in God in spite of their denial of many traditional Christian teachings and their accpetance of science. They do not believe in God, they just believe in the idea of their being a God.
Another aspect of belief which I noted during a brief flirtation with pentecostalism was a very close parallel between romantic love and faith in Jesus. I say faith in Jesus rather than God because this does seem to introduce a personally knowable aspect to the Yahweh. Indeed thats what Christians claim about Jesus. There seemed to be a lot of sublimated sexuality going on in charismatic worship when I was involved in it. This is one reason why it attracts so many young people who are believers, especially young women. Because they have decided to be chaste and not have romantic relationships with other people until they find a prospective husband, Jesus becomes a substitute lover or husband (as it is less kindly put by others a "subby hubby"). Certainly in my own life I have seen periods of marital estrangement bring me apparently closer to Jesus, yet as the relationship with my wife improved I seemed to become more estranged from Jesus. Looking at it dispassionately I can now see a clear connection between romantic attachment and faith. In fact CS Lewis wrote about his problems with the idea of romantic love at the same time as he was writing about his problems believing in God. Interestingly he came to believe in God and romantic love at around the same time.
It could well be that belif in a personallly knowable God (Jesus) could be a misfiring of the Darwinian need to form a monogamous emotional attachment to one person for the purpose of rearing children.This could explain why Christianity has become so successful in the west, although I am also sure that the belief in life after death was a huge selling point for Christianity in the aftermath two world wars which involved great loss of life.
There were noteably a number of religious revivals in the 1920's 30's and late 40's in the USA and Great Britain. Its also noteable that Spiritualism had large periods of growth after each world war with even Air Chief Marshal Lord Dowding becoming a leader in the spiritualist movement after having to deal with so many of his men dying in combat.