The text you link to is from an old religious book (published 1883) whose author writes in what is known as "purple prose":
prose that is too elaborate or ornate.
It is also written in highly periodic style:
6 Rhetoric a complex sentence, esp. one consisting of several clauses, constructed as part of a formal speech or oration.
I suppose the style reflects the author's rhapsodic enthusiasm for the prose of the King James Bible or religious tracts of the period.
Here the inclusion of the U.S. ("and the United States") is rendered as a parenthetical by means of commas, so that the verb may agree with a the singular subject ("America"). Why the author feels obliged to separate America into two entities (America and the United States) is beyond me. Clearly she feels deep in her bones that more words means better writing.
It is worth noting that this book is full of terrible, overblown writing, and I would not recommend using it as a model of grammar, style, or anything else worth imitating.