Dan Mitchel explains cogently why US extra-territorial taxation penalizes American businesses and makes it impossible for them to compete on a level playing field with foreign companies.  He doesn’t even touch on the subject of why US international taxation of individual US citizens living outside the borders of the United States. This penalizes American companies for hiring US citizens overseas, not to  mention how it destroys the lives of US citizens abroad.  On that, read Roger Conklin.  Hat tip Isaac Brock Society.