Organized religion cannot go into government. The government certainly can prohibit the free exercise of religion; check Reynolds v. U.S. 1879 for such an example, or Warren Jeffs v. State of Texas.
However, religious values of people do inform how government works, such as the House, the Senate, and SCOTUS. That does not mean the government gets to tell kids how and when and what to pray to in public schools.
It did before atheists got neutral prayer out of schools.
Government never told kids how and when and what to pray.
When we had neutral prayer it never indoctrinated any religion. Your parents had the right to teach you if there was a God or not. And that you had the right to not say the prayer.
Now it has become, you don't have the right to bring your religion into school or public expression, or government.
That is a direct violation of our constitutional rights.
Because of this we have not able to teach very much about US History because too much religion was interwoven into it.
We were a Christian nation at the beginning and we are Christian nation now.
We have the right to celebrate Christmas in our schools, on our government buildings on our city streets and in our stores.
The minority has now ruled over the majority and that is completely unconstitutional.
Jesus is the reason for the season and the minority of atheists and a few others are trying to shut it up.
It is prohibiting the free exercise (unconstituioal)