When the European immigration began after the War of 1812, the country was in great need of labor. A hundred year later, the need was still there, but greatly diminished by the closing of the Frontier. The Immigration laws of the '20s, which after the Chinese Exclusion Act, was the first formal effort to limit immigration, were enacted after the post-war depression, and helped keep jobs open for demobilized war veterans but also for the
farmers displaced by th sudden collapse of commodity prices after France, for one began to get its fields back into production. The boom of the mid
20s caused a quick growth of the middle-class in the USA and this was caused by the general rise in wages. Immigration generally falls in Hard Times, but the limited immigration mitigated competition for scarce jobs after 1929. In general, immigration policy ought to focus on the needs of the country rather than some abstract principle of social justice. Furthermore, there should be no line jumping. People applying to immigration find it hard to get into the country because illegals have rushed into to fill so many jobs that there is little political pressure to ease legal restrictions.