In commencing hostilities against any other power, we must evidently take into consideration all the political and physical circumstances of the people with whom we are to contend:  we must regard their general character for courage and love of country; their attachment to their government and political institutions; the character of their rulers and their generals; the numbers, organization, and discipline of their armies; and particularly the relations between the civil and military authorities in the state, for if the latter be made entirely subordinate, we may very safely calculate on erroneous combinations.  We must also regard their passive means of resistance, such as their system of fortifications, their military materials and munitions, their statistics of agriculture, commerce, and manufactures, and especially the geographical position and physical features of their country.  No government can neglect, with impunity, these considerations in its preparations for war, or in its manner of conducting military operations.

Napoleon’s system of carrying on war against the weak, effeminate, and disorganized Italians required many modifications when directed against the great military power of Russia.  Moreover, the combinations of Eylau and Friedland were inapplicable to the contest with the maddened guerrillas of Minos, animated by the combined passions of hatred, patriotism, and religious enthusiasm.

Military power may be regarded either as absolute or relative:  the absolute force of a state depending on the number of its inhabitants and the extent of its revenues; the relative force, on its geographical and political position, the character of its people, and the nature of its government.  Its military preparations should evidently be in proportion to its resources.  Wealth constitutes both the apprehension and the incentive to invasion.  Where two or more states have equal means of war, with incentives very unequal, an equilibrium cannot exist; for danger and temptation are no longer opposed to each other.  The preparation of states may, therefore, be equal without being equivalent, and the smaller of the two may be most liable to be drawn into a war without the means of sustaining it.

The numerical relation between the entire population of a state, and the armed forces which it can maintain, must evidently vary with the wealth and pursuits of the people.  Adam Smith thinks that a country purely agricultural may, at certain seasons, furnish for war one-fifth, or even in case of necessity one-fourth, of its entire population.  A commercial or manufacturing country would be unable to furnish any thing like so numerous a military force.  On this account small agricultural states are sometimes able to bring into the field much larger armies than their more powerful neighbors.  During the Seven Years’ War, Frederick supported an army equal to one-twentieth of the entire Prussian population, and at the close of this memorable contest one-sixth of the males capable of bearing arms had actually perished on the field of battle.