Comment Non-resident taxes (Score 2, Insightful) 210
The US is almost unique in requiring non-resident citizens to pay income tax on their earnings (above a threshold of about $110,000). There are certain other provisions for non-residents to avoid double taxation, but it all gets pretty complex and you can understand why some wealthy Americans who can take out citizenship in their country of residence decide that it's easier to just renounce their US citizenship.