Joshua, you may not realize it, but you've already basically answered your own question. As a general rule (though there are exceptions to this), Confessions are not something that people get together, sort through several confessions which people have already made, and decide which one they think is best. For the most part, such would not actually be a true confession. Rather, we either 1.) Write confessions, or 2.) Receive them in the church handed down to us. As has been pointed out in another thread, our confession defines our church; and so, becoming a part of the church, we inherit its confession. Thus, since we (some of us) belong to churches which have their historic roots in English or Scottish Presbyterianism, we continue to confess the Confession handed down to us through generations; those churches which came from other parts of Europe continue to use the 3FU. There are not, however, many (actually, I think there are not any, though I would be interested in finding out) churches in America who have their roots in the Swiss Reformed churches, or any others (e.g., the Romanian Reformed churches) which received the Second Helvetic.
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Wayne Sparkman, you always seem to be able to easily address certain historical matters: do you know of any churches in America which have historically been governed by the Second Helvetic? I realize that at least a few denominations here include it in the book of confessions and other such materials; but have there been any here in which it has had a "more" official and historical role?