I think a politician has to recognise the cultural realities of life - and religion still forms a major part of our society, rightly or wrongly.
Where it gets worrying is when politicians allow religion or faith to drive their policy making, in contradiction to evidence or science.
It also seems wrong to me that in places like the USA, you would be extremely unlikely to be elected if you were a self-declared atheist - So despite the constitution making the statement of being a secular nation with religious freedom for all, it now seems that to become a senior political figure you have to declare a faith and preferably christian.
In 2010, religion and faith hold far too much sway in global political decision making, and the more fundamentalist the religion, the more of an anchor on cultural and humanitarian development.