It's an official proclamation so it presumably has the same authority and is as official as the endlessly quoted proclamation on the family. Anyway, the line that interests me is this one:
He has revealed the origin and the records of the aboriginal tribes of America, and their future destiny.-And we know it.
That quote doesn't seem to offer much wiggle room. They are obviously referring to the Book of Mormon. They are also claiming that it reveals the origin of the aboriginal tribes of America. They also seem pretty sure about this, they are not content to just proclaim it, they also emphasize that they know it.
The logical conclusions seem to be: 1) They saw this continent as empty prior to the records of the Book of Mormon, 2) The migrations listed in the Book of Mormon are the origins of the inhabitants of the Americas, and 3) The Book of Mormon does not describe a limited geography, at least with respect to populations. The events of the book may take place in a limited area, but the populations resulting from the Book of Mormon migrations are hemispherical, not limited.
Do apologists attack the official status of the proclamation (thereby nullifying the proclamation on the family and rendering prop 8 actions incomprehensible)? Or do they find a way to harmonize the language with limited geography theories? Or is there something else I can't think of?