One of the principal early arguments to ascribe authorship is based on statements alleging that a one-time minister, Solomon Spalding, wrote a historical romance based on the premise that the Indians descend from a lost tribe of Israel. Although he died in 1816, it is argued that he took his manuscript to a publisher in Pittsburgh. Years later, a Baptist minister, Sidney Rigdon, came to possess it and plagiarized it, in particular adding some religious material, to become at least a precursor draft of the BOM text. Smith and Cowdery published it, having made modifications of their own to adapt it to their needs. Consequently, whether the text published in 1830 was the work mostly of Spalding, or Rigdon or Smith and Cowdery, the new bible is nothing more than a plagiarized version of Spalding's work.

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Sophisticated content analysis has been done in an attempt to provide independent evidence for the conclusion of the Spalding-Rigdon hypothesis. The results are far from proof, and are refuted by other equally good statisticians. For a researcher who feels he has very strong stylistic evidence for his hypothesis, there can be the temptation to feel so sure that the hypothesis is true that it can be used to prove the contingencies. This line of reasoning proceeds as follows. Since Smith plagiarized a Spalding-Rigdon BOM-precursor text (or so this research thinks he has shown), therefore "Rigdon must have provided it." Since he did, therefore "Rigdon must have known Smith or Cowdery." Since he did, he must have had a manuscript to provide. Since he did, "Rigdon must have found the time to dedicate himself to produce such a text." Since he did, "he had so much interest in the native American issues that he was motivated to do so." This mode of argument continues all the way down the chain to therefore, "Spalding wrote a history featuring Israelites." In this approach, the unproven hypothesis proves the chain of contingent premises upon which it rests. This is as fallacious as it gets.