The uniquely American definition of “tax residency,” which includes the imposition of worldwide taxation on the tax residents of other countries who happen to be American (even if they don't realize it), has left the U.S. Internal Revenue Service in charge of overseeing the implementation of three separate and distinct tax systems: residence, source, and extraterritorial, according to Paris-based attorney and U.S. taxpayer rights campaigner Laura Snyder, Toronto-based U.S. citizenship lawyer John Richardson, and Australia-based, recently-retired university lecturer and FixtheTaxTreaty.org founder Karen Alpert...