CC, I’m afraid you are confusing two different things. The quotes you cite are accurate, but they have nothing to do with the so-called “White Horse Prophecy.” Please read up a little more.
Would you care to post the "other" prophecy of Joseph Smith that these apostles were referring to?
1928 Melvin J. Ballard, Conference Report, October 1928, p. 108
The Prophet Joseph told us that he saw the day when even the Constitution of the United States would be torn and hang as by a thread.
..... 1942 Harold B. Lee, Conference Report, April 1942, p. 87
...when we recall the prophecy of Joseph Smith who declared that “the time would come when ( the destiny and ) the Constitution of these United States would hang as it were by a thread,....I want to ask you to consider the meaning of that prophecy....