There is a tendency for the claims of the Book of Mormon to come up any time theories about Israelites coming to the Americas in any form are discussed.
Even when it comes up in completely secular contexts like on Coast to Coast AM just talking about Pre-Colombian contact in general, someone will say "maybe we shouldn't write off the Mormons' claims", but The Book of Mormon actually makes a point out of the new world civilizations NOT having contact with the Old World. Part of God's Promise to Lehi was that God would protect his land from being found by the Nations. So at least from when Lehi arrives in the 6th century BC to when the narrative of the Book of Mormon ends in 422 AD, there can be no trans-Atlantic or trans-Pacific contact according to Mormonism, but I believe there certainly was.
And when a History channel show like America Unearthed discusses the possibility without bringing up the Book of Mormon, Mormons see it as some kind of anti-Mormon conspiracy and so make a video mocking Scott Wolter (who is easy to mock, he's a clown who thinks he's Indiana Jones).
Many of my fellow Fundamentalist Sola Scriptura Christians feel the need to oppose the idea of any Israelite contribution to Pre-Columbian American History simply for the sake of opposing Mormonism. This unfortunately I feel makes them come off not unlike the Bible skeptics we like to make fun of, who essentially feel "if The Bible said it happened it can't possibly be even remotely true".
But there are Mormons in the public eye who don't advertise their Mormonism, bringing the subject of Israelites in America up without telling people the Book of Mormon is the reason for their interest in the subject. Like Glenn Beck. So concern that this subject could be a gateway drug to Mormonism is a legit concern.
First of all The Book of Mormon is NOT about the Lost Tribes or deported Northern Israelites.
Lehi's tribal identity may be identified as Manasseh, but he didn't leave the Holy Land till the fall of Jerusalem. Some Northern Israelites were left behind, especially in West Manasseh, Lehi's family may have been meant to be among those who migrated South for Josiah or Hezekiah's Passovers.
In fact one Mormon blog I've looked at called the NephiCode makes a point of distinguishing between the House of Lehi and their promises/destiny, and the Diaspora of either Kingdom. In fact it's not uncommon for Mormons to believe in British Israelism. But also Joseph Smith had claimed that at least some of the Lost Tribes were taken to another planet. I'm in no position to mock that view since I've argued something similar for my own totally separate reasons.
And Lehi left by sea (as did the Jaredites) in Arabia, because Joseph Smith imagined all this before the bearing strait hypothesis became the standard.
So the genetic affinity Native Americans have to East Asia, in both their Y-Chormosone and Mithocondrial DNA Haplogroups is a problem for the Book of Mormon.
But not for me since I don't think Israelites were the only people involved. And because I believe they traveled across Asia, intermingled with East Asian populations, and became ancestral to people groups in East Asia, before some of them came to the Americas and mingled with people already here. I talk about my theories on Israelite DNA here.
Many Mormons now insist the Book of Mormon does leave room for other populations, this mostly correlates to if they hold a Limited Geography interpretation rather then a Hemispheric one.
If a limited Geography model were the correct interpretation, only the Heartland Model would be plausible, because Joseph Smith's intent was definitely entirely about making special the land he lived in, drawing on prior speculation about the Missipian Mound Builders.
But the only DNA support the Heartlanders have cited is mtDNA Haplogroup X, which is mater-lineal and the least common of ones fond among Native Americans.
The NephiCode blog I mentioned stands by believing all Native Americans of both continents are Lamanites. And their answer to the DNA issue? That when God changed the skin color of the Lamanites to punish them making them look how modern Native Americans look (yes this was brought up on a Mormon blog talking to Mormons, it's not something the Godmakers made up), God also changed their DNA.
That is of course absurd. The parts of DNA used for ancestry studies are completely separate from the parts related to skin tone and eye muscle (the reason East Asians peoples' eyes look "slanted' is really because they have more eye muscle) and other ethnic features.
But if God supernaturally changed their DNA to erase their Hebrewness. They should simply have completely unique Haplogroups. Instead this Mormon blog asserted God changed their DNA to PUNISH them by making them genetically similar to East Asians. So a Mormon doctrine that was once only racist against Native Americans is now racist against East Asians too. Great work guys.
Second of all, The Book of Mormon claims the Nephites practiced strict Mosiac Judaism, but not the Lamanites.
I believe it's clearly stated in II Kings that the Lost Tribes ceased following Yahweh and lost their Israelite identity. A few remnants may have been different, and such groups have been found in Asia. So some Hebraic or Mosaic clues could have come with them, but mostly I expect to see the Lost Tribes being polytheistic pagans until they encountered Christianity, and that the vast majority stopped even speaking Hebrew before they came here.
Once again my view is more compatible with the Evidence. Because while the occasional random controversial seemingly Hebrew relic has been found, most of the Native Americans, including the Mississippian culture (who the Heartland model sees as the Nephites) were polytheistic pagans, many of whom practiced Human Sacrifice. And the languages spoken were not Semitic.
Third of all, the Israelites in America issue isn't the Book of Mormon's real doctrinal problem.
On a different blog I'll maybe some day talk about how the Book of Mormon doesn't even agree with later developed LDS doctrine, often agreeing with The Bible over it. But the Book of Mormon is definitely heretical.
First and foremost, Nephi prophesied that the Bible will be a "stumbling block". Now many Mormons disagree on how harsh this is to The Bible. Some off shoots like Temple Lot say they believe the King James Bible "so far as it has been translated correctly" implying they see the problem only in how it's translated not in the actual Masoretic or Textus Receptus texts.
LDS Mormons debate back and forth. Some saying the only things in The Bible that Mormons should agree with are what the Book of Mormon or other Mormon Scriptures explicitly endorse. Others saying all the potential "stumbling block" issues are what modern Mormon Revelations have addressed so anything in The Bible not in conflict with other Mormon scripture should be taken as God's Word. Essentially Mormons treat The Bible how Biblical Christians sometimes treat Apocryphal books that interest us.
Point remains however, the seed for doubting God's word is planted, and from that all kinds of heretical madness has developed that the Book of Mormon itself didn't talk about. Like Cosmic Pluralism and Polytheism.
But the reason this post is relevant for my Prophecy Blog is because of Mormon Eschatology.
The ancient Nephite Prophets of The Book of Mormon foretell The United States of America, referring to it as a Great Nation appointed by God to do his will. In other words, American Exceptionalism, Divine Providence and Manifest Destiny, all those ideas Christians should condemn as Patriotic Idolatry but instead fully support, that is all Canonical Scripture for Mormons.
Mormons believe America is the Promised Land, but not as a replacement for Israel. They believe Israel still has it's destiny (Joseph Smith actually was an early Christian Zionist), but they believe New Jerusalem will be in America. Old Jerusalem for the Old World and New Jerusalem for the New World. And because most modern Futurist Premillenial Evangelicals also believe New Jerusalem is distinct from Yahweh-Shammah of Ezekiel, they aren't adequately prepared to refute that false doctrine.
I have shown on this blog that New Jerusalem/Heavenly Zion is the same as Yahweh-Shammah and will be in Israel, where the current Jerusalem is.
Add to that Joseph Smith's separate Prophecies about "One Mighty and Strong" and the White Horse Prophecy. And the potential for the Mormon church to be a seed for an American Antichrist is something to be concerned about. And I also have my suspicions that Revelation 9 may begin with a counterfeit of the descend of New Jerusalem.