I write this post from a Christian point of view. Others can make similar arguments from other religious views. Arguments for a secular state can be made from a non religious view as well.
I believe that in our modern world we need to allow space for all religions and non religious views to co exist peacefully. To achieve this the state should be neutral in relation to these questions. With different moral codes in modern societies we need to let private moral views to remain private.
Christianity was born in persecution and suffering. When the Roman Emperor became Christian he issued the edict of Milan. This edict granted freedom to all religions. It just asked the different religions to pray to its God or gods for the Emperor. It was only around 80 years after Constantine died that the Roman Empire became Christian. Christian churches have 2 views to the state, a state where freedom and peace reign or the temptation of a state church. Unfortunately in the history of Christianity the temptation of theocracy was taken in the main.Church leader not satisfied with preaching it’s faith sought to be politicians as well to the general misery of humanity.
Before the Roman Empire the Persian Empire of Cyrus the Great gave freedom to all the religions in his empire. The Greeks saw the Persians as a threat but the Jews saw him as a liberator.
The former US President Jimmy Carter is a Christian. He is a well read as well as a strong believer. He is also a strong believer in the separation of the church and the state. When he was President he insured that as President he conducted his political life in a secular way. He practiced his religion in church and in his residence. His office of President was conducted in a secular way.
A new society the Hitchens and Brown society seeks to advance the principles of secular republicanism and social justice for all. Personally as a Christian I believe a secular state guarantees my freedom of religion. Theocracy harms my faith. Best of luck to the new society.
John O Brien.