Tax protester arguments are arguments made by people, primarily in the United States, who contend that tax laws are unconstitutional or otherwise invalid.
Tax protester arguments are typically based on an asserted belief that their government is acting outside of its legal authority when imposing such taxes. The label "tax protester" should be distinguished from "tax resister", an individual who refuses to pay tax on moral rather than legal grounds.
In the United States, tax protester arguments are generally directed to the U.S. federal income tax.
Arguments made by tax protesters generally deal with the U.S. federal income tax and not with other taxes such as the gift tax, estate tax, sales tax, and property tax (although some tax protesters have attacked the last category under allodial title claims).
Some tax protesters may cite what they believe is evidence that the Sixteenth Amendment to the Constitution (removing any apportionment requirement for income taxes) was never "properly ratified" or that it was properly ratified but does not permit the taxation of individual income, or particular forms of individual income. One argument is based on the contention that the legislatures of various states passed bills of ratification with different capitalization, spelling of words, or punctuation marks (e.g., semi-colons instead of commas) (see, e.g., United States v. Thomas). Another argument made by some tax protesters is that because the United States Congress did not pass an official proclamation recognizing Ohio's 1803 admission to statehood until 1953 (see Ohio Constitution), Ohio was not a state until 1953 and therefore the Sixteenth Amendment was not properly ratified (see Ivey v. United States and Knoblauch v. Commissioner in the referenced article). Another tax protester argument is that the manner in which the income tax is enforced violates the Fifth Amendment, which protects individuals from having to make self-incriminating statements. In particular, they argue that the Fifth Amendment protects individuals from being required to file a personal income tax return. This argument was ruled invalid by the United States Supreme Court in the case of United States v. Sullivan.