About

https://iwtas.com/services/foreign-trusts-estate-gifts-tax/ United States (U.S.) system of federal income taxation is a citizenship-based income tax. Elsewhere in the world, the basic rule is that taxes are based on residency and not on taxation of worldwide income based on citizenship.
The origin of the U.S. taxation of worldwide income is the first federal U.S. income tax. Enacted in 1861 in the early months of the American Civil War, it was part of the Revenue Act of 1861. https://iwtas.com/services/your-fatca-guide/ levied a 3% tax on incomes over $800, but a 5% tax on income earned in the U.S. by, “any citizen of the United States residing abroad”.

The purpose was to prevent the U.S. wealthy from evading their tax obligations (military and civic) as American citizens and