When defining the term citizen, the Sovereign Citizen often refers to 26 USC 3121 while totally avoiding the relevant statute 8 USC 1401. This mistake was most famously made in Rowe v IRS, Dist. Court, D. Maine 2006
Note that 26 USC 3121 states clearly that the definitions are ‘for the purpose of this chapter’
(e) State, United States, and citizenFor purposes of this chapter—
The term “United States” when used in a geographical sense includes the Commonwealth of Puerto Rico, the Virgin Islands, Guam, and American Samoa.
8 USC 1401 explains
The following shall be nationals and citizens of the United States at birth:(a) a person born in the United States, and subject to the jurisdiction thereof;
“All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”