Last winter President Obama’s Department of Housing and Urban Development published a regulation pursuant to the Fair Housing Act that defines discrimination as actions or policies that while neutral and nondiscriminatory in their intent have a disparate impact, shown through statistics, on a group of persons defined in terms of race (and other protected groups).

The legality of the new rule was challenged almost a year ago by two of the largest among the trade associations representing homeowner’s insurers, the pith of their argument being that in passing the Fair Housing Act Congress defined discrimination as disparate treatment—the different treatment of individuals on account of race—and not as disparate impact. The agency thus lacked the authority to make the new rule. As the Supreme Court has said, in a passage we quoted in our editorial on the case, “An agency literally has no power to act . . . unless and until Congress confers power upon it.”