What is a legal taxpayer?

Legal taxpayers are those whom are within the exclusive jurisdiction of the National Government, this is only the District of Columbia and U.S. Territories. American Nationals [nonresident aliens] are considered legal non-taxpayers when born, if at any time they elected to join the tax club by filing a 1040 they have now elected to become legal taxpayers. Revenue laws 26 USC and 26 CFR. Revocation of election is key to exit US tax club. Expatriate.