http://www.creators.com/conservative/thomas-sowell/minimum-wage-madness-part-ii.html
...In the United States, the last year in which the black unemployment rate was lower than the white unemployment rate — 1930 — was also the last year when there was no federal minimum wage law. Inflation in the 1940s raised the pay of even unskilled workers above the minimum wage set in 1938. Economically, it was the same as if there were no minimum wage law by the late 1940s.
In 1948 the unemployment rate of black 16-year-old and 17-year-old males was 9.4 percent. This was a fraction of what it would become in even the most prosperous years from 1958 on, as the minimum wage was raised repeatedly to keep up with inflation....
...In South Africa during the era of apartheid, white labor unions urged that a minimum wage law be applied to all races, to keep black workers from taking jobs away from white unionized workers by working for less than the union pay scale.
Some supporters of the first federal minimum wage law in the United States — the Davis-Bacon Act of 1931 — used exactly the same rationale, citing the fact that Southern construction companies, using non-union black workers, were able to come north and under-bid construction companies using unionized white labor...
Excellent history lesson.