Sec.10.  When the alliance is defensive, the treaty binds each party to assist the other only when engaged in a defensive war, and unjustly attacked.  By the conventional law of nations, the government that first declares, or actually begins the war, is considered as making offensive war; and though it should not be the first actually to apply force, yet if it first renders the application of force necessary, it is the aggressor; and the other party, though the first to apply force, is engaged in a defensive war. (Sec.1.)

Chapter LXVI.

Declaration of War; its Effect upon the Person and Property of the Enemy’s subjects; Stratagems in War; Privateering.

Sec.1.  When a nation has resolved on making war, it is usual to announce the fact by a public declaration.  In monarchical governments, the power to declare war, which of course includes the right of determining the question whether it shall be made, is vested in the king.  In the United States, this power is, by the constitution, given to the representatives of the people, for reasons elsewhere stated. (Chap.  XXXVI, Sec.3.)

Sec.2.  It was usual, formerly, to communicate a declaration of war to the enemy.  According to modern practice, a formal declaration to the enemy is not required.  Any manifesto or paper from an official source, announcing that the country is in a state of war, is considered sufficient.  The recalling of a minister has alone been regarded as a hostile act, and followed by war, without any other declaration.  But such cases have not been frequent.  Under ordinary circumstances, the recall of a minister is not an offensive act.

Sec.3.  The government of a state acts for and in behalf of all its citizens; and its acts are binding upon all.  Hence, when war is declared, it is not merely a war between the two governments; all the subjects of the government declaring it become enemies to all the subjects of that against which it is declared.

Sec.4.  Whether, on the occurrence of a war in any state, the subjects of the enemy found within the state may be detained as prisoners of war, and their movable property confiscated; or whether they are entitled to a reasonable time to retire with their effects, is a question upon which writers of public law are not agreed.  Few civilized nations, at the present day, would deny such persons a reasonable time to retire with their property.  Of houses and lands, all admit that only the income is subject to confiscation.  The privilege spoken of, instead of being left to uncertainty, is now, with great propriety, generally secured by treaty.

Sec.5.  When war is declared, all intercourse between the two countries at once ceases.  All trade between the citizens, directly or indirectly, is strictly forbidden; and all contracts with the enemy made during the war are void.

Sec.6.  Although a state of war makes all the subjects of one nation enemies of all those of the other, they cannot lawfully engage in offensive hostilities without permission of their government.  If they have no written commission as evidence of such permission, and if they should be taken by the enemy, they would not be entitled to the usual mild treatment which other prisoners of war receive, but might be treated without mercy as lawless robbers and banditti.