Religious Freedom.

(Constitutional) Amendment 1 - Religious and Political Freedom:
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 of the right of the people peaceably to assemble, and to petition the government for a redress of grievances.

Italics added for emphasis.

In other words - the government cannot establish one national religion (ie. The Church of England) nor can it restrict the "free exercise" of religion. And yet, today there are people who have twisted this into, "You can't even mention God in a public place because it offends me." Excuse me? Oh, yes, I can. The moment you try to stop me - for whatever humanist, misguided reasons you might have - you are "prohibiting" my "free exercise thereof". Your right to not be offended is *not* actually protected, (and frankly, you need to grow-up if someone mentioning God upsets you) but my right to freely exercise my religion *is* protected.

Like it or not, this is one of the foundations of our country. If it's been too long since you've looked over the Constitution and Bill of Rights, perhaps it's time you WENT BACK AND GAVE THEM A THOROUGH READING.