Isaiah and the Book of Mormon

Deutero-Isaiah (or is this one Trito?) writing about Jesus. 

If the fact that Isaiah was written by more than one person isn't enough to bring on at least a little doubt, consider this fact: anything from Isaiah chapters 40-66 that made it into The Book of Mormon either verbatim, slightly altered, or paraphrased (1 Nephi 10:8, 13:37, 17:36, 20-21, 22:8 & 10-11; 2 Nephi 6:6-7 & 16-18, 7-8, 9:50-51, 10:9, 26:25; Mosiah 12:21-24, 14, 15:10-11 & 14-18 & 29-31; 3 Nephi 16:18-20, 21:8-10 & 29, 22; Moroni 10:31) was written after Lehi & Co. left Jerusalem. So how the hell did they make it onto the brass plates and over to the New World?

You could doubt the authorship of The Book of Mormon at this point if you wanted to. Or you could simply doubt the scholarly understanding that Isaiah was written by multiple authors on into the years following Lehi's departure. After all, we know that The Book of Mormon is true and that "the wisdom of this world is foolishness" (1 Corinthians 3:19).

Problem solved! Except there's still the whole plagiarism thing you have to consider too...