100 years ago Jack London was convinced that future wars will not be possible, for the simple fact that they will be too costly for any population to sustain...
"This leads to the economic aspect of future warfare. The maintenance of modern armies means enormous expenditure of money. The expenditure of life would correspond should they be unwise enough to even venture partial attacks in isolated portions of the field. Therefore, the question arises: How long will the working populations which are represented by these armies be able and willing to feed them, to furnish them with the munitions of war, and to replete the ranks of the soldiers from the ranks of the producers? It is inevitable, supposing the home political situation to remain unchanged, that the nation with the greater and more available resources, coupled with the tougher and more tenacious population, will be the victor. Famine, not force, will decide the issue. [...]
The civil population will decide the future war by its capacity for enduring all the privations consequent upon a state of semi-famine when the whole industrial system is thrown out of joint, and by its power and willingness to fill the mouths of the million non-producing soldiers and to furnish them with the sinews of war. At the front will be the chess-game; at home the workers feeding the players. All will depend upon the stamina of the civil population.
In the event of such a war, securities, which are now held largely by the middle classes, would go tumbling and crashing, rending it difficult for the government to float loans on a disrupted and frightened market. The disastrous effect to-day of of a war rumor on any seat of exchange, is common knowledge. If paper money were issued under such conditions, its depreciation would be instant and great. The rise of the necessaries of life will tend to do this and to set into motion the remorseless pendulum of action and reaction. The countries in which more live by trade than by agriculture—the wheat-importing countries—will feel the pinch of famine quickly and bitterly. [...] The very fear of this, on the sensitive capitalistic system, even with danger afar off, is bound to make the market panicky and to send prices skyward. And under such circumstances speculation is sure to exact its exorbitant penalty. The ravages of the commercial crisis in time of peace are too well known to make necessary further comment on what they would be in time of war.
The interruption of the operation of the productive forces, and the difficulty in satisfying the vital needs of the population, lead up to the political aspect of future warfare. Are the peoples, especially of the European countries, homogeneous enough in their political beliefs to stand in the strain? Labor troubles, bread riots, and rebellion are factors, subversive all, which must be taken into account. The mobilization of a whole working population may lead to unpleasant results, conscription to revolution. There are strong tendencies threatening the present social order which cannot be lightly passed over. Also, a strong anti-military propaganda has grown up. The small protesting voices of the past have merged into the roar of the peoples. The world has lifted itself to a higher morality. The aim of the human is to alleviate the ills of the human. Among all classes the opposition to war is keen and growing."
Jack London, The Impossibility of War.