“2d. That if this construction be erroneous, no testimony can be received to charge one man with the overt acts of others until those overt acts, as laid in the indictment, be proved to the satisfaction of the court. “The question which arises on the construction of the constitution, in every point of view in which it can be contemplated, is of infinite moment to the people of this country and to their government, and requires the most temperate and the most deliberate consideration. “Treason against the United States shall consist only in levying war against them.” The Chief Justice then proceeds to elaborately discuss an overt act of levying war. The opinion delivered by the Supreme Court in the case of Bollman and Swartout was declared by him to be not correctly understood; and that there must be, before an overt act of treason is completed, either the actual employment of force or a military assemblage of men, who are in a posture of war. In conclusion the Chief Justice said: “The law of the case being thus far settled; what ought to be the decision of the court on the present motion? Ought the court to sit and hear testimony which cannot affect the prisoner? or ought the court to arrest that testimony? On this question much has been said: much that may perhaps be ascribed to a misconception of the point really under consideration. The motion has been treated as a motion confessedly made to stop relevant testimony; and, in the course of the argument, it has been repeatedly stated, by those who oppose the motion, that irrelevant testimony may and ought to be stopped. That this statement is perfectly correct is one of those fundamental principles in judicial proceedings which is acknowledged by all, and is founded in the absolute necessity of the thing. No person will contend that, in a civil or criminal case, either party is at liberty to introduce what testimony he pleases, legal or illegal, and to consume the whole term in details of facts unconnected with the particular case. Some tribunal then must decide on the admissibility of testimony. The parties cannot constitute this tribunal; for they do not agree. The jury cannot constitute it; for the question is whether they shall hear the testimony or not. Who then but the court can constitute it? It is of necessity the peculiar province of the court to judge of the admissibility of testimony. If the court admit improper or reject proper testimony, it is an error of judgment; but it is an error committed in the direct exercise of their judicial functions.