Separation of Church and State

I am against mixing politics and religion not so much for the effect of religion on politics as much as for the perversion of religion by politics. Belief in God is Man's way of giving meaning to what otherwise appears to be a chaotic ultimately tragic existence. What does that have to do with politics? Why should anyone care which religion anyone else uses to meet this need? People who mix religion and politics are usually using religion to promote some political or other secular goal.