I think we can thank the founders for having the foresight to NOT allow government to mandate a particular belief system.
“Congress shall make no law respecting an ESTABLISHMENT of religion, or PROHIBITING 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.”
This was a genius move. Had this NOT been included as the first amendment to the constitution ANY religion could be MANDATED by congress, including Mormonism, Hinduism, Islam or anything else.
The government has no place telling anyone what they should believe in regards to religion or who or how they should worship religion.
No, it was not brilliant. James Madison opposed the enumeration of rights (which are infinite) because the government would soon come to regard those enumerated as the limit of our rights.
The body of the Constitution did not grant congress to establish a religion. Where did you find congressional power to mandate a religion?