S. Fred Singer claims that my first three cases (in which there are no foreign demanders) are hardly realistic because price discrimination is impossible. Singer is correct about the realism of these cases: foreign demanders, after all, do exist. Nevertheless these cases are important for understanding the impact of a variable import fee. The bottom line-which Singer does not apparently dispute - is that if foreign oil producers have some degree of monopoly power, then a VIF will raise not only the price paid by domestic consumers but also the price charged by foreign producers.
