They an important historical early codification of law, but I don’t think the problem with schools and the legal system is that they don’t preach the 10 Commandments.
Nope. The problem with the schools and the legal system is that they frequently preach open defiance of them.
Maybe and maybe not. But life was a lot more civilized when the public schools respected the Word of God and encouraged students to live their own life accordingly.
America was also a much stronger nation then; in terms of culture, economically, financially, and as a respected world power, than without the Christian God (of Abraham, Isaac, and Jacob). I am of the opinion this is not a coincidence.