Adair v. United States was a case in which the Supreme Court of the United States made an important decision on the issue of workers' rights. In this case, the Supreme Court ruled that employers could not discriminate against employees on the basis of their race, nationality, or other similar characteristics. This means that employers must treat all of their employees equally and fairly, regardless of their race or other characteristics. In other words, employers are not allowed to give some workers more (or less) favorable treatment than others because of the employee's race or other characteristics.