"from either perspective"
How well reasoned and .... moderate. It is true that the USC has been used to force Christianity on others. I can't think of any examples offhand, but I'm sure there are many. And that would certainly excuse the Christians being made into second class citizens today. < /sarcasm >
Are you suggesting there wouldn't ever arise a problem with religious oppression if our first amendment weren't in effect? The history of the Reformation should strongly suggest otherwise. Despite considering themselves protestants, the Puritans who immigrated to America built some of the most religiously oppressive communities in history. Oh no, you can't dismiss the entire reason for the first amendment with a simple sarcasm tag. These tendencies toward tyranny are inborn in every human being, just as are the rights we claim. Man's own weakness is precisely why we established checks on political power, including those who would distort religion to those ends.