"The Schwenkfelder Church has remained small: as of 2009 there are five congregations with about 2,500 members in southeastern Pennsylvania."
https://en.wikipedia.org/wiki/Schwenkfelder_Church
Yet this tiny church has produced *two* potential presidents of the United States. One--of whom I had long been aware--was Richard Schweiker, Reagan's choice for running mate in 1976.
https://en.wikipedia.org/wiki/Richard_Schweiker
But one thing I hadn't realized until very recently is that there was a *second* Schwenkfelder who might have become POTUS--Drew Lewis, Reagan's first Secretary of Transportation.
https://en.wikipedia.org/wiki/Andrew_L._Lewis OK, a nuclear attack wiping out everyone in the line of succession ahead of Lewis seems unlikely. But if before 1984, Vice President GHW Bush should die in, say, a helicopter accident, would Lewis be totally implausible as a replacement VP? (Some conservatives might be displeased by the choice of Lewis, who had been a Ford supporter in 1976. But Reagan didn't really have to worry about losing conservative support, and Lewis could be sold to them as the man who helped to break the air controller's union PATCO. Moreover, Lewis might help Reagan carry Pennsylvania--which, relatively speaking, was one of Reagan's weaker states--in 1984. True, Lewis had lost the Pennsylvania governorship race in 1974,
https://en.wikipedia.org/wiki/Pennsylvania_gubernatorial_election,_1974 but that was after all a very Democratic year.)
In any event, I don't know of any other church of comparable size that has produced two plausible POTUSes.