Mises’s ultimate long-term solution to this problem was not the strict immigration controls which he later advocated as a temporary expedient after the War. Such barriers to labour mobility do nothing to reduce the gap in living standards between rich and poor—a gap he considered the root of the envy and rancour felt by the latter toward the former which would render unrestricted immigration so potentially dangerous. What Mises proposed as the only viable solution to the problem of the discrepancy between rich and poor nations was the universal adoption of the classical-liberal agenda of minimal government:
It is clear that no solution of the problem of immigration is possible if one adheres to the ideal of the interventionist state, which meddles in every field of human activity. Only the adoption of the liberal program could make the problem of immigration, which today seems insoluble, completely disappear.26
It was with the problem of relations between rich and poor firmly in mind that, toward the end of the book, he declared that
The greatest ideological question that mankind has ever faced . . . is the question of whether we shall succeed in creating throughout the world a frame of mind . . . [that] can be nothing less than the unqualified, unconditional acceptance of liberalism. Liberal thinking must permeate all nations, liberal principles must pervade all political institutions, if the prerequisites of peace are to be created and the causes of war eliminated.
In Mises’s view, for the U.S. or U.K. to remove all immigration barriers, as certain libertarians have recently advocated,28 even after such governments had first been minimized, would still not be enough to prevent the danger he foresaw attendant upon mass immigration into these countries by peoples of different culture and ethnicity from that of majority. According to Mises, even policing and the judicial process are capable of being turned against minorities by members of majorities who perceive the minorities as alien and foreign. As Mises put it,
Large areas of the world have been settled, not by the members of just one nationality, one race, or one religion, but by a motley mixture of many peoples. As a result of the migratory movements that necessarily follow shifts in the location of production, more new territories are continually being confronted with the problem of a mixed population To be a member of a national minority always means that one is a second class citizen The citizen who speaks a foreign tongue … must obey the law; yet he has a feeling that he is excluded from effective participation in shaping the will of the legislative authority or at least that he is not allowed to cooperate in shaping it to the same extent as those whose native tongue is that of the ruling majority. And when he appears before a magistrate or any administrative official as a party to a suit or petition, he stands before men whose political thought is foreign to him because it developed under different ideological influences. [T]he very fact that the members of the minority are required… to make use of a language foreign to them already handicaps them, seriously in many respects … when … on trial…. At every turn, the member of a national minority is made to feel that he lives among strangers and that he is, even if the letter of the law denies it, a second-class citizen….
All these disadvantages are felt to be very oppressive even in a state with a liberal constitution in which the activity of the government is restricted to the protection of the life and property of the citizens. But they become intolerable in an interventionist or a socialist state.29