This article describes the argumentative structure of Hayek on the relationship between power to tax and the progressive tax. It is observed throughout its work giving special attention to two works: The Constitution of Liberty (1959) and Law, Legislation and Liberty, vol3; The Political Order of Free People, 1979) Hayek describes one of the arguments most complete information about SFP progressive tax systems (progressive tax). According to the author the history of the tax progressive system, works against such a tax model and deploys a variety of arguments in his favorite spot by critics: liberal democracy.