"If a U.S. company designs products in one country, manufactures them in another country, and sells them in a third, in which jurisdiction should the company pay tax? The country in which it's domiciled?"
Why, none of the above. Taxes should be on consumption or cost-recovery basis or something ... Oh, but you don't mean "should, according to fche", but "should, according to law". Why, then the Double Irish is perfectly right. Oh, but you don't mean "should, according to law", but "should, according to macsimon". Well, then obviously they should pay 100% of their net income as tax, because that's fair.