HKB
We never find that a State joining in the cause of another State, takes it up with the same earnestness as its own. An auxiliary army of moderate strength is sent; if it is not successful, then the ally looks upon the affair as in a manner ended, and tries to get out of it on the cheapest terms possible.
In European politics it has been usual for States to pledge themselves to mutual assistance by an alliance offensive and defensive, not so far that the one takes part in the interests and quarrels of the other, but only so far as to promise one another beforehand the assistance of a fixed, generally very moderate, contingent of troops, without regard to the object of the war, or the scale on which it is about to be carried on by the principals. In a treaty of alliance of this kind, the ally does not look upon himself as engaged with the enemy in a war properly speaking, which should necessarily begin with a declaration of war, and end with a treaty of peace. Still, this idea also is nowhere fixed with any distinctness, and usage varies one way and another.
The thing would have a kind of consistency, and it would be less embarrassing to the theory of war if this promised contingent of ten, twenty, or thirty thousand men was handed over entirely to the state engaged in war, so that it could be used as required; it might then be regarded as a subsidised force. But the usual practice is widely different. Generally the auxiliary force has its own commander, who depends only on his own government, and to whom they prescribe an object such as best suits the shilly-shally measures they have in view.
But even if two States go to war with a third, they do not always both look in like measure upon this common enemy as one that they must destroy or be destroyed by themselves, the business is often settled like a commercial transaction; each, according to the amount of the risk he incurs or the advantage to be expected, takes shares in the concern to the extent of 30,000 or 40,000 men, and acts as if he could not lose more than the amount of his investment.
Not only is this the point of view taken when a State comes to the assistance of another in a cause in which it has in a manner, little concern, but even when both allies have a common and very considerable interest at stake, nothing can be done except under diplomatic reservation, and the contracting parties usually only agree to furnish a small stipulated contingent, in order to employ the rest of the forces according to the special ends to which policy may happen to lead them.
This way of regarding wars entered into by reason of alliances was quite general, and was only obliged to give place to the natural way in quite modern times, when the extremity of danger drove men’s minds into the natural direction (as in the wars against Buonaparte), and when the most boundless power compelled them to it (as under Buonaparte). It was an abnormal thing, an anomaly, for war and peace are ideas which in their foundation can have no gradations; nevertheless it was no mere diplomatic offspring which the reason could look down upon, but deeply rooted in the natural limitedness and weakness of human nature.
Lastly, even in wars carried on without allies, the political cause of a war has a great influence on the method in which it is conducted.