 If the FairTax bill were passed , permanent elimination of income taxation would not be guaranteed ; the FairTax bill would repeal much of the existing tax code , but the Sixteenth Amendment would remain in place . Preventing new legislation from reintroducing income taxation would require a repeal of the Sixteenth Amendment to the United States Constitution with a separate provision expressly prohibiting a federal income tax . This is referred to as an " aggressive repeal " . Separate income taxes enforced by individual states would be unaffected by the federal repeal . Passing the FairTax would require only a simple majority in each house of the United States Congress along with the signature of the President , whereas enactment of a constitutional amendment must be approved by two thirds of each house of the Congress , and three @-@ quarters of the individual U.S. states . It is therefore possible that passage of the FairTax bill would simply add another taxation system . If a new income tax bill were passed after the FairTax passage , a hybrid system could develop ; albeit , there is nothing preventing a bill for a hybrid system today . To address this issue and preclude that possibility , in the 111th Congress John Linder introduced a contingent sunset provision in H.R. 25 . It would require the repeal of the Sixteenth Amendment within 8 years after the implementation of the FairTax or , failing that , the FairTax would expire . Critics have also argued that a tax on state government consumption could be unconstitutional . 
