It seems that these verses are related. The first says that the consumption decreed by God will make a full end of all nations. Whatever we believe about the destiny of the United States, we know that our nation must come to a full end, as this prophecy must be fulfilled.
D&C 87:6 And thus, with the sword and by bloodshed the inhabitants of the earth shall mourn; and with famine, and plague, and earthquake, and the thunder of heaven, and the fierce and vivid lightning also, shall the inhabitants of the earth be made to feel the wrath, and indignation, and chastening hand of an Almighty God, until the consumption decreed hath made a full end of all nations;
And that verse is related to a verse in the doctrine and covenants. All nations having come to a full end, Christ claims his place as the king of the whole earth.
Revelation 11:15 And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdom of our Lord, and of his Christ; and he shall reign forever and ever.