"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;"
No religion is being established and no one is stopped from exercising their religion. It's constitutional.
It's still a claim that a God exists....whatever God that might be. I think the establishment of any such being violates that clause.
But it doesn't say what specific God, so it's not preferencing one religion over the other. It's kind of a generic thing. But then again, I'm no constitutional scholar.