While I'm not sure if I'd call "In God We Trust" an unconstitutional establishment of religion, I would certainly prefer that it be taken off money. I do not "trust in God", thank you very much, so why is my money speaking for me? I also hate the fact that it's used to justify required recitation of the pledge, as if two wrongs make a right (no, that would be three lefts). It's like clockwork, any time there is a debate over the pledge, you'll get a, "Oh, but it says In God We Trust on money, why don't you just stop spending money?" or something ridiculous like that. What exactly is it about money that made people think, "Hey, this stuff would sure look great with a reference to God on it" in the first place? I don't see the connection between money and God. I thought religion wasn't supposed to be about money. It seems more like something The Church would have had done in the 12th century.
And, well, yes, I completely agree with the premise of your posts that religion seems to (sadly) have a major place in US civics. I wish luck to anyone trying to get elected to public office who's publicly known not to be a follower of a mainstream religion. (At least in the majority of the country. Perhaps you could get away with it in certain parts of the Pacific or northern Atlantic coast, or if you're an ex-pro wrestler.)
Now, they all talk about how this country was founded on Christian principles, ad nauseam. Nevertheless, I think it was quite deliberate that there is only a single religious reference in the Constitution: "Done in Convention by the Unanimous Consent of the States present the Seventeenth Day of September in the Year of our Lord one thousand seven hundred and Eighty seven". Yes, the date. I contend that it is only recently that the Leadership of this Fine country (I think that old-school noun capitalization is starting to rub off on me) has felt it necessary to affirm our Trust in God and Existence under God. The Pledge has existed for a longer time WITHOUT a reference to God (1892-1954) than WITH one.
I can't vouch for this idea, but I think back then, it was more of a concern to people how effective the governance of candidates would be than how much "faith" they have (apparently that Someone Else will do the hard work for them while they go on ranch vacations for weeks at a time). Unfortunately, it also seems that a number of major political issues these days have a direct connection to religion, particularly abortion, that historically have not been important issues if they were issues at all and certainly aren't in other countries.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.