Professors Lesley Wexler and Suja Thomas joined a group of employment discrimination law professors in filing an amicus brief at the Supreme Court in support of the respondents in Comcast Corporation v. National Association of African American-Owned Media, et al. 

The summary of the argument in the brief is as follows:

"This Court should not interpret section 1981 to require proof of but-for causation, given that statute’s text, history, and purpose. Although Comcast invokes the canon of statutory construction that Congress intends statutory terms to have their settled common-law meaning, that canon does not apply here. Section 1981 has no statutory text that reflects a common-law understanding of causation. Indeed, in 1866, when Congress enacted the predecessor to section 1981, there was no well-settled common law of tort at all. Rather, just as courts have read 42 U.S.C. § 1982, which shares common text, history and purpose, this Court should read section 1981 to require plaintiffs alleging race discrimination to prove that Comcast was motivated at least in part by race.

"Moreover, even if Congress had intended section 1981 to incorporate tort law’s evolving understanding of factual causation, that common-law doctrine includes not only but-for cause, but a bundle of causal standards that are appropriate in different cases. Thus, to approximate the common law, this Court could choose two options: (1) apply but-for cause along with all of its supporting causal doctrines, including those which apply in cases with multiple, sufficient causes of an injury, or (2) apply a motivating factor standard, an approach that mitigates the limitations of but-for cause through a single standard.

"Even if this Court were to interpret section 1981 to require showing only but-for cause, it should make clear that but-for cause is not “sole” cause. That is, in this context, but-for cause simply requires a plaintiff to prove that race is one of the causes for an injury, even if there were also other causes. Accordingly, in most cases, it is not appropriate to dismiss section 1981 claims at the pleading stage on causation grounds."

Read the full brief.