The trial of Burr for treason occurred in Richmond, Virginia, a “sleepy little town [that] became the cynosure of all eyes.”  The courtroom could not hold the crowds, forcing Marshall to move the trial to the House of Delegates, a larger space, and among those in town were Andrew Jackson, a young Washington Irving as a journalist, and Winfield Scott.  The first opinion issued by Marshall concerned precisely with what charge or charges should Burr be held accountable and detained before a grand jury heard the case for indictment. One aspect of this was a potentially damaging letter produced through Wilkinson, but was not the original copy. Though Marshall stipulated that the evidence needed to commit Burr did not have to be as stringent as that which might produce an indictment or conviction, he discussed at length the problems surrounding the authenticity and accuracy of the letter before committing Burr for violation of the Neutrality Act, or “setting on foot and providing the means for an expedition against the territories of a nation at peace with the U.S.,” but not for treason.  
This small victory for Burr was compounded by a statement by Marshall that seemed directed at Jefferson in particular, that “the hand of malignity may [not] grasp any individual against whom its hate may be directed, or whom it may capriciously seize, charge him with some secret crime, and put him on the proof of his innocence.”  This, though forcefully worded, elicits Marshall’s underlying principal that the prosecution, particularly Jefferson, was running roughshod over individual rights and acting counter to the spirit and text of law. It also marks the beginning of Marshall’s consistent judgments that the charges must be proven in the context of the law, not merely in public perception. After striking this blow against Jefferson, Marshall committed what might be seen as an ethical blunder. Invited to a dinner by John Wickham, a lawyer on Burr’s counsel, Marshall arrived, stayed, and dined although Aaron Burr himself was also in attendance. The press discovered this and publicized it, and the trial that “was already political…became hopelessly so. Everything Marshall did from now on would be under a cloud.”  Though still before a grand jury even indicted Burr, passions on all sides were roused.
A letter from Burr to his daughter, Theodosia, describes both the general atmosphere as well as one early point of contention in the trial, the makeup and prejudice of the grand jury:
The grand jury is composed of twenty democrats and four federalists. Among the former is W.C. Nicholas, my vindictive and avowed enemy- the most so that could be found in this state (Virginia). The most indefatigable industry is used by the agents of government, and they have money at command without stint. If I were possessed of the same means, I could not only foil the prosecutors, but render them ridiculous and infamous. The democratic papers teem with abuse against me and my counsel, and even against the chief justice. 