Section 87 contains Joseph Smith's prophecy of the Civil War. Growing up, I always understood that the remnants mentioned in verse 5 were the Laminites, sense it makes a distinction between them and the Gentiles.
Now that the latest DNA research has caused the COB to back away from identifying all Native Americans as descended from Lehi, it begs the question, who are now classified as remnants?
1 Verily, thus saith the Lord concerning the wars that will shortly come to pass, beginning at the rebellion of South Carolina, which will eventually terminate in the death and misery of many souls; 2 And the time will come that war will be poured out upon all nations, beginning at this place. 3 For behold, the Southern States shall be divided against the Northern States, and the Southern States will call on other nations, even the nation of Great Britain, as it is called, and they shall also call upon other nations, in order to defend themselves against other nations; and then war shall be poured out upon all nations. 4 And it shall come to pass, after many days, slaves shall rise up against their masters, who shall be marshaled and disciplined for war. 5 And it shall come to pass also that the remnants who are left of the land will marshal themselves, and shall become exceedingly angry, and shall vex the Gentiles with a sore vexation.
I assume this means the indigineous peoples who are the 'remnants of the land' regardless of their DNA paternity. I suspect it will also involve a lot of mixed blood.
I think it will play out that the classes that the United States and Canada hold as nothing will grow powerful and 'blossom as the rose'. The time of the Gentiles will be over. My time. Unless the Gentiles will repent (I think it unlikely) they will be torn in pieces and there will be none to deliver. I suspect this may refer to a reduction in political and economic power though it could just as easily refer to some sort of war. The only escape for the Gentiles is repentance and to work righteousness (i.e. will not be averted by immigration reform).
How this relates to other LDS prophecy I'm not sure.
"Surely he knows that DCP, The Nehor, Lamanite, and other key apologists..." -Scratch clarifying my status in apologetics "I admit it; I'm a petty, petty man." -Some Schmo