Tracing the pattern of executive and congressional actions in the twentieth century bears out the general point made by Joyce Vialet, an authority on the law and history of U.S. immigration, that "the distinction between immigrants and refugees, unheard of during the mass migrations of the 19th century, … developed in the wake of World War II, primarily as a means of reconciling our traditional ideal of asylum with restrictions in the immigration law." With the designation of the "Asiatic barred zone" in the 1917 act, tightened by the Johnson-Reed Act of 1924, the barriers to immigration from Asia and the Pacific were made virtually impregnable. In the 1920s the former "open door" was almost closed to Mediterranean Europe, the Balkans, Asia Minor, and the Black Sea region, where the "push" of poverty, often associated with the minority status and religious and ethnic persecution of disadvantaged groups (notably pogroms against Jews in czarist Russia), drove increasing millions toward the attractive "pull" of the United States during the three decades preceding World War I. (The Catholic Irish immigration of the 1840s–1850s was an earlier microcosm of similar economic, religious, and ethnic factors driving exiles to the United States.) This was the "new immigration" so distasteful to the older, established immigrant groups who in the 1960s would be dubbed the WASPS: White Anglo-Saxon Protestants.
After World War II, which had brought no real opening of the immigration door, those who once would have come to the United States as ordinary immigrants now could come in any numbers only as refugees. Likewise in the 1980s and 1990s, many poor, frightened, persecuted migrants—and the simply ambitious—came from Central America and the Caribbean to the United States seeking a better life, economically, politically, and socially. The great majority came legally as admitted immigrants, and others came as technical refugees; the "illegals" arrived surreptitiously without documentation, and the desperate appealed for formal asylum. Where once "Asian" race and then European "ethnicity" had been categories of exclusion, now family unification, employment skills, and even levels of social and personal threats and violence became the criteria for admission. Such has been the recent history of asylum in the much longer history of American immigration—a history of inclusion and exclusion that was encapsulated in the exhortation of Thomas Paine's Common Sense on the eve of American independence:
O ye that love mankind! Ye that dare oppose, not only the tyranny, but the tyrant, stand forth! Every spot of the old world is overrun with oppression. Freedom hath been hunted round the globe. Asia, and Africa, have long expelled her—Europe regards her like a stranger, and England hath given her warning to depart. O! receive the fugitive, and prepare in time an asylum for mankind.