I've seen a fair number of sf stories (submitted to SH over the years) set in a future USA in which religion has been outlawed or religious people are persecuted. I find that scenario implausible.
These stories usually appear to be set within the next hundred years or so, and they're usually in futures in which America is still recognizably more or less what it is today, except that Federal laws have been passed against religious belief and/or practice.
I suppose this trope is, in essence, a discrimiflip, and subject to the usual problems of such. But unlike most discrimiflips I've seen, the persecuted-religious-people trope is usually set in the near future, rather than in an invented world, which (for me as a reader) raises the question of whether it's plausible.
The US has had religion deeply embedded in its national psyche for over two hundred years now. It was founded by Christians. Wikipedia notes that “Chaplains have served in the various branches of the United States armed forces since their formation, including in the Continental Army during the American Revolution.” We've had “In God We Trust” written on at least some of our currency since 1864; it's been an official motto of the country since 1956. In 2011, a Gallup poll indicated that 92% of Americans believe in God.
And then there's this:
On February 20, 1955, President Dwight D. Eisenhower stated that “Recognition of the Supreme Being is the first, the most basic, expression of Americanism.” President Gerald Ford agreed with and repeated this statement in 1974.
—Wikipedia, “Religion in the United States”
I haven't fact-checked any of those Wikipedia entries, so some of the details may be wrong. But the gist of the above matches my impressions of the way things are and have been in the US.
And these are not the characteristics of a country that's going to go hardcore atheist anytime soon.
I'm sure that everyday life for a lot of people is a lot more secular than it was a hundred years ago. It wouldn't surprise me if people are less motivated by religion than they were then, or less dedicated to it, or less likely to go a place of worship regularly. And atheism has certainly been gaining visibility in recent years.
But even extrapolating that trend out a hundred years into the future, I just can't see us arriving at an America in which all religious people are persecuted minorities. I can't even see us, in the next hundred years, getting to a point where more than half of Americans are atheists.
I know that societies change, sometimes radically, sometimes in relatively short periods. But here's another bit from Wikipedia, about atheism in the US: “In January 2007, California Congressman Pete Stark became the first openly atheist member of Congress. He described himself as ‘a Unitarian who does not believe in a Supreme Being.’” So that's one openly atheist member of Congress, out of over 500 members of Congress at the time, and after 200+ years of our having a Congress.
I just don't see us going from that situation to religion being outlawed in the next hundred years. So when I see these stories, I have a really hard time suspending my disbelief.
(Please don't take this as an invitation to bash either religion or atheism. I'm only talking narrowly about a specific trope that I've seen in a bunch of stories.)
(Written in March 2012, but didn't get around to posting 'til now.)