The main argument for free trade was the international division of labor, but “freedom of migration does not exist, has never existed and probably never will exist.” It would not be desirable even if it were possible. The Ruhr Valley would become unbelievably crowded, and the Alps would empty out entirely: “One need not be a nationalist for such things to be undesirable.” Haberler proposed that he could prove that “free trade is beneficial for all even when there is no freedom of migration and the peoples remain firmly rooted in their countries.”
