The expression “to crack the whip” means: To be in control; to have absolute dominance; to have under one’s thumb; to rule the roost.
The Florida “cracker,” nowadays, tries to persuade himself and others that this nickname originated, not, as was actually the case, because his antecedents were notorious braggarts, i.e., cracked tall tales, but, as was not the case, because they were drovers, who cracked the whip over cattle or teams of oxen or mules.
Our present expression, however, did originate from the skill of drovers or teamsters in handling the vicious bullwhacker whip of, especially, the nineteenth century.
Before the days of the railroad, or to areas unreached by them, large wheeled wagons drawn by two, four, six or more pairs of horses, mules, or oxen carted freight over mountains and plains to ever-extending Western frontiers.
The whip or bullwhacker of the driver, though short-handled, carried a long heavy thong which, properly wielded, could be snapped through the air to sound like a shot from a gun.
Some drivers became so expert as, reputedly, to be able to kill a horsefly from the flanks of the leading horse without disturbing a hair of the animal, or to flick a piece of the hide from a lagging “critter.”
All these were the ones who, originally, “cracked the whip.”