"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 the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."The First Amendment to the US Constitution provides incremental euvoluntarism over existing contemporary European institutions. In much of Europe, even today, the set of state-sanctioned religions tends to contain few enough elements that you can count them on your fingers and toes (apologies to our readers with phalangeal fusion, amputations, et al).
There seem to be two questions here:
1) shall I join a religion? and
2) which religion shall I join?
The answer to the second question is marginally more euvoluntary in the United States. A quick query into the database at my day job returns 103 distinct religious denominations recognized by the Department of the Army, and surely there exist more than that in toto. The US Constitution eases the BATNA for any particular religion by allowing more and varied alternatives.
The answer to the first question may be trickier. Identifying as atheist outside of certain elite circles carries with it piles of opprobrium. Man cannot live on bread alone and the lone soul withers. Professing faithlessness is not a euvoluntary decision, as this decision oft comes saddled with consequences.
Declaration of faith is one of the few Enlightenment-era sacred cows whose kernel persists. Even if belief is not euvoluntary, few if any Americans would be willing to use the coercive power of the state to regulate people's voluntary choice what to believe about supernatural forces. In some unrelated research, I found that there was quite a bit of "disagree" or 'strongly disagree" to questions of "allow Satanist to speak" or "allow Communist to speak". People seem to be much more amenable to censorship of speech than to regulation of religious belief (at least as long as the religion isn't too weird: I think there's still a strong anti-Wicca/New Age/C'thulean streak running through the Heartland). I doubt you'll ever hear of a Southern Baptist lobby leaning on Congress to shut down Presbyterian churches.
I'm a bit curious about the potential for soft paternalism here. Given that the private costs of atheism are high and that the self-appointed task of paternalists is to protect people from their own bad decisions, why hasn't anyone proposed default rules for religious faith? Why not have opt-out baptism or churches strategically arranged in an attractive display in front of day care centers? Shouldn't we be doing more to "nudge" people into pews?
If you find these suggestions offensive, please let me know where you draw the distinction between nudging people into church and nudging them into a defined-contribution 401-k or towards the salad bar.