Another early protester was Arthur J. Porth, who argued that the Sixteenth Amendment to the U.S. Constitution should itself be declared unconstitutional, under his theory that the income taxes under the Internal Revenue Code of 1939 imposed "involuntary servitude" in violation of the Thirteenth Amendment. That argument was ruled to be without merit in "Porth v. Brodrick, United States Collector of Internal Revenue for the State of Kansas". He continued his tax protester activities and was eventually convicted of willful failure to file returns and other tax crimes; see "United States v. Porth".