After the war ended there was concern about jobs for the returning troops by the millions from the war in Europe. Joblessness had increased under Harry Truman to the point that his popularity dropped to 22% by 1951. Truman's Commission for Miratory Labor pointed out that immigration was causing social ills and increasing joblessness in the southwest. When Eisenhower was elected in 1952 there was opposition from unions in addition to small farms to migratory labor. In 1954 Operation Wetback was launched to return 1 million migrants back to Mexico.
Note that throughout 1910 to 1950 the US completely restricted Chinese, Indian, and Asian migration to America, even though the Chinese labor helped build the transcontinental railroad.
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