I'm vaguely familiar with the outline of the conspiracy: a group of American politicians, military officers, etc., possibly led by influential founding father Aaron Burr, planned to launch an invasion of (here's where things get fuzzy for me) the area comprising the Louisiana Purchase? And also parts of New Spain, i.e. Texas and Northwestern Mexico.
What piqued my interest, though, was reading about the history of expulsions of serving Congressmen from the US Congress. A Senator John Smith of Ohio was, apparently, accused of supporting the conspiracy, but was ultimately exonerated or not expelled. This made me wonder what the scope of the so-called Burr Conspiracy was.
How deeply was Burr himself involved? What did the conspirators, if they successfully gained control of the Western lands, intend to do with them? Simply annex them to the United States, or were there more independently-minded goals for the new additions? Were any substantial steps made towards carrying out the expedition or invasion? To sum up, what exactly was the scope of the conspiracy, and how close was it to success, if any substantial steps were made at all?
There is not much agreement among historians as to whether there was a conspiracy or what it might have been about. All that is known without dispute is that Burr gathered a small band of armed men on an island in the Ohio River. He was charged with treason, accused somewhat vaguely of trying to detach the western states from the Union, invade Mexico, and found a new empire with himself as emperor. He was acquitted, and in truth the evidence didn't support the charges. An excellent account of trial,where all the actual evidence was presented, was given in Albert J. Beveridge's Life of Marshall and you find can the various theories in biographies of Burr. He traveled through the old southwest talking to people--Andrew Jackson, Henry Clay and others, presumably trying to drum up support for whatever he had in mind, but no one wanted to talk about their conversations with him. I haven't looked at this material for a while but my recollection is that Burr was looking for an opening for a military leader, didn't have anything specific in mind and never formed a specific plan, Jackson, Clay et al. wanted nothing to do with him.
Not an expert, but have always been fascinated by the involvement of Colonel Morgan, as I grew up beside the property Morganza outside of Pittsburgh. This site has the entire trial of Aaron Burr listed and may be a good resource for you to peruse through - every witness and motion is recorded here from the trial:
http://law2.umkc.edu/faculty/projects/ftrials/burr/burrtrial.html