That will take a while, I think. When I was in elementary school, we had a brief bible reading (the Old Testament, for the Jewish kids), and then said the Lord's Prayer.
Nobody really took it seriously. It was just something they made us do.
And then at some point the Supreme Court decided that was wrong, so it stopped. Nobody I knew thought that was a big deal, either. And I lived in what at the time would have been considered staunchly Republican areas.