When Congress have exerted their power by declaring war against a foreign nation, it is the duty of the President to prosecute it.  The Constitution has prescribed no particular mode in which he shall perform this duty.  The manner of conducting the war is not defined by the Constitution.  The term war used in that instrument has a well-understood meaning among nations.  That meaning is derived from the laws of nations, a code which is recognized by all civilized powers as being obligatory in a state of war.  The power is derived from the Constitution and the manner of exercising it is regulated by the laws of nations.  When Congress have declared war, they in effect make it the duty of the President in prosecuting it, by land and sea, to resort to all the modes and to exercise all the powers and rights which other nations at war possess.  He is invested with the same power in this respect as if he were personally present commanding our fleets by sea or our armies by land.  He may conduct the war by issuing orders for fighting battles, besieging and capturing cities, conquering and holding the provinces of the enemy, or by capturing his vessels and other property on the high seas.  But these are not the only modes of prosecuting war which are recognized by the laws of nations and to which he is authorized to resort.  The levy of contributions on the enemy is a right of war well established and universally acknowledged among nations, and one which every belligerent possessing the ability may properly exercise.  The most approved writers on public law admit and vindicate this right as consonant with reason, justice, and humanity.

No principle is better established than that—­

We have a right to deprive our enemy of his possessions, of everything which may augment his strength and enable him to make war.  This everyone endeavors to accomplish in the manner most suitable to him.  Whenever we have an opportunity we seize on the enemy’s property and convert it to our own use, and thus, besides diminishing the enemy’s power, we augment our own and obtain at least a partial indemnification or equivalent, either for what constitutes the subject of the war or for the expenses and losses incurred in its prosecution.  In a word, we do ourselves justice.

  “Instead of the custom of pillaging the open country and defenseless
  places,” the levy of contributions has been “substituted.”

Whoever carries on a just war has a right to make the enemy’s country contribute to the support of his army and toward defraying all the charges of the war.  Thus he obtains a part of what is due to him, and the enemy’s subjects, by consenting to pay the sum demanded, have their property secured from pillage and the country is preserved.

These principles, it is believed, are uncontroverted by any civilized nation in modern times.  The public law of nations, by which they are recognized,