Vattel, who ranks among the first of authors, and whose work on the law of nations is recognized by every enlightened jurist throughout the civilized world, defines "war to be that state, where a nation prosecutes its rights by force." That this is a nation no one will doubt; that it is prosecuting its rights can not be denied; and no one will doubt that it is using force upon a stupendous scale--requiring four hundred millions of dollars, and 500,000 men, with the probability of additional requisitions of men and treasure for a successful termination of this fratricidal war. It may be said that this is a civil war. Admitting it to be so, the only distinction between this and an international war is, that the former is an intestinal war between the people, where the Republic is divided into two factions, and the latter is where two nations are opposed to each other. All the rules of civilized war, therefore, should govern equally, and it is to soften and mitigate the horrors of civil war that an exchange of prisoners is recognized. I have endeavored to show that the prisoners at the bar are not guilty of piracy, as defined by the Acts of Congress; and if they are not guilty of municipal piracy, they are certainly not guilty of piracy by the law of nations. What is a pirate? He is defined to be an enemy of the human race--a common sea rover, without any fixed place of residence, who acknowledges no sovereign, no law, and supports himself by pillage and depredation. Do the prisoners come within the meaning of this definition? Did they not encounter a British vessel upon the high seas? Could they not have captured her? But, no, gentlemen of the Jury, as soon as they ascertained that she belonged to a nation in amity with theirs, they allowed her to depart in peace. With the permission of the Court, I would beg leave to refer to an authority entitled to high respect--the works of Sir Leoline Jenkins, 4th Institutes, p. 154, where this principle is laid down: "If the subjects of different States commit robbery upon each other upon the high seas, if their respective States be in amity, it is piracy; if at enmity, it is not, for it is a general rule that enemies never can commit piracy on each other, their depredations being deemed mere acts of hostility." The prisoners were acting in good faith, by virtue of a commission under the seal of the Confederate States. It is said, by the learned counsel for the prosecution, that the prisoners were acting under the authority of a person named Jefferson Davis. This does so appear nominally, but it is virtually and actually a commission issuing from eight millions of people, who recognize and sanction it under the hand of their President and the seal of their Government--each one being _particeps criminis_, and each one being amenable to the laws of the country, and liable to the penalties of treason and piracy, if evenhanded justice is to be meted out.