There is a theory in science developed by Karl Popper that instead of using inductive reasoning, one uses empirical falsification to prove a hypotheses. For example, verifying the claim “All swans are white” would logically require observing all swans, which is not technologically possible. In contrast, the observation of a single black swan is technologically reasonable and sufficient to logically falsify the claim. So instead of trying to prove something true, you can look and see if the claim is falsifiable.
Relating this to religion in general, and to Mormonism in specific, we can look at lots of truth claims and categorize then as either falsifiable, or non-falsifiable.
The religious belief in a supreme being, or God, is non-falsifiable. One can believe it of not. But it cannot be falsified. It cannot be proven there is no God. There are also lots of claims that are falsifiable. For example, the claim that the Book of Abraham is a translation of ancient records written by the hand of Abraham is falsifiable. So what to the apologist do? They move the goal posts, and claim the papyrus was just catalyst for Joseph Smith to receive revelation and write the Book of Abraham. Now this becomes Non-falsifiable.
Apologist will move to more non-falsifiable claims as the falsifiable claims are proven wrong. Horses in the Book of Mormon? Falsifiable. BofM people used the word horse for a tapir, which is found in the Americas; non-falsifiable. The BofM is a true history of people in Americas, with two million people killed in a single battle (Ether 15:2); Falsifiable. . The BofM should not be used as a history book, but as a spiritual book of gospel teachings; Non-falsifiable. The Word of Wisdom is a health code; falsifiable. The Word of Wisdom is a law of obedience; non-falsifiable. Pay tithing, reap worldly wealth; falsifiable. Pay tithing and store up blessings in Heaven; non-falsifiable. Garments provide physical protection; falsifiable. Garments provide spiritual protection; non-falsifiable.
You will notice a trend. The physical, real world benefits, when proven falsifiable, are then re-framed into spiritual benefits. Is the Mormon Church more falsifiable because of its relatively recent origin and thus more historical evidence is available, or maybe the boldness of its truth claims? What things do you see in the church that have been redefined from falsifiable claims to non-falsifiable?
 Two million casualties would make it the biggest battle in the history of the world, even surpassing the Battle of Stalingrad (1.8 million). Also, how would you provide food, waist management, etc. for two million people? Getting food alone would decimate the local forest of plant and animals in just a few days.