In United States v. Trenton Potteries Co., 273 U.S. 392 (1927), defendants, who controlled 82 per cent of the business of manufacturing and distributing vitreous pottery in the United States, had combined to fix prices. It was found that they had the power to do this and had exerted it. The defense that the prices were reasonable (Cost Justification) was overruled, as the court held that the power to fix prices involved "power to control the market and to fix arbitrary and unreasonable prices," and that in such a case the difference between legal and illegal conduct could not "depend upon so uncertain a test" as whether the prices actually fixed were reasonable, - a determination which could "be satisfactorily made only after a complete survey of our economic organization and a choice between rival philosophies." See United States v. Cohen Grocery Co., 255 U.S. 81 (1921).