From time to time it's useful to review and reflect upon an important General Conference address by President Marion G. Romney, delivered in October 1975.
Many Latter-day Saints, especially those of the rising generation, have no idea about the connection between the Book of Mormon and America.
President Romney explained how the Book of Mormon relates to America's history and future, noting that both the Nephites and Jaredites were destroyed at Cumorah in western New York. He had visited the Palmyra area earlier that year.
In the western part of the state of New York near Palmyra is a prominent hill known as the “hill Cumorah.” (Morm. 6:6.) On July twenty-fifth of this year, as I stood on the crest of that hill admiring with awe the breathtaking panorama which stretched out before me on every hand, my mind reverted to the events which occurred in that vicinity some twenty-five centuries ago—events which brought to an end the great Jaredite nation....
As I contemplated this tragic scene from the crest of Cumorah and viewed the beautiful land of the Restoration as it appears today, I cried in my soul, “How could it have happened?” ...
This second civilization to which I refer, the Nephites, flourished in America between 600 and 400. Their civilization came to an end for the same reason, at the same place, and in the same manner as did the Jaredites’....
The tragic fate of the Jaredite and the Nephite civilizations is proof positive that the Lord meant it when he said that this “is a land of promise; and whatsoever nation shall possess it shall serve God, or they shall be swept off when the fulness of his wrath shall come upon them. And the fulness of his wrath cometh upon them when they are ripened in iniquity.” (Ether 2:9.)
President Romney addressed not only members of the Church, but also nonmembers.
Now my beloved brethren and sisters everywhere, both members of the Church and nonmembers, I bear you my personal witness that I know that the things I have presented to you today are true—both those pertaining to past events and those pertaining to events yet to come. The issue we face is clear and well defined. The choice is ours. The question is: Shall we of this dispensation repent and obey the laws of the God of the land, who is Jesus Christ, or shall we continue to defy them until we ripen in iniquity?
All around us we see evidence of the answer to his question.
Here is the entire sermon.