Paradoxically, the cotton gin, a labor-saving device, helped preserve and prolong slavery in the United States for another 70 years. Before the 1790s, slave labor was primarily employed in growing rice, tobacco, and indigo, none of which were especially profitable anymore. Neither was cotton, due to the difficulty of seed removal. But with the invention of the gin, growing cotton with slave labor became highly profitable – the chief source of wealth in the American South, and the basis of frontier settlement from Georgia to Texas. "King Cotton" became a dominant economic force, and slavery was sustained as a key institution of Southern society.