Where no discipline is enforced in war a state of things results which resembles far more the… religious wars… than the regular wars of modern times. And such a state of things results speedily, too; for all growth, progress and rearing, moral or material, are slow; all destruction, relapse, and degeneracy fearfully rapid. It requires the power of the Almighty and a whole century to grow an oak tree; but only a pair of arms, an ax, and an hour or two to cut it down.
—Francis Lieber, Guerrilla Parties Considered with Reference to the Laws and Usages of War (1862)