There are other incidental powers, belonging to the executive department, which are necessarily implied from the nature of the functions, which are confided to it. Among these, must necessarily be included the power to perform them, without any obstruction or impediment whatsoever. The president cannot, therefore, be liable to arrest, imprisonment, or detention, while he is in the discharge of the duties of his office; and for this purpose his person must be deemed, in civil cases at least, to possess an official inviolability. In the exercise of his political powers he is to use his own discretion, and is accountable only to his country, and to his own conscience. His decision, in relation to these powers, is subject to no control; and his discretion, when exercised, is conclusive.
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