Historically, courts have ruled that plaintiffs making discrimination claims under the Fair Housing Act don’t have to prove intentional bias, according to an article in Bloomberg.

Now, the Supreme Court is weighing whether to hear an appeal from Texas officials who argue that intent to discriminate must be proven and that the “disparate impact” standard is too loose an interpretation of the landmark 1968 law that prohibited discrimination in housing.

However, the argument isn’t so easy.

“Intentional discrimination is often discreet,” says Joseph Rich, an attorney with the Lawyers’ Committee for Civil Rights Under Law. Requiring clear proof of intent to deny loans, sales, and services to minorities would often mean letting discrimination go unpunished, he says.