In 1964 the United States federal government began attempts to eliminate racial discrimination in employment and wages: the United States Congress enacted Title VII of the Civil Rights Act, prohibiting employers from making employment decisions on the basis of race. In 1965 President Johnson issued Executive Order 11,246, which prohibited discrimination by United States government contractors and emphasized direct monitoring of minority representation in contractors' work forces. Nonetheless, proponents of the "continuous change" hypothesis believe that United States federal law had a marginal impact on the economic progress made by black people in the United States between 1940 and 1975. Instead they emphasize slowly evolving historical forces, such as long-term trends in education that improved segregated schools for black students during the 1940s and were operative during and after the 1960s. They argue that as the quality of black schools improved relative to that of white schools, the earning potential of those attending black schools increased relative to the earning potential of those attending white schools. However, there is no direct evidence linking increased quality of underfunded segregated black schools to these improvements in earning potential. In fact, even the evidence on relative schooling quality is ambiguous. Although in the mid-1940s term length at black schools was approaching that in white schools, the rapid growth in another important measure of school quality, school expenditures, may be explained by increases in teachers' salaries, and historically, such increases have not necessarily increased school quality. Finally, black individuals in all age groups, even those who had been educated at segregated schools before the 1940s, experienced post-1960 increases in their earning potential. If improvements in the quality of schooling were an important determinant of increased returns, only those workers who could have benefited from enhanced school quality should have received higher returns. The relative improvement in the earning potential of educated black people of all age groups in the United States is more consistent with a decline in employment discrimination. An additional problem for continuity theorists is how to explain the rapid acceleration of black economic progress in the United States after 1964. Education alone cannot account for the rate of change. Rather, the coincidence of increased United States government antidiscrimination pressure in the mid-1960s with the acceleration in the rate of black economic progress beginning in 1965 argues against the continuity theorists' view. True, correlating federal intervention and the acceleration of black economic progress might be incorrect. One could argue that changing altitudes about employment discrimination sparked both the adoption of new federal policies and the rapid acceleration in black economic progress. Indeed, the shift in national attitude that made possible the enactment of Title VII was in part produced by the persistence of racial discrimination in the southern United States. However, the fact that the law had its greatest effect in the South, in spite of the vigorous resistance of many Southern leaders, suggests its importance for black economic progress.