The Founders expressly wanted to keep religion out of the government process.
Nope, that is not what the First Amendment says at all. In fact, there are abundant speeches by people such as George Washington that are directly contrary to that.
The First Amendment says congress(not the states) shall pass no law respecting an establishment of religion nor prohibiting the free exercise thereof. That means no official national religion and no bans on practicing religion. Somehow the judicial dictators have managed to turn those simple concepts into a confused mass of conflicting opinions that have produced literally the exact opposite of what the Founders envisioned.