QUIETLY, behind the scenes, the Clinton Administration is preparing for the biggest regulatory crackdown of recent years. Attorney General Janet Reno is linking up with banking regulators and with HUD Secretary Henry Cisneros to end the supposed epidemic of discrimination against minorities in making home loans. The implications for society at large are ominous. Here, as in affirmative-action efforts in hiring, college admissions, and the drawing of voting districts, the Washington establishment is obsessed with "disparate impact," which it equates with racism. In the mortgage-lending area, there is ample evidence of disparate impact to feed this obsession. Data collected by...