Oral arguments in a major ­housing discrimination case before the U.S. Supreme Court on Jan. 21 left some advocates more optimistic than they expected to be that a broad interpretation of the Fair Housing Act will survive.

At stake in Texas Department of Housing v. Inclusive Communities Project is the fate of a crucial tool in challenging housing discrimination nationwide: so-called “disparate impact” claims that challenge housing practices that discriminate, without the difficult hurdle of proving that the discrimination was intentional.