Harold Robertson:

In the first decades of the twentieth century, the idea that individuals should be systematically evaluated and selected based on their ability rather than wealth, class, or political connections, led to significant changes in selection techniques at all levels of American society. The Scholastic Aptitude Test (SAT) revolutionized college admissions by allowing elite universities to find and recruit talented students from beyond the boarding schools of New England. Following the adoption of the SAT, aptitude tests such as Wonderlic (1936), Graduate Record Examination (1936), Army General Classification Test (1941), and Law School Admission Test (1948) swept the United States. Spurred on by the demands of two world wars, this system of institutional management electrified the Tennessee Valley, created the first atom bomb, invented the transistor, and put a man on the moon. 

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.