"Nowadays, dynamite, TNT, and fuzes, as well as fire bombs, time clocks, knives, pistols, rifles, and tommy guns can turn an occupied country into a hell for its conquerors. These are the weapons of sabotage and, in broader terms, of guerrilla warfare. Old-time campaigners considered this form of internal Strife a rag-tag orphan of war, troublesome until quelled by firm measures. But, though military strategists have been slow to admit it, there are no longer any firm measures that will quell it. Even the torture and mass murder of civilians may multiply a conqueror’s underground enemies. Assuming an outside source of supply, the airplane, the cargo parachute, and the portable radio, twentieth-century guerrilla warfare can assume maddening dimensions."