The separation of church and state is intended to provide citizens with the freedom of religion, a core value to American ideology. A Theocracy is a form of government where there is no separation between a religion and the government, Iran is a good example of this.
I can respond that I "believe in" your freedom to worship God through any religion and any church you choose, so long as your religious beliefs do not encroach on my freedom to do the same thing.
Do we have, or do we want, a separation of church and state in the United States?
Worship, that is coalescing as a group behind some ideal, is what people do naturally. It is instinctive to our survival as a species. It shows itself in the most basic of economies, the tribe. However, the ideal that different groups of people coalesce around can be problematic. If a requirement of your belief system requires that I die, then that is a problem.
"America is a nation of laws" is an ideal that some people coalesce around. Does that sentence proclaim a separation of church and state, or does it proclaim that the state is a church?
To be free of a nation of laws is precisely what drove people to come to the United States in the first place. To be free of a nation of laws is what gave birth to the phrase, "separation of church and state". Every law bleeds away freedom. To a degree, I want that. I want to limit your ability to prey upon me or my property. I "may" want to limit your ability to your free expression of life if I have to see or listen to it.
The question is "what does the state do" in response to what I want. When I want something that you don't want, what happens? If a separation of church and state means a nation of laws is the result, then no, I do not believe in it. If a separation of church and state means a nation of considerable freedom and liberty to live life as you and I want to live our lives, then yes I do believe in it.
Let me close by asking you a question. Do you believe in a separation of church and state if that separation means that the state becomes the church your neighbor worships?