But that a man may be legally absent, who has counselled or procured a treasonable act, is proved by all those books which treat upon the subject; and which concur in declaring that such a person is a principal traitor, not because he was legally present, but because in treason all are principals. Yet the indictment, speaking upon general principles, would charge him according to the truth of the case....
If the conspirator had done nothing which amounted to levying of war, and if by our constitution the doctrine that an accessory becomes a principal be not adopted, in consequence of which the conspirator could not be condemned under an indictment stating the truth of the case, it would be going very far to say that this defect, if it be termed one, may be cured by an indictment stating the case untruly.
In point of law then, the man, who incites, aids, or procures a treasonable act, is not merely in consequence of that incitement, aid or procurement, legally present when that act is committed.
If it do not result, from the nature of the crime, that all who are concerned in it are legally present at every overt act, then each case depends upon its own circumstances; and to judge how far the circumstances of any case can make him legally present, who is in fact absent, the doctrine of constructive presence must be examined.
The whole treason laid in this indictment is the levying of war in Blennerhassett's island; and the whole question to which the inquiry of the court is now directed is whether the prisoner was legally present at that fact.
I say this is the whole question; because the prisoner can only be convicted on the overt act laid in the indictment. With respect to this prosecution, it is as if no other overt act existed.
If other overt acts can be inquired into, it is for the sole purpose of proving the particular fact charged. It is as evidence of the crime consisting of this particular fact, not as establishing the general crime by a distinct fact.
The counsel for the prosecution have charged those engaged in the defence with considering the overt act as the treason, whereas it ought to be considered solely as the evidence of the treason; but the counsel for the prosecution seem themselves not to have sufficiently adverted to this clear principle; that though the overt act may not be itself the treason, it is the sole act of that treason which can produce conviction. It is the sole point in issue between the parties. And the only division of that point, if the expression be allowed, which the court is now examining, is the constructive presence of the prisoner at the fact charged....