§1. Wars are offensive and defensive. The use of force to obtain justice for injuries done, is _offensive war_. The making use of force against any power that attacks a nation or its privileges, is _defensive war_. A war may be defensive in its principles, though offensive in its operation. For example: one nation is preparing to invade another; but before the threatened invasion takes place, the latter attacks the former as the best mode of repelling the invasion. In this case, the party making the attack acts on the _defensive_. (§10.) The contending parties are called _belligerents_. The word _belligerent_ is from the Latin _bellum_, war, and _gero_, to wage or carry on. Nations that take no part in the contest, are called _neutrals_.
§2. War ought never to be undertaken without the most cogent reasons. In the first place, there must be a _right_ to make war, and _just grounds_ for making it. Nations have no right to employ force any further than is necessary for their own defense, and for the maintenance of their rights. Secondly, it should be made from _proper motives_, the good of the state, and the safety and common advantage of the citizens. Hence, there may be, according to the law of nations, just cause of war, when it would be inexpedient to involve the nation in such a calamity.
§3. The numerous objects of a lawful war may be reduced to these three: (1.) To recover what belongs to us, or to obtain satisfaction for injuries. (2.) To provide for our future safety by punishing the offender. (3.) To defend or protect ourselves from injury by repelling unjust attacks. The first and second are objects of an _offensive_ war; the third is that of a _defensive_ war.
§4. Injury to an individual citizen of a state, by the subjects of another state, is deemed a just cause of war, if the persons offending, or the government of the state to which they belong, do not make reparation for the injury; for every nation is responsible for the good behavior of its subjects. But, although this would, according to the law of nations, afford justifiable cause of war, neither the honor nor the true interest of a nation requires that war should always be made for so slight a cause.