The Wealth of Nations_ Books 4-5 - Adam Smith [185]
In a more advanced state of society, two different causes contribute to render it altogether impossible that they who take the field should maintain themselves at their own expense. Those two causes are, the progress of manufactures, and the improvement in the art of war.
Though a husbandman should be employed in an expedition, provided it begins after seed-time and ends before harvest, the interruption of his business will not always occasion any considerable diminution of his revenue. Without the intervention of his labour, nature does herself the greater part of the work which remains to be done. But the moment that an artificer, a smith, a carpenter, or a weaver, for example, quits his work-house, the sole source of his revenue is completely dried up. Nature does nothing for him, he does all for himself. When he takes the field, therefore, in defence of the public, as he has no revenue to maintain himself, he must necessarily be maintained by the public. But in a country of which a great part of the inhabitants are artificers and manufacturers, a great part of the people who go to war must be drawn from those classes, and must therefore be maintained by the public as long as they are employed in its service.
When the art of war, too, has gradually grown up to be a very intricate and complicated science, when the event of war ceases to be determined, as in the first ages of society, by a single irregular skirmish or battle, but when the contest is generally spun out through several different campaigns, each of which lasts during the greater part of the year, it becomes universally necessary that the public should maintain those who serve the public in war, at least while they are employed in that service. Whatever in time of peace might be the ordinary occupation of those who go to war, so very tedious and expensive a service would otherwise be by far too heavy a burden upon them. After the second Persian war, accordingly, the armies of Athens seem to have been generally composed of mercenary troops, consisting, indeed, partly of citizens, but partly too of foreigners, and all of them equally hired and paid at the expense of the state. From the time of the siege of Veii, the armies of Rome received pay for their service during the time which they remained in the field. Under the feudal governments the military service both of the great lords and of their immediate dependants was, after a certain period, universally exchanged for a payment in money, which was employed to maintain those who served in their stead.
The number of those who can go to war, in proportion to the whole number of the people, is necessarily much smaller in a civilised than in a rude state of society. In a civilised society, as the soldiers are