It's not what you think:
By the 1960s, the systematic selection for competence came into direct conflict with the political imperatives of the civil rights movement. During the period from 1961 to 1972, a series of Supreme Court rulings, executive orders, and laws—most critically, the Civil Rights Act of 1964—put meritocracy and the new political imperative of protected-group diversity on a collision course. Administrative law judges have accepted statistically observable disparities in outcomes between groups as prima facie evidence of illegal discrimination. The result has been clear: any time meritocracy and diversity come into direct conflict, diversity must take priority.
The resulting norms have steadily eroded institutional competency, causing America’s complex systems to fail with increasing regularity. In the language of a systems theorist, by decreasing the competency of the actors within the system, formerly stable systems have begun to experience normal accidents at a rate that is faster than the system can adapt. The prognosis is harsh but clear: either selection for competence will return or America will experience devolution to more primitive forms of civilization and loss of geopolitical power.
Read the whole story over there (WARNING: long)