Here's what's being looked into at present:
After a great deal of research I am 95% convinced that the region referenced in the Beale pamphlet is in fact the same region in Colorado that was ceded to the US during the Adams Onis Treaty.
I actually like the possibility that ECS wasn't that far off when he suggested that the author of the pamphlet simply used existing writings in the creating of the Beale pamphlet, makes for a very reasonable possibility. However, there are two huge factors that suggest this wasn't the case.
I could understand one of the dates of deposits falling in line with the signing and ratification of the Adams Onis Treaty, this being simply coincidence, but when both dates of deposits are unmistakeably coinciding with both of these events with such exactness then coincidence has to be ruled out, the odds against such a coincidence being staggering. This can only mean that those deposit dates were either by author design or that that they were indeed real dates of deposits. Either way everything points to the Adams Onis Treaty having some significance in the tale.
Of additional interest in the Beale Pamphlet are the names offered, Marshall, Clay, Coles, Witcher, all of these men played a vital role in two areas, the first being that great debate over what would later be coined Manifest Destiny, and the second being their strong connection to James Monroe. What's interesting here is that James Monroe played pivotal roles in both the Louisiana Purchase and the Adams Onis Treaty. And in case you're having trouble placing him, “Cole” was Monroe's personal secretary.
Most of those who have researched the Beale mystery have done so from a treasure hunting perspective rather then from a political perspective, which I now believe the case to be. When we look at the Adams Onis Treaty we initially see Spain and the United States but there were other interest involved in, and holding influence over, those treaty negotiations. In fact, it now appears as if there was quite a bit of interest in the outcome of that ceded region in Colorado, perhaps none more concerned then Mexico. Third parties have always influenced treaties, so why not here as well?
The two deposits came from west to east in near perfect timing with, and after, both the signing and ratification of the Adams Onis Treaty. After the treaty had been ratified several key players changed their position on western expansion, this even including Jefferson himself. The question is, was there a different reason for this change of position then what history tells us? All the evidence reviewed and collected so far suggest that there was.
