As Professor Richard Primus noted in his article, Equal Protection and Disparate Impact: Round Three, the constitutional issues surrounding the disparate impact theory of discrimination have evolved significantly over time. First the question was whether the Constitution’s equal protection guarantee embodied disparateimpact. Most people assumed yes, but the Supreme Court said no in 1976 in Washington v. Davis. Second, the source of Congress’ power to prohibit disparate impact discrimination was called into question with the so-called federalism revolution. Only if it was within Congress’ power under Section 5 of the Fourteenth Amendment could disparate impact legislation be applied to the states consistent with the Eleventh Amendment. Justice Scalia, concurring in Ricci v. DeStefano, goes one step further: to the extent that the prohibition on disparate impact discrimination requires employers to take race conscious action, can Congress enact it consistent with the Fifth Amendment’s guarantee of due process? This paper argues that the answer is "yes" after the cases of the federalism revolution and that Congress' power comes from the Fourteenth and Thirteenth Amendments. However the greatest dangers to disparate impact are the passage of time since the civil rights movement, the lack of consensus that disparate impact is discrimination, and the worldview by several of the Justices that discrimination against people of color and women is a thing of the past.
McCormick, Marcia L., Disparate Impact and Equal Protection after Ricci v. DeStefano (2012). Wisconsin Journal of Law, Gender & Society.