Another topic respecting war， which it is of importance to consider in this place， relates to the mode of conducting it. Upon this article， our judgement will be greatly facilitated by a recollection of the principles already established， first， that no war is justifiable but a war purely defensive； and secondly， that a war already begun is liable to change its character in this respect， the moment the object pursued in it becomes in any degree varied. From these principles it follows as a direct corollary that it is never allowable to make an expedition into the provinces of the enemy， unless for the purpose of assisting its oppressed inhabitants.
It is scarcely necessary to add that all false casuistry respecting the application of this exception would be particularly odious； and that it is better undisguisedly to avow the corrupt principles of policy by which we conduct ourselves than hypocritically to claim the praise of better principles， which we fail not to wrest to the justification of whatever we desire. The case of relieving the inhabitants of our enemy's territory， and their desire of obtaining relief， ought to be unequivocal； we shall be in great danger of misapprehension on the subject when the question comes under the form of immediate benefit to ourselves； and， above all， we must recollect that human blood is not to be shed upon a precarious experiment.
The occasional advantages of war that might be gained by offensive operations might be abundantly compensated by the character of magnanimous forbearance that a rigid adherence to defence would exhibit， and the effects that character would produce， both upon foreign nations， and upon our own people. Great unanimity at home can scarcely fail to be the effect of a direct and clear conformity to political justice. The enemy who penetrates into our country， wherever he meets a man will meet a foe. Every obstacle will oppose itself to his progress， while everything will be friendly and assisting to our own forces. He will scarcely be able to procure the slightest intelligence， or understand in any case his relative situation. The principles of defensive war are so simple as to procure an almost infallible success. Fortifications are a very equivocal species of protection， and will perhaps oftener be of advantage to the enemy， by being first taken， and then converted into magazines for his armies. A moving force on the contrary， if it only hovered about his march， and avoided general action， would always preserve the real superiority. The great engine of military success or miscarriage is the article of provisions； and the further the enemy advanced into our country， the more easy would it be to cut off his supply； at the same time that， so long as we avoided general action， any decisive success on his part would be impossible. These principles， if rigidly practiced， would soon be so well understood that the entering in a hostile manner the country of a neighbouring nation would come to be regarded as the infallible destruction of the invading army. Perhaps no people were ever conquered at their own doors， unless they were first betrayed， either by divisions among themselves， or by the abject degeneracy of their character. The more we come to understand of the nature of justice， the more it will show itself to be stronger than a host of foes. Men whose bosoms are truly pervaded with this principle cannot perhaps be other than invincible. Among the various examples of excellence， in almost every department， that ancient Greece has bequeathed us， the most conspicuous is her resistance with a handful of men against three millions of invaders.