WASHINGTON -- Like pebbles tossed into ponds, important Supreme Court rulings radiate ripples of consequences. Consider a 1971 Supreme Court decision that supposedly applied but actually altered the 1964 Civil Rights Act. During debate on the act, prescient critics worried that it might be construed to forbid giving prospective employees tests that might produce what was later called, in the 1971 case, a "disparate impact" on certain preferred minorities. To assuage these critics, the final act stipulated that employers could use "professionally developed ability tests" that were not "designed, intended or used to discriminate." Furthermore, two Senate sponsors of the...