Final answer:
War can ruin the prosperity of nations through the economic burden of maintaining an army with contributions from the people and the inflation caused by the proximity of an army, both of which lead to the impoverishment of the populace.
Step-by-step explanation:
According to John C. Calhoun, war can ruin the prosperity of nations by causing economic strain and rising costs that lead to impoverishment. Firstly, he notes that war necessitates the maintenance of an army which is often supported by contributions from a distance, as seen in the passage: 'Poverty of the State exchequer causes an army to be maintained by contributions from a distance.' This contribution leads to the impoverishment of the people.
Secondly, Calhoun points out that the proximity of an army causes inflation, leading to high prices which drain the people's substance, as described in the statement: 'the proximity of an army causes prices to go up; and high prices cause the people’s substance to be drained.' These factors show how warfare can seriously disrupt the economic stability of a region and deplete its resources.